JP2005122220A - Optical element and optical fiber coupling structure, optical element and optical fiber coupling method, and optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coupling structure between an optical element and an optical fiber which has low cost and surely conducts transmission of light between the element and the fiber. <P>SOLUTION: A coupling structure 1000 which is used to couple an optical element and an optical fiber includes: an optical element 100 that includes an optical surface 180; an optical fiber 120; and a coupling section 140 that is joined with an end face 120a of the fiber 120 and the surface 180. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coupling structure between an optical element and an optical fiber, and a coupling method between the optical element and the optical fiber.

  The present invention also relates to an optical module and an optical transmission device including the coupling structure.

  In recent years, information communication has a tendency to increase in speed and capacity, and optical communication has been developed.

  In general, in optical communication, an electrical signal is converted into an optical signal, the optical signal is transmitted through an optical fiber, and the received optical signal is converted into an electrical signal. Conversion between an electrical signal and an optical signal is performed by an optical element (see, for example, Patent Document 1). When optical communication is performed by such a method, it is necessary to accurately align the positions of the optical element and the optical fiber and suppress the loss of light.

However, in general, since the optical surface (incident surface or output surface) of the optical element is fine and the diameter of the optical fiber is often fine, the alignment between the optical element and the optical fiber is required to be precise. The
JP 2001-59923 A

  An object of the present invention is to provide a coupling structure between an optical element and an optical fiber that is inexpensive and can reliably transmit light between the optical element and the optical fiber.

  It is another object of the present invention to provide a method for coupling an optical element and an optical fiber that is excellent in productivity and does not require precise alignment between the optical element and the optical fiber.

  Furthermore, the objective of this invention is providing the optical module and optical transmission apparatus containing the said coupling structure.

(1) The coupling structure between the optical element of the present invention and the optical fiber is as follows:
An optical element including an optical surface;
Optical fiber,
An end face of the optical fiber and a joint joined to the optical surface;
including.

  In this case, at least a part of the end face of the optical fiber can be opposed to the optical surface.

(2) The coupling structure between the optical element of the present invention and the optical fiber is as follows:
An optical element including an optical surface;
An optical fiber including a core and a cladding;
A coupling portion joined to an end surface of the core and the optical surface;
including.

  In this case, at least a part of the end surface of the core can be opposed to the optical surface.

  In the present application, the “optical surface” means a surface from which light is emitted or a surface into which light is introduced in an optical element. For example, when the optical element is a light emitting element, the optical surface is a surface from which light is emitted (emission surface). For example, when the optical element is a light receiving element, the optical surface is a surface (incident surface) into which light is introduced.

  Further, in the present application, “opposing” includes not only the case where two surfaces face each other in a parallel state but also the case where two surfaces face each other at a predetermined angle.

  Here, the end face of the optical fiber is not particularly limited as long as the coupling portion can be installed, and may be circular or elliptical. Similarly, the cut surface shape of the coupling portion is not particularly limited.

  According to the coupling structure of the optical element and the optical fiber of the present invention, it is possible to reliably transmit light between the optical element and the optical fiber by having the above-described configuration. In addition, a coupling structure between the optical element and the optical fiber can be obtained. Details will be described in the section of this embodiment.

  In the present invention, the material of the optical fiber is not particularly limited. For example, the present invention can be applied to an optical fiber made of quartz glass, plastic, a composite of plastic and quartz, or multicomponent glass. .

  (3) In the coupling structure of the optical element and the optical fiber, the refractive index of the coupling portion can be made substantially equal to the refractive index of the core of the optical fiber. According to this configuration, since light reflection at the interface between the coupling portion and the core can be reduced, light loss at the interface can be reduced.

  (4) In the coupling structure of the optical element and the optical fiber, the refractive index of the coupling portion can be made larger than the refractive index of the cladding of the optical fiber.

  (5) In the coupling structure of the optical element and the optical fiber, the end surface of the core and the end surface of the clad may be different in height at the end portion of the optical fiber joined to the coupling portion. it can.

  (I) In this case, the core may not be covered with the clad at the end. Thereby, in the said edge part, a convex part can be comprised with the said core and the said clad.

  Here, at the end portion, the periphery of the coupling portion can be covered with a sealing material. According to this structure, the said coupling | bond part can be reliably fixed on the end surface of the said core. As a result, the joint structure having a higher yield can be obtained.

  In this case, the refractive index of the sealing material can be made smaller than the refractive index of the core of the optical fiber and the refractive index of the coupling portion.

  In this case, the refractive index of the coupling portion can be made substantially equal to the refractive index of the core of the optical fiber, and the refractive index of the sealing material can be made substantially equal to the refractive index of the cladding of the optical fiber. According to this structure, the function similar to the core and clad | crud of an optical fiber can be provided to the said connection part and the said sealing material, respectively. Thereby, the loss of light can be reduced.

  (II) In this case, the clad may not cover the core at the end. Thereby, in the said edge part, a recessed part is comprised by the said core and the said clad. According to this structure, the said coupling | bond part can be reliably fixed on the end surface of the said core. As a result, the joint structure having a higher yield can be obtained.

  (6) In the coupling structure of the optical element and the optical fiber, the coupling part can be formed by curing a curable liquid material by applying energy.

  In this case, the coupling part may be made of an ultraviolet curable resin.

  (7) In the coupling structure of the optical element and the optical fiber, the optical element can be any one of a surface emitting semiconductor laser, a semiconductor light emitting diode, an EL device, and a photodiode.

(8) The optical module of the present invention includes the above-described coupling structure of the optical element of the present invention and an optical fiber,
A semiconductor chip electrically connected to the optical element.

  According to the optical module of the present invention, there is provided a coupling structure between the optical element and the optical fiber that includes the coupling structure and can reliably transmit light between the optical element and the optical fiber. Can be installed. Further, in comparison with a general optical module in which a lens is separately provided between the optical fiber and the optical element, in the optical module of the present invention, the positions of the optical fiber and the optical element through the coupling portion. Since only the alignment is sufficient, the alignment can be simplified. Furthermore, by including a coupling structure that directly couples the optical element and the optical fiber via the coupling portion, highly accurate alignment is not necessary. Therefore, simplification, downsizing, and cost reduction of the device can be achieved.

(9) The light transmission device of the present invention comprises:
Optical fiber,
A light-emitting element including an incident surface, and causing light emitted from the incident surface to be incident on one end surface of the optical fiber;
A semiconductor chip electrically connected to the light emitting element;
A light receiving element that includes an emission surface and introduces light emitted from the other end surface of the optical fiber from the emission surface;
A semiconductor chip electrically connected to the light receiving element,
At least one of the coupling structure between the light emitting element and the optical fiber and the coupling structure between the light receiving element and the optical fiber is composed of the above-described coupling structure between the optical element of the present invention and the optical fiber.

(10) The method of coupling the optical element of the present invention with an optical fiber is as follows:
(A) discharging a droplet to at least one of the end face of the optical fiber and the optical surface of the optical element to form a coupling portion precursor;
(B) curing the binder precursor in a state where the end face of the optical fiber and the optical surface are bonded via the coupler precursor to form a coupler.

  In this case, in (b), the end surface of the optical fiber and the optical surface are joined via the coupling portion precursor with at least a part of the end surface of the optical fiber facing the optical surface. Can be included.

  According to the method for coupling an optical element and an optical fiber of the present invention, the productivity is excellent and it is not necessary to precisely align the optical element and the optical fiber. Further, the optical element and the optical fiber can be joined by a simple method via the coupling portion. Details will be described in the section of this embodiment.

(11) Further, the method of coupling the optical element of the present invention with an optical fiber is as follows:
(A) discharging a droplet to at least one of the end surface of the core of the optical fiber and the optical surface of the optical element to form a coupling portion precursor;
(B) In a state where the end face of the core and the optical surface are bonded via the bonding portion precursor, the bonding body precursor is cured to form a bonding portion.

  In this case, in (b), the end surface of the core and the optical surface are bonded via the coupling portion precursor in a state where at least a part of the end surface of the core is opposed to the optical surface. , Can be included.

