JP2005338782A - Optical receptacle with lens and optical module using the same - Google Patents

Abstract

An outer diameter of a fiber stub 25 is processed with extremely high precision so that cores (not shown) having a diameter of about 10 μm that propagate an optical signal formed at the center of an optical fiber 23 are connected with low loss. In addition, in order to directly bond the cores to each other, the curved surfaces must be mirror-polished.
A rod-shaped lens 6 and a distal end portion of a plug ferrule 2 in which an end portion of the rod-shaped lens 6 is inserted and fixed from one end portion and an optical fiber 1 is fixed to an axial center from the other end portion are inserted. The cylindrical sleeve 3 that abuts the distal end surface of the plug ferrule 2 and the distal end surface of the rod-shaped lens 6 and a through-hole, and the rear end portion of the rod-shaped lens 6 is gripped by the inner peripheral surface of the through-hole. The cylindrical lens holder 4 is included, and the rear end surface of the rod-shaped lens 6 is curved so as to have a condensing point on the front end surface of the optical fiber 1 at the front end portion of the plug ferrule 2.
[Selection] Figure 1

Description

  The present invention relates to an optical receptacle with a lens used for optical communication and an optical module using the same.

  An optical module for converting an optical signal into an electrical signal has a structure in which an optical element such as a semiconductor laser or a photodiode is housed in a case, and the optical signal is introduced or derived through an optical fiber. In addition, a receptacle-type optical module in which a connector is connected among optical modules has an optical element at one end of the optical receptacle and an optical connector plug ferrule having an optical fiber made of quartz glass or the like at the other end. (See Patent Document 1).

  A receptacle-type optical module in which a connector is connected among the optical modules includes an optical element 30 at one end of an optical receptacle 29 as shown in FIG. 10 and an optical fiber 21 made of quartz glass or the like at the other end. The optical connector plug ferrule 22 is connected.

  This optical receptacle 29 has a ferrule 24 made of a ceramic material such as zirconia or alumina, and a rear end portion of a fiber stub 25 obtained by inserting and fixing an optical fiber 23 made of quartz glass or the like in a through hole of the ferrule 24. 27 is fixed by press-fitting, and the tip portion is inserted into the inner hole of the sleeve 26, and they are press-fitted or adhesively fixed to the sleeve case 28.

  The end face of the optical fiber 23 in the fiber stub 25 is mirror-polished to a curved surface having a curvature radius of about 5 to 30 mm in order to reduce connection loss at the time of contact, and the opposite end face is emitted from the optical element 30 such as an LD. In order to prevent the reflected light from being reflected at the tip of the optical fiber 23 and returning to the optical element, the optical signal is mirror-polished on the inclined surface together with the ferrule 24.

  At this time, the outer diameter of the ferrule 24 is about φ2.5 mm for the type to which the SC connector is connected, about φ1.25 mm for the small type to which the LC connector is connected, and the outer diameter tolerance is ± 1 μm or less. The optical fiber 23 provided in the hole has an outer diameter of about 125 μm and an outer diameter tolerance of about ± 1 μm, which is defined by the JIS standard, the IEC standard, and the like. Conventionally, an optical signal formed at the center of the optical fiber 23 is used. Each core (sleeve 26, ferrule 24, etc.) is processed with high precision so that cores (not shown) having a diameter of about 10 μm that propagate through the core are connected with low loss. The connector plug ferrule 22 is held stably and with high accuracy.

  Further, when an optical module is configured using the optical receptacle 29 described above, a case 32 having an optical element 30 and a lens 31 is joined to the rear end surface side of the optical receptacle 29 having the fiber stub 25 by welding, and optical An optical connector plug ferrule 22 is inserted into the sleeve 26 from the other end face side of the receptacle 29, and the end faces of the optical fiber 23 and the optical fiber 21 are brought into contact with each other to exchange optical signals.

  Conventionally, an optical module using an optical receptacle as described above is used only for low-speed communication applications such as a LAN, and an optical module using an optical fiber pigtail is used for high-speed communication applications such as a trunk line system. It was done.

  However, in recent years, there has been a demand for higher communication speeds in LANs and the like, and optical modules using optical receptacles are much smaller than optical modules using optical fiber pigtails. There has also been a demand for higher communication speeds in the optical modules used.

The increase in communication speed leads to the use of a high-performance semiconductor laser. In order to obtain stable characteristics, it is necessary to prevent reflected return light, so an optical isolator must be inserted in the optical path. Therefore, as shown in FIG. 11, an optical receptacle in which an optical isolator is arranged has been devised. (See Patent Document 2)
The optical receptacle 29 has a ferrule 24 made of a ceramic material such as zirconia or alumina, and a rear end portion of a fiber stub 25 obtained by inserting and fixing an optical fiber 23 made of quartz glass or the like into a through hole of the ferrule 24. 27 is fixed by press-fitting, and the tip portion is inserted into the inner hole of the sleeve 26, and they are press-fitted or adhesively fixed to the sleeve case 28.