  In this case, in the method for coupling the optical element and the optical fiber, the height of the end face of the core may be different from the height of the end face of the clad.

  According to the coupling method of the optical element and the optical fiber of the present invention, the productivity is excellent, and it is not necessary to precisely align the end surface and the optical surface. Further, the optical element and the optical fiber can be joined by a simple method via the coupling portion. Details will be described in the section of this embodiment.

  (12) In this method of coupling an optical element and an optical fiber, the droplets can be ejected by an ink jet method. The ink jet method is a method of discharging droplets using an ink jet head. According to this method, since the discharge amount of the droplet can be finely adjusted, a fine coupling portion precursor can be simply placed on at least one of the end face of the optical fiber and the optical surface. Can do.

  (13) In this method of coupling an optical element and an optical fiber, the coupling portion precursor can be cured by adding energy.

  (14) In this method of coupling an optical element and an optical fiber, the optical element can be any one of a surface emitting semiconductor laser, a semiconductor light emitting diode, an EL device, and a photodiode.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1. FIG. 1 is a side view schematically showing a coupling structure between an optical element and an optical fiber according to a first embodiment to which the present invention is applied. FIG. 1 shows a coupling unit 1000 as a coupling structure between an optical element and an optical fiber.

  As shown in FIG. 1, the coupling unit 1000 includes an optical element 100, an optical fiber 120, and a coupling unit 140. Hereinafter, each component of the coupling unit 1000 will be described.

[Optical element]
The optical element 100 may be a light emitting element or a light receiving element. The optical element 100 can be, for example, a light emitting element that emits light in a direction perpendicular to the substrate, or a light receiving element that introduces light from a direction perpendicular to the substrate. When the optical element 100 is a light emitting element, the light emitted from the optical surface 180 can be efficiently introduced into the optical fiber 120 via the coupling portion 140. Alternatively, when the optical element 100 is a light receiving element, the light emitted from the optical fiber 120 can be efficiently introduced from the optical surface 180 via the coupling portion 140. The optical element 100 is not particularly limited. For example, the optical element 100 can be any one of a surface emitting semiconductor laser, a semiconductor light emitting diode, an EL device, and a photodiode.

  The optical element 100 includes an optical surface 180. In the present embodiment, a case where the optical surface 180 is provided on the upper surface of the columnar portion 130 is shown. For example, when the optical element 100 is a surface emitting semiconductor laser, the columnar portion 130 constitutes a part of a resonator. When the optical element 100 is a light emitting diode, the columnar portion 130 includes an active layer.

  As shown in FIG. 1, the optical element 100 is joined to the optical fiber 120 via a coupling portion 140. That is, the relative position of the optical element 100 and the optical fiber 120 is fixed by the coupling portion 140. In this coupling unit 1000, the optical surface 180 of the optical element 100 faces at least a part of the end surface 120 a of the optical fiber 120.

[Optical fiber]
The optical fiber 120 generally includes a core 122 and a cladding 124. The clad 124 surrounds the core 122 concentrically. In the optical fiber 120, light is reflected at the boundary between the core 122 and the cladding 124, the light is confined in the core 122, and the light propagates in the core 122. The periphery of the clad 124 can be protected by a jacket (not shown).

  In the present embodiment, the case where the cross-sectional shape of the optical fiber 120 is circular has been described, but the cross-sectional shape of the optical fiber 120 is not particularly limited. The same applies to optical fibers shown in the embodiments and modifications described later. For example, as the optical fiber 120, an optical fiber having an elliptical cross-sectional shape, or an optical fiber having a circular or elliptical core and a cladding having other shapes can be used.

  In FIG. 1, an end portion (one end portion) of the optical fiber 120 is shown. Note that the optical element 100 may be installed via the coupling portion 140 at both ends of the optical fiber 120. In this case, one of the optical elements 100 installed at both ends is a light emitting element, and the other is a light receiving element. Alternatively, the optical element 100 may be installed on the end face of the optical fiber 120 via the coupling portion 140 only at either one of both ends of the optical fiber 120. The same applies to the coupling structure of the optical element and the optical fiber shown in the embodiments and modifications described later.

[Joint part]
As illustrated in FIG. 1, the coupling unit 140 is bonded to the end surface 120 a of the optical fiber 120 and the optical surface 180 of the optical element 100.

  When light emitted from the optical fiber 120 is incident on, for example, a light receiving element (not shown), the light emitted from the end face 120a of the optical fiber 120 can enter the light receiving element after passing through the coupling portion 140. Alternatively, when light emitted from a light emitting element (not shown) is incident on the end face 120a of the optical fiber 120, for example, the light emitted from the light emitting element is incident on the end face 120a of the optical fiber 120 after passing through the coupling portion 140. can do.

  The coupling part 140 may be formed by curing a curable liquid material by applying energy. Examples of the liquid material include an ultraviolet curable resin and a thermosetting resin precursor. Examples of the ultraviolet curable resin include an ultraviolet curable acrylic resin and an epoxy resin. An example of the thermosetting resin is a thermosetting polyimide resin.

  The precursor of the ultraviolet curable resin is cured by short-time ultraviolet irradiation. For this reason, it can harden | cure, without passing through the process which is easy to give a damage with respect to elements, such as a thermal process. For this reason, when forming the coupling | bond part 140 using the precursor of an ultraviolet curable resin, the influence on an element can be decreased.

  Specifically, the coupling unit 140 ejects droplets to at least one of the end surface 120a of the optical fiber 120 and the optical surface 180 of the optical element 100 to form a coupling unit precursor (described later). Thereafter, this bonding portion precursor can be cured.

  More specifically, the coupling portion 140 is made of a precursor of an ultraviolet curable resin or a thermosetting resin. In this case, the shape and size of the coupling portion 140 can be controlled by adjusting the type and amount of the liquid material used when forming the coupling portion 140. The shape and size of the coupling portion 140 are determined based on the distance between the end surface 120 a of the optical fiber 120 and the optical surface 180. In other words, the shape and size of the coupling portion 140 are determined so that the end surface 120a of the optical fiber 120 and the optical surface 180 can be bonded according to the distance between the end surface 120a of the optical fiber 120 and the optical surface 180. This also applies to embodiments and modifications described later.

  Further, the refractive index of the coupling portion 140 can be made larger than the refractive index of the cladding 120 of the optical fiber 120. According to this configuration, introduction of light into the clad 124 can be reduced.

  Furthermore, the refractive index of the coupling portion 140 can be made substantially equal to the refractive index of the core 122 of the optical fiber 120. According to this configuration, since light reflection at the interface between the coupling portion 140 and the core 122 can be reduced, the loss of light at the interface can be reduced. The same applies to the embodiments and modifications described later.

2. Next, a method for manufacturing the coupling unit 1000 shown in FIG. 1 will be described with reference to FIGS. 2 and 3. 2 to 4 are diagrams schematically showing one step of the method of coupling the optical element 100 and the optical fiber 150. FIG.

[Formation of joint precursor]
First, the coupling | bond part precursor 140a is formed on the end surface 120a of the optical fiber 120, and the optical surface 180 (refer FIG. 2 and FIG. 3). Specifically, a droplet 140b of a liquid material for forming the coupling portion 140 is ejected to at least one of the end surface 120a of the optical fiber 120 and the optical surface 180 of the optical element 100, and the coupling portion precursor. Form body 140a. As described above, the liquid material has a property of being curable by applying energy.

  In the present embodiment, as shown in FIG. 2, droplets 140b are ejected onto both the end surface 120a and the optical surface 180 of the optical fiber 120, and the coupling portion precursors 140x and 140y (see FIG. 3) are discharged. The case of forming will be described. As shown in a second embodiment to be described later, after a droplet 140b is ejected onto one of the end surface 120a and the optical surface 180 of the optical fiber 120 to form a coupling portion precursor, the end surface 120a The coupling portion precursor 140a (described later: see FIG. 4) may be formed so as to face the optical surface 180.

  As a method for discharging the droplet 140b, for example, a dispenser method or an ink jet method can be used. The dispenser method is a general method for ejecting the droplets 140b, and is effective when ejecting the droplets 140b over a relatively wide area.

  The inkjet method is a method of ejecting droplets using an inkjet head, and the position at which the droplets are ejected can be controlled in units of μm. In addition, the amount of droplets to be ejected can be controlled in units of picoliters. For this reason, the coupling | bond part of a fine structure can be produced on the end surface of a fine optical fiber.

  Here, as shown in FIG. 2, a method for ejecting droplets 140 b using the inkjet head 110 will be described. As shown in FIG. 2, a liquid material droplet 140 b is ejected onto the end surface 120 a and the optical surface 180 of the optical fiber 120 using the inkjet head 110. Thereby, as shown in FIG. 3, the coupling portion precursor 140 x is formed on the end surface 120 a, and the coupling portion precursor 140 y is formed on the optical surface 180.

  Examples of the inkjet ejection method include: (i) a method in which pressure is generated by changing the size of bubbles in a liquid (here, a bonding portion precursor) by heat, and the liquid is ejected; (ii) by a piezoelectric element There is a method of discharging liquid by the generated pressure. From the viewpoint of controllability of pressure, the method (ii) is desirable.

  The alignment between the position of the nozzle of the inkjet head and the discharge position of the droplet is performed using a known image recognition technique used in an exposure process or an inspection process in a general semiconductor integrated circuit manufacturing process. For example, alignment between the position of the nozzle 112 of the inkjet head 120 and the position of the optical surface 180 of the optical element 100 and the end surface 120a of the optical fiber 120 is performed. After alignment, the voltage applied to the inkjet head 110 is controlled, and then the droplet 140b is ejected. Thereby, as shown in FIG. 3, coupling portion precursors 140 x and 140 y are formed on the optical surface 180 and the end surface 120 a of the optical fiber 120, respectively.

  In the present embodiment, since the optical element 100 includes the columnar portion 130 and the optical surface 180 is provided on the upper surface of the columnar portion 130, the coupling portion precursor 140 x is formed on the upper surface of the columnar portion 130. . When the droplet 140b is ejected onto the optical surface 180, the droplet 140b is deposited on the upper surface of the columnar portion 130 by surface tension. Thereby, the coupling | bond part precursor 140x of a desired shape and magnitude | size is obtained.

  The coupling portion precursor 140y is formed on the end surface 120a of the optical fiber 120. In this case as well, when the droplet 140b is ejected onto the end surface 120a, the droplet 140b is deposited on the end surface 120a by surface tension. Thereby, the coupling | bond part precursor 140y of a desired shape and a magnitude | size is obtained.

  Here, if necessary, the droplets 140b are ejected a plurality of times to form the coupling portion precursors 140x and 140y in a desired shape and size. The coupling portion precursors 140x and 140y are formed in such a shape and size that at least a part thereof can be bonded to each other when the distance between the end surface 120a of the optical fiber 120 and the optical surface 180 is set to a predetermined value.

  In addition, before discharging the droplet 140b, a lyophilic process or a liquid repellent process is performed on the end surface 120a and the optical surface 180 of the optical fiber 120 as necessary. Thereby, the wettability of the end surface 120a and the optical surface 180 with respect to the droplet 140b can be controlled. Thereby, the shape and size of the coupling portion 140 can be controlled more strictly.

Next, the end surface 120a of the optical fiber 120 and the optical surface 180 are opposed to each other. In the present embodiment, at least a part of the end surface 120a is opposed to the optical surface 180. In this case, from the viewpoint of light utilization efficiency, as shown in FIG. 4, the optical surface 180 is centered on a straight line R ₁ that passes through the center of the end surface 120 a and is perpendicular to the end surface 120 a. It is desirable to install fiber 120 and optical surface 180.

  In addition, here, the coupling portion precursor 140x and the coupling portion precursor 140y (see FIG. 3) are brought into contact with each other so that the end surface 120a of the optical fiber 120 and the optical surface 180 are close to each other at a predetermined distance. . Thereby, the coupling | bond part precursor 140x which is a liquid state, and the coupling | bond part precursor 140y are integrated, and the coupling | bond part precursor 140a is formed (refer FIG. 4). The joint portion precursor 140a obtained here is bonded to the end face 120a and the optical surface 180, as shown in FIG.

[Formation of joints]
Next, as shown in FIG. 4, the bonding portion precursor 140 a is cured to form the bonding portion 140. Specifically, energy 113 such as heat or light is applied to the bonding portion precursor 140a.

  When curing the bonding portion precursor 140a, an appropriate method is selected depending on the type of the liquid material. Specific examples of the curing means include addition of thermal energy or irradiation with light such as ultraviolet rays or laser light. Further, the amount of energy 113 to be added is appropriately adjusted depending on the shape, size, and material of the bonding portion precursor 140a. Through the above steps, a coupling unit 1000 including the optical element 100, the optical fiber 120, and the coupling portion 140 is obtained (see FIG. 1).

3. Effects According to the coupling structure between the optical element and the optical fiber according to the present embodiment, the coupling is inexpensive and can reliably transmit light between the optical element 100 and the optical fiber 120. A structure (coupling unit 1000) can be obtained.

  Further, according to the method for coupling the optical element and the optical fiber according to the present embodiment, the productivity is excellent, and it is not necessary to precisely align the optical element 100 and the optical fiber 120. The above effect will be described in detail below.

  (1) First, loss of light propagating between the optical fiber 120 and the optical element 100 can be reduced by joining the end surface 120a of the optical fiber 120 and the optical surface 180 via the coupling portion 140. Can be reduced. In order to explain the reason, first, a general coupling structure between an optical element and an optical fiber will be described below.

  In a general coupling structure between an optical element and an optical fiber, no coupling portion is formed between the optical element and the optical fiber. For this reason, in order to efficiently introduce the light emitted from the optical element into the optical fiber or to efficiently introduce the light emitted from the optical fiber into the optical element, alignment between the optical element and the optical fiber is required. It must be done strictly. Further, when the optical element is a light emitting element, the light emitted from the optical surface may be incident on the optical surface after being reflected by the end surface of the optical fiber. There has been a problem that the characteristics of the optical element are changed by the incident light (return light).

  On the other hand, according to the coupling structure (coupling unit 1000) of the present embodiment, since the coupling portion 140 is joined between the end surface 120a of the optical fiber 120 and the optical surface 180, the optical element 100 and the light Even if the alignment with the fiber 120 is not strictly performed, the light emitted from the optical element 100 (or the optical fiber 120) can be efficiently introduced into the optical fiber 120 (or the optical element 100). That is, according to the coupling unit 1000, it is possible to reliably transmit light between the optical element 100 and the optical fiber 120 without strict alignment. Further, since the end surface 120a of the optical fiber 120 and the optical surface 180 are joined via the coupling portion 140, it is possible to prevent the above-described return light from being generated. Thereby, the characteristics of the optical element 100 can be maintained.

For example, as in the modified example (binding unit 1100) shown in FIG. 17 (a), on a straight line perpendicular _{R 1} in the center through and the end face 120a of the end face 120a of the optical fiber 120, the center of the optical surface 180 is positioned Even if not, light can be efficiently propagated by joining the end surface 120a and the optical surface 180 via the coupling portion 940.

Further, for example, as in the modified example (binding unit 3100) shown in FIG. 17 (b), the center of the end face 222a on the street and the end surface 222a and a line perpendicular _{R 2} of the core 222, the center of the optical surface 180 is positioned Even if not, light can be efficiently propagated by joining the end surface 222a and the optical surface 180 via the coupling portion 740.

  In FIGS. 17A and 17B, the coupling portions 740 and 940 are made of the same material as the coupling portion 140 shown in the present embodiment and are formed by the same method. It is.

  (2) Secondly, the coupling portion 140 is formed by curing a liquid material that can be cured by applying energy. That is, a coupling portion precursor is formed on one of the end surface 120a and the optical surface 180 of the optical fiber 120, and the coupling portion precursor is cured in contact with the end surface 120a and the optical surface 180. Thereby, since the optical element 100 and the optical fiber 120 are joined via the coupling part 140, it is not necessary to precisely align the optical element 100 and the optical fiber 120.