Further, an optical isolator element 33 composed of a polarizer, a Faraday rotator, and a polarizer is provided at the rear end face of the fiber stub 25, and a ring-shaped magnet 34 surrounds the optical isolator element 33 with a holder 27. It is fixed to the adhesive.
JP 2001-66468 A JP 2003-75679 A

 However, the outer diameter of the fiber stub 25 is processed with extremely high accuracy in order to make the cores (not shown) having a diameter of about 10 μm that propagate the optical signal formed at the center of the optical fiber 23 have a low loss. In addition, since the cores must be mirror-polished in order to directly join the cores, there is a problem that the processing is very troublesome.

  In general, the shape of a transceiver using an optical module using an optical receptacle is standardized, and when the modulation speed applied to the semiconductor laser is increased, the space required for the electric circuit for that is increased. In other words, in order to secure the space of the electric circuit, it is required to shorten the optical receptacle, but because there is a length necessary for polishing the both ends of the fiber stub 25 and holding the fiber stub 25, There is a limit to shortening the length.

  Further, the optical fiber 23 of the fiber stub 25 is generally made of quartz and the ferrule 24 is made of a ceramic material, and both are fixed with an adhesive. When the end face made of such a different material is polished, quartz is polished faster than the ceramic material, and the end face of the optical fiber 23 is recessed more than the end face of the ferrule 24. It is difficult and time-consuming. In addition, due to temperature changes such as heat cycle, there is a problem that the optical fiber 23 is further recessed and the optical fiber 22 does not come into contact even if the worst plug ferrule 22 is brought into contact therewith.

  Further, in the case of the receptacle 29 using the fiber stub 25, the lens 31 is designed so as to condense on the rear end face side of the fiber stub, but in order to reduce the change in light output due to the positional deviation after assembly, In general, it is assembled in a state where it is intentionally blurred, so that the shape of the spot formed on the rear end face side is disordered. Further, since the fiber stub 25 is fixed with an adhesive around the optical fiber 23 having a very short length, the light incident on the clad portion of the optical fiber 23 spreads and the tip of the fiber stub 25 spreads. Or the tip of the plug ferrule 22 with the optical fiber 21 fixed at the center of the shaft is reflected by the adhesive that fixes the optical fiber 25 to reach the tip of the fiber stub 25. When it is inserted and brought into contact with and gripped on the front end surface of the fiber stub 25, there is a problem that connection loss increases.

  In order to solve the above-mentioned problems, the present invention provides a rod-shaped lens and a tip of a plug ferrule in which a tip of the rod-shaped lens is inserted and fixed from one end and an optical fiber is fixed from the other end to the center of the axis. A cylindrical sleeve that abuts the distal end surface of the plug ferrule and the distal end surface of the rod-shaped lens, and a through hole, and grips the rear end portion of the rod-shaped lens by the inner peripheral surface of the through hole. A cylindrical lens holder, and the rear end surface of the rod-shaped lens is processed to be curved so as to have a condensing point on the front end surface of the optical fiber at the front end portion of the plug ferrule.

  Further, the present invention provides a cylindrical lens holder having a through-hole and holding a rod-shaped lens on the inner peripheral surface of the through-hole, and one end of the lens holder is bonded or press-fitted to one end face. A cylindrical sleeve and a tip end portion of a plug ferrule having an optical fiber fixed from the other end portion of the sleeve to the axial center is inserted, and the tip end surface of the plug ferrule faces the tip end surface of the plug ferrule. The rod-shaped lens can be brought into contact with the distal end surface of the rod-shaped lens, and the rear end surface of the rod-shaped lens is curved so as to have a condensing point on the distal end surface of the optical fiber of the plug ferrule.

  Further, the present invention inserts a rod-shaped lens and a distal end portion of a plug ferrule in which the distal end portion of the rod-shaped lens is inserted and fixed from one end portion and an optical fiber is fixed to the axial center from the other end portion, A cylindrical lens holder having a cylindrical sleeve that abuts the distal end surface of the plug ferrule and the distal end surface of the rod lens, and a through hole, and holding the rear end portion of the rod lens on the inner peripheral surface of the through hole A refractive index distribution type in which the refractive index is gradually changed from the axial center to the outer peripheral direction so that the rear end surface of the rod-shaped lens has a condensing point on the optical fiber front end surface of the plug ferrule. It is a lens.

  Further, the present invention provides a cylindrical lens holder having a through-hole and holding a rod-shaped lens on the inner peripheral surface of the through-hole, and one end of the lens holder is bonded or press-fitted to one end face. A cylindrical sleeve and a tip end portion of a plug ferrule having an optical fiber fixed from the other end portion of the sleeve to the axial center is inserted, and the tip end surface of the plug ferrule faces the tip end surface of the plug ferrule. The refractive index gradually increases from the axial center to the outer periphery so that the rear end surface of the rod-shaped lens has a condensing point at the optical fiber front end surface of the distal end portion of the plug ferrule. The present invention is characterized in that the gradient index lens is changed.