  Further, the shape and size of the coupling portion precursor 140a can be controlled by the discharge amount of the droplet 140b. Accordingly, the shape and size of the coupling portion precursor 140a can be adjusted according to the distance between the optical element 100 and the optical fiber 120.

(Second Embodiment)
1. FIG. 5 is a side view schematically showing a coupling structure between an optical element and an optical fiber according to a second embodiment to which the present invention is applied. FIG. 5 shows a coupling unit 2000 as a coupling structure between the optical element and the optical fiber.

  As illustrated in FIG. 5, the coupling unit 2000 includes an optical element 100, an optical fiber 120, and a coupling unit 840.

  In this coupling unit 2000, the method of forming the coupling portion 840 is different from the coupling portion 140 (see FIG. 1) shown in the first embodiment. The constituent elements other than those described above are the same as the constituent elements of the coupling unit 1000 of the first embodiment. In this connection unit 2000, the points having the same configuration as the connection unit 1000 of the first embodiment are denoted by the same reference numerals in principle, and detailed description thereof is omitted.

2. Next, a method for manufacturing the coupling unit 2000 shown in FIG. 5 will be described with reference to FIGS. Note that, in principle, the description of the same steps as the method for coupling the optical element 100 and the optical fiber 120 of the first embodiment described above is omitted.

[Formation of joint precursor]
In the present embodiment, as shown in FIG. 6, a case where the coupling portion precursor 840 a is formed only on the end face 120 a of the optical fiber 120 is shown. The method of forming the joint portion precursor 840a is the same as that of the joint portion precursors 140x and 140y shown in the first embodiment. That is, a droplet 140b (see FIG. 2) is ejected onto the end face 120a of the optical fiber 120, thereby forming a coupling portion precursor 840a on the end face 120a (see FIG. 6).

[Formation of joints]
The method for forming the coupling portion 840 (see FIG. 5) is the same as the method described in the first embodiment. Further, the coupling portion 840 can be made of the same material as the coupling portion 140 shown in the first embodiment.

  Specifically, as shown in FIG. 7, in a state where the end surface 120a of the optical fiber 120 and the optical surface 180 are opposed to each other, a predetermined distance is provided between the end surface 120a of the optical fiber 120 and the optical surface 180. And the coupling portion precursor 840a is brought into contact with the optical surface 180. In this state, energy 113 is applied to the bond portion precursor 840a to cure the bond portion precursor 840a. Thereby, as shown in FIG. 5, a coupling portion 840 is formed.

[Others]
In the present embodiment, the case where the coupling portion 840 is formed through the process of forming the coupling portion precursor 840a only on the end surface 120a of the optical fiber 120 has been described. Alternatively, although not illustrated, the coupling portion 840a is coupled only to the optical surface 180. After forming the part precursor, the coupling part may be formed. In this case, when the coupling portion precursor is brought into contact with the end surface 120a, the coupling portion precursor is brought into contact with at least the end surface of the core in the end surface 120a.

3. Operational Effects According to the coupling structure and coupling method between the optical element and the optical fiber of the present embodiment, the same operational effects as the coupling structure and coupling method of the first embodiment are obtained.

  Furthermore, according to the coupling structure and coupling method between the optical element and the optical fiber of the present embodiment, through the step of forming the coupling portion precursor on at least one of the end surface 120a and the optical surface 180 of the optical fiber 120, A joint is formed. Thereby, the binding structure can be obtained by a simpler method.

  In particular, when the coupling portion precursor 840a is formed on the end surface 120a of the optical fiber 120, surface tension mainly acts on the coupling portion precursor 840a unless the side surface of the optical fiber 120 is wetted by the coupling portion precursor 840a. . For this reason, the shape and size of the bonding portion precursor 840a can be controlled by adjusting the amount of droplets for forming the bonding portion precursor 840a. Thereby, the coupling part 840 having a desired shape and size can be obtained.

(Third embodiment)
1. FIG. 8 is a side view schematically showing a coupling structure between an optical element and an optical fiber according to a third embodiment to which the present invention is applied. FIG. 8 shows a coupling unit 3000 as a coupling structure between an optical element and an optical fiber.

  As illustrated in FIG. 8, the coupling unit 3000 according to the present embodiment includes an optical element 100, an optical fiber 220, and a coupling unit 240.

  As shown in FIG. 8, the coupling unit 3000 has an end portion of the optical fiber 220 in which the end surface 222a of the core 222 and the end surface 224a of the clad 224 have different heights, and the end surface 222a and the optical surface 180 are different from each other. It has a configuration different from the coupling units of the first and second embodiments in that they are joined via the coupling portion 240.

  Next, each component of the coupling unit 3000 will be described. In this connection unit 3000, as to the points having the same configuration as that of the connection unit 1000 of the first embodiment, in principle, the same reference numerals are attached and detailed description is omitted.

[Optical fiber]
The optical fiber 220 includes a core 222 and a cladding 224. In the present embodiment, the case where the core 222 is not covered with the clad 224 at the end of the optical fiber 220 shown in FIG. That is, at the end of the optical fiber 220 shown in FIG. 8, the end face 222 a of the core 222 protrudes from the end face 224 a of the clad 224, and the core 222 and the clad 224 constitute a convex portion 260.

  Further, the optical fiber 220 can be formed of the same material as that shown as the material of the optical fiber 120 in the first embodiment.

[Joint part]
As shown in FIG. 8, the coupling portion 240 is provided on the end surface 222 a of the core 222 of the optical fiber 220. The coupling part 240 can be made of the same material as the coupling part 140 shown in the first embodiment.

  The coupling portion 240 is formed by the same method as the coupling portion 840 (see FIG. 5) of the second embodiment. Specifically, the joint 240 discharges droplets to the end face 222a of the core 222 of the optical fiber 220 to form a joint precursor (described later), and then cures the joint precursor. Can be formed.

2. Next, a method for coupling the optical element and the optical fiber shown in FIG. 8 will be described with reference to FIGS. Note that, in principle, the description of the same steps as those in the method for coupling the optical element and the optical fiber of the first embodiment described above is omitted.

[Processing of core and clad end faces]
First, a process of projecting the end surface 222a of the core 222 from the end surface 224a of the clad 224 will be described. In order to make the end surface 222a of the core 222 protrude from the end surface 224a of the clad 224, the following methods (1) and (2) can be specifically exemplified.

(1) Method by Wet Etching First, the step of causing the end face 222a of the core 222 to protrude from the end face 224a of the clad 224 by wet etching will be described with reference to FIG. Here, a case where the optical fiber 220 is made of a silica-based optical fiber will be described.

  In general, in an optical fiber, the core and the clad are formed of different components in order to make the refractive index of the core larger than that of the clad. Using the difference in the components of the core and the clad, the core or the clad can be selectively removed by wet etching.

  Here, an etchant capable of selectively removing the clad 224 by performing wet etching on the optical fiber 220 (see FIG. 9) having a flat end surface is used. As a result, the end face 222 a of the core 222 and the end face 224 a of the clad 224 can be protruded.

  As an etchant used for selective etching between the core and the clad of the silica-based optical fiber, for example, an aqueous solution (buffer hydrofluoric acid aqueous solution) in which hydrofluoric acid and ammonium fluoride are mixed can be used. The clad 224 can be selectively removed by adjusting the concentration of hydrofluoric acid and ammonium fluoride in the buffer hydrofluoric acid aqueous solution.

  A schematic diagram of wet etching is shown in FIG. As shown in FIG. 9, the end of the optical fiber 220 is immersed in the etchant 230. Thereby, since the clad 224 is selectively dissolved, the clad 224 can be selectively removed at the end of the optical fiber 220.

Specifically, by using a buffer hydrofluoric acid aqueous solution prepared by using 40 wt% ammonium fluoride aqueous solution, 50 wt% hydrofluoric acid aqueous solution and pure water (H ₂ O) in a predetermined volume ratio. The clad 224 can be selectively removed.

  Note that the core 222 can be selectively removed by adjusting the concentrations of hydrofluoric acid and ammonium fluoride in the buffer hydrofluoric acid aqueous solution. This case will be described in detail in an embodiment described later.

(2) Method by Photo Curing Next, the process of extending the core 222 by photo curing will be described with reference to FIG. In this method, the end surface 222 a of the core 222 is protruded from the end surface 224 a of the clad 224 by extending a photocurable resin on the end surface of the core 222 of the optical fiber 220. Here, the material of the optical fiber 220 is not particularly limited as long as the adhesiveness with the photocurable resin can be secured.

  Specifically, as shown in FIG. 10, the end portion (one end portion) of the optical fiber 220 including the end face 222a is immersed in a liquid material 232 containing a precursor of an ultraviolet curable resin. At the other end of the optical fiber 220, ultraviolet rays 213 are incident from the end face 222 b of the core 222. Thereby, the ultraviolet ray 213 incident from the end face 222 b propagates through the core 222 and then exits from the end face 222 a of the core 222. Here, since ultraviolet light is not introduced into the clad 224, no ultraviolet light is emitted from the clad 224, and the ultraviolet light 213 is emitted only from the end face 222 a of the core 222. That is, the ultraviolet curable resin precursor contained in the liquid material 230 reacts at the end surface 222 a of the core 222 by the ultraviolet rays 213 emitted from the end surface 222 a of the core 222. Thereby, the core 222 is extended by forming the ultraviolet curable resin on the end face 222 a of the core 222. As a result, as shown in FIG. 8, an optical fiber 220 having a structure in which the end surface 222a of the core 222 protrudes from the end surface 224a of the cladding 224 is obtained.

  Note that FIG. 10 shows an example in which the core 222 is extended with the end of the optical fiber 220 immersed in the liquid material 232. Here, instead of immersing the end portion of the optical fiber 220 in the liquid material 232, the liquid material 232 is installed on the end surface 222 of the optical fiber 220, as shown in FIG. The core 222 may be extended by introducing ultraviolet rays from the end face of the core 222 at one end.

[Formation of joints]
Next, the coupling portion 240 is formed on the end surface 222 a of the core 222 of the optical fiber 220. The present embodiment is the same as the method of forming the coupling portion 140 in the first embodiment, except that the coupling portion 240 is formed on the end surface 222a of the core 222. Further, as the material of the coupling portion 240, the same material as that of the coupling portion 140 shown in the first embodiment can be used.

  Specifically, a droplet made of a liquid material for forming the coupling portion 240 is discharged onto the end surface 222 a of the core 222 of the optical fiber 220. As a result, as shown in FIG. 11, the coupling portion precursor 240 a is formed on the end surface 222 a of the core 222. Next, in a state where the end surface 222a of the core 222 and the optical surface 180 are opposed to each other, the end surface 222a of the core 222 and the optical surface 180 are brought close to each other at a predetermined distance, so that the coupling portion precursor 240a and the optical surface 180 is brought into contact. In this state, energy is applied to the bonding portion precursor 240a to cure the bonding portion precursor 240a. Thereby, the coupling | bond part 240 is obtained (refer FIG. 8).

  As a method of curing the bonding portion precursor 240a, the same method as the method of curing the bonding portion precursor 140a described in the first embodiment can be used. Thereby, the coupling structure (coupling unit 3000) of the optical element 100 and the optical fiber 220 is obtained (see FIG. 8).

3. Operational Effects According to the coupling structure and coupling method between the optical element and the optical fiber of the present embodiment, the same operational effects as the coupling structure and coupling method of the first embodiment are obtained.

  Furthermore, according to the coupling structure and coupling method between the optical element and the optical fiber of the present embodiment, the coupling part 240 is provided on the end surface 222 a of the core 222 of the optical fiber 220. In the optical fiber 220, light actually propagates at the core 222. That is, since the coupling portion 240 is provided only on the end surface 222a of the core 222, when the optical element 100 is a light receiving element, light is more efficiently transmitted from the core 222 to the optical element 100 via the coupling portion 240. Can be introduced well. Alternatively, when the optical element 100 is a light emitting element, light can be more efficiently introduced from the optical element 100 to the core 222 via the coupling unit 240.

4). Next, another modification of the coupling structure between the optical element and the optical fiber according to the present embodiment will be described.

(1) Modification 1
FIG. 12 is a diagram schematically showing a coupling structure between an optical element and an optical fiber, which is a modification of the present embodiment. FIG. 13 is a diagram schematically showing a method of coupling an optical element and an optical fiber, which is a modification shown in FIG. FIG. 12 shows a coupling unit 3200 as a coupling structure between an optical element and an optical fiber.

  In this coupling unit 3200, the shape and size of the coupling part 340 are different from the coupling part 240 (see FIG. 8) shown in the present embodiment. Regarding the components other than this point, the coupling unit 3200 includes the same components as the coupling unit 3000 shown in FIG.

  FIG. 13 shows a state in which the coupling portion precursor 340 a is installed on the end face 222 a of the core 222. By adjusting the shape and size of the bonding portion precursor 340a, the shape and size of the bonding portion 340 can be adjusted.

For example, referring to FIG. 13, in this optical fiber 222, a convex portion is constituted by the end surface 222 a of the core 222 and the end surface 224 a of the cladding 224. Here, when forming the coupling part precursor 340a on the end face 222a of the core 222, by adjusting the amount of droplets to be used, the maximum diameter _{d 2} of the coupling part precursor 340a, the end face 222a diameter d It can be greater than ₁ . Thereby, the coupling part 340 can be formed larger. As a result, it is possible to widen the margin of the distance when joining the end surface 220a of the core 222 and the optical surface 180 of the optical element 100.

(2) Modification 2
FIG. 14 is a diagram schematically showing a coupling structure between an optical element and an optical fiber, which is a modification of the present embodiment. FIG. 14 shows a coupling unit 3300 as a coupling structure between an optical element and an optical fiber.

  A coupling unit 3300 shown in FIG. 14 is obtained by embedding the protruding portion of the core 222, the periphery of the coupling part 240 and the columnar part 130 with a sealing material 226 at the end of the coupling unit 3000 shown in FIG.

  That is, in this coupling unit 3300, the configuration other than the sealing material 226 is the same as that of the coupling unit 3000 (see FIG. 8) of the present embodiment. Therefore, the coupling unit 3300 has the same function and effect as the coupling unit 3000.

  Furthermore, in the coupling unit 3000, the coupling portion 240 can be reliably fixed between the end surface 222 a of the core 222 and the optical surface 180 by covering the periphery of the coupling portion 240 with the sealing material 226. As a result, the yield can be increased.

  In addition, the refractive index of the sealing material 226 is preferably smaller than the refractive index of the core 222 and the refractive index of the coupling portion 240. Accordingly, the sealing material 226 can be provided with a function as a clad for confining light propagating in the core 222 and the coupling portion 240 at the end of the optical fiber 220 shown in FIG.

  Further, the refractive index of the coupling portion 240 is preferably the same as the refractive index of the core 222, and the refractive index of the sealing material 226 is more preferably the same as the refractive index of the cladding 224. That is, in this case, the same function as the core and the clad of the optical fiber can be imparted to the coupling portion 240 and the sealing material 226, respectively. Thereby, the loss of light can be reduced.

  The above refractive index is the same in other embodiments and modifications.

  The material of the sealing material 226 is not particularly limited. For example, a resin material such as an ultraviolet curable resin or a thermosetting resin can be used.

(Fourth embodiment)
1. FIG. 15 is a side view schematically showing a coupling structure between an optical element and an optical fiber according to a fourth embodiment to which the present invention is applied. FIG. 15 shows a coupling unit 4000 as a coupling structure between an optical element and an optical fiber.

  As illustrated in FIG. 15, the coupling unit 4000 according to the present embodiment includes an optical element 100, an optical fiber 320, and a coupling unit 340.

  As shown in FIG. 15, the coupling unit 4000 has an end portion 322a of the core 322 and an end surface 324a of the clad 324 that are different in height at the end portion of the optical fiber 320, and an end surface 322a of the core 322 of the optical fiber 320. It has the same configuration as the coupling unit 3000 of the third embodiment in that the coupling unit 340 is provided on the top.

  On the other hand, the coupling unit 4000 of this embodiment is different from the coupling unit 3000 of the third embodiment in that the clad 324 does not cover the core 322 at the end of the optical fiber 320 as shown in FIG. Have different configurations.

  Next, each component of the coupling unit 4000 will be described. In this connection unit 4000, as to the points having the same configuration as that of the connection unit 3000 (see FIG. 8) of the third embodiment, the same reference numerals are given in principle, and detailed description thereof is omitted.

[Optical fiber]
The optical fiber 320 includes a core 322 and a cladding 324. In the present embodiment, as described above, the case where the cladding 324 does not cover the core 322 at the end of the optical fiber 320 is shown. That is, as shown in FIG. 15, at the end of the optical fiber 320, the end surface 324 a of the clad 324 protrudes from the end surface 322 a of the core 322, and the core 322 and the clad 324 constitute a recess 360.

  The optical fiber 320 can be formed of the same material as that shown as the material of the optical fiber 120 in the first embodiment.

[Joint part]
As shown in FIG. 15, the coupling portion 340 is provided on the end surface 322 a of the core 322 of the optical fiber 320. The coupling portion 340 can be made of the same material as the coupling portion 240 (see FIG. 8) shown in the third embodiment.

  Further, the coupling portion 340 is formed by the same method as the coupling portion 240 shown in the third embodiment. Specifically, the coupling unit 340 discharges droplets to the end surface 322a of the core 322 of the optical fiber 320 to form a coupling unit precursor (described later), and then cures the coupling unit precursor. Can be formed.

2. Coupling Method between Optical Element and Optical Fiber A coupling method between the optical element and the optical fiber shown in FIG. 15 will be described with reference to FIG. Note that, in principle, the description of the same steps as those in the method of coupling the optical element and the optical fiber of the third embodiment described above is omitted.

[Processing of core and clad end faces]
In the present embodiment, the end surfaces of the core 322 and the clad 324 of the optical fiber 320 can be processed by the method using wet etching among the methods described in the third embodiment. Specifically, in wet etching, etching is performed under conditions that allow the core 322 to be selectively removed by adjusting the type and concentration of each component constituting the etchant.

  For example, when the optical fiber 320 is made of a quartz optical fiber and a buffer hydrofluoric acid aqueous solution is used as an etchant, the core 322 is selected by adjusting the concentrations of hydrofluoric acid and ammonium fluoride in the buffer hydrofluoric acid aqueous solution. Can be removed.

  Specifically, the aqueous solution used when removing the clad in the column of the second embodiment can be used by changing the ratio of each component.

[Formation of joints]
Next, a coupling portion precursor 340 a is formed on the end surface 322 a of the core 322 of the optical fiber 320. In the present embodiment, the method for forming the coupling portion 340 is the same as the method for forming the coupling portion 240 in the third embodiment. Moreover, the material of the coupling | bond part precursor 340a can use the material similar to the coupling | bond part precursor 140a (refer FIG. 4) shown in 1st Embodiment.

  Specifically, a droplet made of a liquid material for forming the coupling portion 340 is ejected onto the end surface 322a of the core 322 of the optical fiber 320, so that the coupling portion precursor 340a is formed as shown in FIG. It is formed on the end surface 322 a of the core 322. Next, in a state where the end surface 322a of the core 322 and the optical surface 180 (see FIG. 15) of the optical element 100 face each other, the end surface 322a of the core 322 and the optical surface 180 are brought close to each other at a predetermined distance. The bonding portion precursor 340a and the optical surface 180 are brought into contact with each other. In this state, energy is applied to the bond portion precursor 340a to cure the bond portion precursor 340a. Thereby, the coupling portion 340 is formed. Thus, a coupling structure (coupling unit 4000) between the optical element 100 and the optical fiber 320 is obtained (see FIG. 15).

3. Operational Effects According to the coupling structure and coupling method between the optical element and the optical fiber of the present embodiment, the same operational effects as the coupling structure and coupling method of the first embodiment are obtained.

  Furthermore, according to the coupling structure and coupling method between the optical element and the optical fiber according to the present embodiment, the clad 324 does not cover the core 322 at the end of the optical fiber 320 as shown in FIG. In other words, the core 322 and the clad 324 constitute a recess 360. Since the coupling portion 340 is provided in the recess 360, the coupling portion 340 can be reliably fixed. As a result, a bonded structure with a high yield can be obtained.

(Fifth embodiment)
FIG. 18 is a diagram schematically showing an optical module 5000 according to a fifth embodiment to which the present invention is applied. The optical module 5000 includes the optical element 10, the semiconductor chip 20, and the optical fiber 220 (see FIG. 8) of the third embodiment.

  As shown in FIG. 18, the optical module 5000 of the present embodiment includes a coupling structure including the optical element 10, the optical fiber 220, and the coupling unit 240. That is, the optical element 10 and the optical fiber 220 are joined via the coupling part 240.

  The optical module 5000 includes a coupling structure similar to the coupling structure (coupling unit 3000) of the third embodiment. Specifically, the optical fiber 220 and the coupling unit 240 (see FIG. 18) have the same configuration as that included in the coupling unit 3000 (see FIG. 8) of the third embodiment. Further, instead of the optical element 100 (see FIG. 8) included in the coupling unit 3000 of the third embodiment, an optical element 10 is installed in the optical module 5000 of the present embodiment as shown in FIG. Has been.

  In this optical module 5000, instead of the optical fiber 220, the optical fiber shown in the above-described modified example or other embodiments may be used.

1. Structure of Optical Module The optical element 10 may be a light emitting element or a light receiving element. As an example of the light emitting element, a surface light emitting element, in particular, a surface emitting laser can be applied. A surface emitting element such as a surface emitting laser emits light in a direction perpendicular to the substrate. The optical element 10 has an optical portion 12. When the optical element 10 is a light emitting element, the optical part 12 is a light emitting part, and when the optical element 10 is a light receiving element, the optical part 12 is a light receiving part. The optical portion 12 is provided with an optical surface 12a.

  The optical element 10 is joined to the optical fiber 220 via the coupling portion 240. The optical portion 12 is installed at a position facing the core 222 of the optical fiber 220. In the present embodiment, the optical portion 12 faces the hole 28 of the semiconductor chip 20.

  The optical element 10 has at least one (generally two or more) electrodes. For example, in the optical element 10, the first electrode 14 may be provided on the surface on which the optical portion 12 is formed. Note that at least one of the plurality of first electrodes 14 may be a dummy electrode. The dummy electrode may be formed of the same material as the first electrode 14, but is not electrically connected to the inside of the optical element 10. For example, the first electrode 14 may be formed at a position where all of them are connected by straight lines to draw a polygon more than a triangle, and at least one of them may be a dummy electrode. By doing so, the optical element 10 can be stably supported at three or more points.

  In the optical element 10, the second electrode 16 may be provided on a surface different from the surface on which the first electrode 14 is provided. When the optical element 10 is a semiconductor laser such as a surface emitting laser, the second electrode 16 may be provided on the surface of the optical element 10 opposite to the surface on which the first electrode 14 is provided.

  The semiconductor chip 20 is for driving the optical element 10. The semiconductor chip 20 includes a circuit for driving the optical element 10. The semiconductor chip 20 is formed with a plurality of electrodes (or pads) 22 electrically connected to an internal circuit. A wiring pattern 24 electrically connected to at least one electrode 22 is preferably formed on the surface on which the electrode 22 is formed.

  The semiconductor chip 20 and the optical element 10 are electrically connected. For example, the first electrode 14 of the optical element 10 and the wiring pattern 24 formed on the semiconductor chip 20 are electrically connected. For the connection, a wire or the like may be used. However, the first electrode 14 and the wiring pattern 24 are connected to each other through a metal bond or an anisotropic conductive material (film) using solder 26 as an example of a brazing material. You may join. In this case, the optical element 10 is mounted face down on the semiconductor chip 20. According to this configuration, not only electrical connection can be made by the solder 26, but also the optical element 10 and the semiconductor chip 20 can be fixed. Of the first electrodes 14, the one that becomes a dummy electrode is preferably bonded to the wiring pattern 24. By doing so, the optical element 10 can be fixed on the semiconductor chip 20 in a stable state.

  Further, the second electrode 16 of the optical element 10 and the wiring pattern 24 are electrically connected. For the connection, a wire 27 may be used, or a conductive paste may be provided from the second electrode 16 to the wiring pattern 24.

  An underfill material 40 may be provided between the optical element 10 and the semiconductor chip 20. The underfill material 40 covers and protects the electrical connection portion between the optical element 10 and the semiconductor chip 20 and also protects the surfaces of the optical element 10 and the semiconductor chip 20. Further, the underfill material 40 has a function of maintaining the bonding state between the optical element 10 and the semiconductor chip 20.

  Further, the underfill material 40 further has a function as a sealing material for fixing the gap between the coupling portion 240 and the optical fiber 220. The refractive index of the underfill material 40 is preferably smaller than the refractive index of the core 222 and the refractive index of the coupling portion 240 of the optical fiber 220. Thereby, the underfill material 40 can be provided with a function as a clad for confining light propagating in the core 222 and the coupling portion 240.

  Further, the refractive index of the coupling portion 240 is preferably the same as the refractive index of the core 222, and the refractive index of the underfill material 40 is more preferably the same as the refractive index of the cladding 224. That is, in this case, the same function as the core and the clad of the optical fiber can be imparted to the coupling portion 240 and the underfill material 40, respectively.

  A hole (for example, a through hole) 28 may be formed in the semiconductor chip 20. The optical fiber 220 in which the coupling portion 240 is installed on the end surface 222 a of the core 222 is inserted into the hole 28. The hole 28 is formed from the surface on which the electrode 22 is formed to the surface on the opposite side, avoiding an internal circuit. A taper 29 is preferably formed at at least one open end of the hole 28. By forming the taper 29, the optical fiber 220 can be easily inserted into the hole 28.

  The semiconductor chip 20 may be attached to the substrate 42. Specifically, the semiconductor chip 20 may be attached to the substrate 42 via the adhesive 44. A hole 46 is formed in the substrate 42. The hole 46 is formed at a position communicating with the hole 28 of the semiconductor chip 20. The adhesive 44 that bonds the semiconductor chip 20 and the substrate 42 is provided so as not to block the communication between the two holes 28 and 46. The hole 46 of the substrate 42 has a tapered shape so that the inner diameter increases in the direction opposite to the semiconductor chip 20. Thereby, it becomes easy to insert the optical fiber 220.

  The substrate 42 may be formed of an insulating material such as resin, glass, or ceramic, but may be formed of a conductive material such as metal. When the substrate 42 is made of a conductive material, it is preferable to form the insulating film 43 on at least the surface to which the semiconductor chip 20 is attached. Note that the same material can be used for the substrate 42 in the following embodiments.

  The substrate 42 preferably has high thermal conductivity. According to this, the substrate 42 promotes heat dissipation of at least one of the optical element 10 and the semiconductor chip 20. In this case, the substrate 42 is a heat sink or a heat spreader. In the present embodiment, since the semiconductor chip 20 is bonded to the substrate 42, the semiconductor chip 20 can be directly cooled. The adhesive 44 that bonds the semiconductor chip 20 and the substrate 42 preferably has thermal conductivity. Furthermore, since the semiconductor chip 20 is cooled, the optical element 10 bonded to the semiconductor chip 20 is also cooled.

  A wiring pattern 48 is provided on the substrate 42. The substrate 42 is provided with external terminals 50. In the present embodiment, the external terminal 50 is a lead. The wiring pattern 48 formed on the substrate 42 includes, for example, the electrode 22 of the semiconductor chip 20, the wiring pattern 24 formed on the semiconductor chip 20, the first or second electrode 14 of the optical element 10 via the wire 52, It is electrically connected to at least one of 16. Further, the wiring pattern 48 may be electrically connected to the external terminal 50.

  The optical fiber 220 is inserted into the hole 28 of the semiconductor chip 20. The optical surface 12 a of the optical element 10 faces the hole 28 of the semiconductor chip 20. Therefore, the optical fiber 220 inserted into the hole 28 is aligned with the optical surface 12a.

  The optical fiber 220 is also inserted into the hole 46 of the substrate 42. The inner diameter of the hole 46 gradually decreases toward the hole 28 of the semiconductor chip 20, and the inner diameter of the opening of the hole 46 is larger than that of the optical fiber 220 on the surface opposite to the semiconductor chip 20. . The gap between the optical fiber 220 and the inner surface of the hole 46 is preferably filled with a filler 54 such as resin. The filler 54 also has a function of fixing the optical fiber 220 and preventing it from coming off.

  In the present embodiment, the optical element 10 and the semiconductor chip 20 are sealed with a resin 56. The resin 56 also seals an electrical connection portion between the optical element 10 and the semiconductor chip 20 and an electrical connection portion between the semiconductor chip 20 and the wiring pattern 48 formed on the substrate 42.

2. According to the optical module 5000 of the present embodiment, the optical element 10 and the optical fiber 220 are joined via the coupling portion 240, so that a separate lens is provided between the optical fiber and the optical element. Compared with a general optical module, the apparatus can be simplified, reduced in size, and reduced in cost.

  Further, as compared with a general optical module in which a lens is separately provided between the optical fiber and the optical element, light is reliably transmitted between the optical element 10 and the optical fiber 220 via the coupling portion 240. be able to.

(Sixth embodiment)
FIG. 19 is a diagram showing an optical transmission apparatus according to an embodiment to which the present invention is applied. The optical transmission device 90 connects electronic devices 92 such as a computer, a display, a storage device, and a printer to each other. The electronic device 92 may be an information communication device. The optical transmission device 90 may be one in which plugs 96 are provided at both ends of the cable 94. The cable 94 can include a coupling structure (coupling unit 1000, see FIG. 1) of the optical element 100 and the optical fiber 120 of the first embodiment at one or both ends. The plug 96 incorporates the semiconductor chip 20. The attachment state of the optical fiber 120 and the optical element 100 or the semiconductor chip 20 is as described above. Instead of the coupling structure between the optical element 100 and the optical fiber 120 according to the first embodiment, the coupling structure according to the above-described modification or another embodiment may be used.

  The optical element 100 connected to one end of the optical fiber 120 is a light emitting element. The electrical signal output from one electronic device 92 is converted into an optical signal by the optical element 100 which is a light emitting element. The optical signal travels through the optical fiber 120 and is input to the other optical element 100. The other optical element 100 is a light receiving element, and an input optical signal is converted into an electric signal. The electric signal is input to the other electronic device 92. Thus, according to the light transmission device 90 of the present embodiment, information transmission of the electronic device 92 can be performed by an optical signal.

(Seventh embodiment)
FIG. 20 is a diagram showing a usage pattern of the optical transmission device according to the embodiment to which the present invention is applied. The optical transmission device 90 connects the electronic devices 80. As the electronic device 80, a liquid crystal display monitor or a digital CRT (may be used in the fields of finance, mail order, medical care, education), a liquid crystal projector, a plasma display panel (PDP), a digital TV, a retail store A cash register (for POS (Point of Sale Scanning)), a video, a tuner, a game device, a printer, and the like can be given.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the invention includes substantially the same configuration (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and result) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

It is a side view which shows typically the coupling structure of the optical element and optical fiber which concern on 1st Embodiment. It is a figure which shows typically 1 process of the coupling | bonding method of the optical element and optical fiber which concern on 1st Embodiment. It is a figure which shows typically 1 process of the coupling | bonding method of the optical element and optical fiber which concern on 1st Embodiment. It is a figure which shows typically 1 process of the coupling | bonding method of the optical element and optical fiber which concern on 1st Embodiment. It is a side view which shows typically the coupling structure of the optical element and optical fiber which concern on 2nd Embodiment. It is a figure which shows typically 1 process of the coupling | bonding method of the optical element and optical fiber which concern on 2nd Embodiment. It is a figure which shows typically 1 process of the coupling | bonding method of the optical element and optical fiber which concern on 2nd Embodiment. It is a side view which shows typically the coupling structure of the optical element and optical fiber which concern on 3rd Embodiment. It is a figure which shows typically an example of the manufacturing process of the optical fiber shown in FIG. It is a figure which shows typically an example of the manufacturing process of the optical fiber shown in FIG. It is a figure which shows typically 1 process of the coupling | bonding method of the optical element and optical fiber which concern on 3rd Embodiment. It is a figure which shows typically the modification of the coupling structure of the optical element and optical fiber which concern on 3rd Embodiment. It is a figure which shows typically the coupling | bonding method of the optical element and optical fiber which are the modifications shown in FIG. It is a figure which shows typically the modification of the coupling structure of the optical element and optical fiber which concern on 3rd Embodiment. It is a side view which shows typically the coupling structure of the optical element and optical fiber which concern on 4th Embodiment. It is a figure which shows typically 1 process of the coupling | bonding method of the optical element and optical fiber which concern on 4th Embodiment. FIG. 17A is a diagram schematically showing a modification of the coupling structure between the optical element and the optical fiber according to the first embodiment, and FIG. 17B is a diagram showing the first embodiment. It is a figure which shows typically another modification of the coupling structure of the optical element which concerns on, and an optical fiber. It is a figure which shows typically the optical module which concerns on 5th Embodiment to which this invention is applied. It is a figure which shows typically the light transmission apparatus which concerns on 6th Embodiment to which this invention is applied. It is a figure which shows typically the usage type of the optical transmission apparatus which concerns on 7th Embodiment to which this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Optical element, 12 Optical part, 12a Optical surface, 14 1st electrode, 16 2nd electrode, 20 Semiconductor chip, 21 Recessed part, 22 Electrode, 24 Wiring pattern, 26 Solder, 27 Wire, 28 Hole, 29 Taper , 32 tip surface, 40 underfill material, 42 substrate, 43 insulating film, 44 adhesive, 46 hole, 48 wiring pattern, 50 external terminal, 52 wire, 54 filler, 56 resin, 90 optical transmission device, 80, 92 Electronic device, 94 cable, 96 plug, 100 optical element, 110 inkjet head, 112 inkjet nozzle, 113 energy, 120, 220, 320 optical fiber, 120a end face of optical fiber, 122, 222, 322 core, 124, 224, 32 Clad, 130 columnar section, 140, 240, 340, 740, 940 coupling section, 140a, 140x, 140y, 840a coupling section precursor, 140b droplet, 180 optical surface, 213 ultraviolet light, 222a, 222b, 322a core end surface, 224a, 324a clad end face, 226 sealing material, 230 etchant, 232 liquid, 260 convex part, 360 concave part, 1000, 1100, 2000, 3000, 3100, 3200, 3300, 4000 coupling unit, 5000 optical module

Claims (27)

An optical element including a columnar part and having an optical surface on an upper surface of the columnar part;
Optical fiber,
An end face of the optical fiber and a joint joined to the optical surface;
A coupling structure of an optical element and an optical fiber. In claim 1,
A coupling structure of an optical element and an optical fiber, wherein at least a part of an end face of the optical fiber faces the optical surface. An optical element including a columnar part and having an optical surface on an upper surface of the columnar part;
An optical fiber including a core and a cladding;
A coupling portion joined to an end surface of the core and the optical surface;
A coupling structure of an optical element and an optical fiber. In claim 3,
A coupling structure of an optical element and an optical fiber, wherein at least a part of an end surface of the core faces the optical surface. In any of claims 1 to 4,
The coupling structure of the optical element and the optical fiber, wherein the refractive index of the coupling portion is substantially equal to the refractive index of the core of the optical fiber. In any of claims 1 to 5,
The coupling structure between the optical element and the optical fiber, wherein the refractive index of the coupling portion is larger than the refractive index of the cladding of the optical fiber. In any of claims 3 to 6,
At the end of the optical fiber joined to the coupling part,
A coupling structure of an optical element and an optical fiber, wherein the end face of the core and the end face of the clad are different in height. In claim 7,
In the end portion, the core is not covered with the clad, and is a coupling structure of an optical element and an optical fiber. In claim 8,
A coupling structure of an optical element and an optical fiber, in which a convex portion is formed by the core and the clad at the end portion. In any of claims 6 to 9,
A coupling structure of an optical element and an optical fiber in which the periphery of the coupling portion is covered with a sealing material at the end portion. In claim 10,
An optical element-optical fiber coupling structure in which a refractive index of the sealing material is smaller than a refractive index of a core of the optical fiber and a refractive index of the coupling portion. In claim 11,
The refractive index of the coupling portion is approximately equal to the refractive index of the core of the optical fiber,
A coupling structure between an optical element and an optical fiber, wherein a refractive index of the sealing material is substantially equal to a refractive index of a clad of the optical fiber. In claim 7,
In the end portion, the clad does not cover the core, and is a coupling structure of an optical element and an optical fiber. In claim 13,
A coupling structure of an optical element and an optical fiber, in which a concave portion is formed by the core and the clad at the end. In any one of Claims 1 thru | or 14.
The coupling portion is a coupling structure of an optical element and an optical fiber, which is formed by curing a liquid material that can be cured by applying energy. In claim 15,
The coupling portion is a coupling structure of an optical element and an optical fiber made of an ultraviolet curable resin. In any of claims 1 to 16,
The optical element is any one of a surface emitting semiconductor laser, a semiconductor light emitting diode, an EL device, and a photodiode, and a coupling structure of an optical element and an optical fiber. A coupling structure between the optical element according to any one of claims 1 to 17 and an optical fiber;
An optical module comprising: a semiconductor chip electrically connected to the optical element. Optical fiber,
A light emitting element including an emission surface, and causing light emitted from the emission surface to be incident on one end surface of the optical fiber;
A semiconductor chip electrically connected to the light emitting element;
A light receiving element that includes an incident surface and introduces light emitted from the other end surface of the optical fiber from the incident surface;
A semiconductor chip electrically connected to the light receiving element,
The coupling structure between the optical element and the optical fiber according to any one of claims 1 to 17, wherein at least one of the coupling structure between the light emitting element and the optical fiber and the coupling structure between the light receiving element and the optical fiber. An optical transmission device comprising: (A) discharging a droplet to at least one of the end face of the optical fiber and the optical surface of the optical element to form a coupling portion precursor;
(B) in a state where the end face of the optical fiber and the optical surface are bonded via the bonding portion precursor, the bonding body precursor is cured to form a bonding portion,
The method for coupling an optical element and an optical fiber, wherein the optical element includes a columnar portion, and the optical surface is provided on an upper surface of the columnar portion. In claim 20,
In (b), the end surface of the optical fiber and the optical surface are bonded via the coupling portion precursor in a state where at least a part of the end surface of the optical fiber is opposed to the optical surface. A method for coupling an optical element and an optical fiber. (A) discharging a droplet to at least one of the end surface of the core of the optical fiber and the optical surface of the optical element to form a coupling portion precursor;
(B) in a state where the end surface of the core and the optical surface are bonded via the bonding portion precursor, the bonding body precursor is cured to form a bonding portion,
The method for coupling an optical element and an optical fiber, wherein the optical element includes a columnar portion, and the optical surface is provided on an upper surface of the columnar portion. In claim 22,
(B) including joining the end surface of the core and the optical surface via the coupling portion precursor in a state where at least a part of the end surface of the core is opposed to the optical surface. A method of coupling an optical element and an optical fiber. In claim 22 or 23,
The method for coupling an optical element and an optical fiber, wherein the height of the end face of the core is different from the height of the end face of the clad. 25. Any one of claims 20 to 24.
The droplet is ejected by an ink jet method, which is a coupling method between an optical element and an optical fiber. In any of claims 20 to 25,
The coupling portion precursor is cured by adding energy, and is a method for coupling an optical element and an optical fiber. In any one of claims 20 to 26,
The optical element is any one of a surface emitting semiconductor laser, a semiconductor light emitting diode, an EL device, and a photodiode, and is a method for coupling an optical element and an optical fiber.

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