  Further, the rear end surface of the rod-shaped lens is processed into a flat surface, and the optical isolator element is bonded to the flat portion.

  In addition, an optical isolator element composed of a polarizer and a Faraday rotator is disposed on the rear end surface of the rod-shaped lens, and the optical isolator element and the lens holder are integrated. is there.

  The present invention also provides an optical module comprising a case having an optical element using the above-described optical receptacle with lens.

  As described above, according to the optical receptacle with a lens and the optical module of the present invention, by replacing the conventionally used fiber stub with a rod-shaped lens, the optical fiber tip of the conventional fiber stub and the optical fiber of the plug ferrule The contact accuracy with the tip is high because the condensing point by the rod-shaped lens comes to the tip of the optical fiber of the plug ferrule and the disturbance of the spot that can be made at the tip of the optical fiber can be reduced. The coupling efficiency of the optical receptacle can be sufficiently increased, the fiber stub that is difficult to process is unnecessary, the accuracy of the components used can be relaxed, and the optical receptacle with lens that simplifies the manufacturing process at a low price can be realized. And In addition, the entire optical path can be shortened, which contributes to shortening the entire module.

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

 FIG. 1 is a cross-sectional view showing an embodiment of an optical receptacle with a lens of the present invention (hereinafter sometimes simply referred to as “optical receptacle”), and FIGS. 2 and 3 are cross-sectional views of an optical module using the optical receptacle. is there.

 As shown in FIG. 1, the optical receptacle 7 of the present invention includes a rod-shaped lens 6, a sleeve 3, a lens holder 4, and a sleeve case 5, and the rear end of the rod-shaped lens 6 is located inside the cylindrical lens holder 4. It is configured by gripping with the peripheral surface and inserting the tip of the rod-like lens 6 into one end of the sleeve 3 and press-fitting or adhesively fixing them to the sleeve case 5.

  On the other hand, the distal end portion of the plug ferrule 2 with the optical fiber 1 fixed to the center of the shaft is inserted from the other end portion of the sleeve 3, and the distal end surface of the plug ferrule 2 and the distal end surface of the rod-shaped lens 6 are brought into contact with each other. Further, the rod-like lens 6 has a tip end surface 60 which is brought into contact with a plug ferrule 2 for an optical connector having the optical fiber 1 and is mirror-finished. As will be described later, the rod-shaped lens 6 is curved so that the rear end surface of the rod lens 6 has a condensing point on the optical fiber front end surface 1 a of the plug ferrule 2.

  Examples of the material of the rod-shaped lens 6 include inorganic materials such as glass and sapphire, and resin materials such as acrylic, polymethyl methacrylate (PMMA), and polyolefin. However, the material is not limited to these as long as the lens can be processed. In particular, it is preferable to use an inorganic material such as optical glass, synthetic quartz, silicon, or sapphire because it can be used at low cost and durability is maintained even when the contact of the plug ferrule 2 is repeated. In any case, since it is made of a single material, extreme unevenness does not occur on the distal end surface 60, and the distal end surface 1a of the optical fiber 1 is reliably rod-shaped when the plug ferrule 2 is brought into contact therewith. 6 tip surfaces 60 can be brought into contact with each other. The outer diameter of the rod-shaped lens 6 is about φ2.5 mm for the type connecting the SC connector and about φ1.25 mm for the small type connecting the LC connector.

  In the sleeve 3, as described above, not only the tip end of the rod-shaped lens 6 is inserted from one end, but also the plug ferrule 2 having the optical fiber 1 made of quartz glass or the like is inserted from the other open end. Configured to hold. Further, as the material of the sleeve 3, materials such as zirconia, alumina, and copper are used, but zirconia ceramic materials are currently used mainly considering wear resistance. The surface roughness of the inner diameter of the sleeve 3 is preferably Ra 0.2 μm or less in consideration of insertability.

  On the other hand, the sleeve case 5 is formed in a cylindrical shape, and one end side is formed with a convex portion for connector that facilitates removal of the plug ferrule 2, and the sleeve 3 can be accommodated therein. If the sleeve case 5 can be stably connected to the lens holder 4, it is not necessary to consider wear resistance and weldability, so the material is stainless steel, copper, iron, nickel, plastic, zirconia, alumina, etc. Although a wide range of materials are used, stainless steel is mainly used in the same manner as the lens holder 4 in order to increase the reliability by matching the thermal expansion coefficient with the lens holder 4.

 The lens holder 4 is formed in a bottomed cylindrical shape, and a through hole 40 is formed in the bottom surface thereof, and a sleeve case 5 integrated with the sleeve 3 is press-fitted or fitted into the bottomed cylinder. The rear end side of the rod-shaped lens 6 is press-fitted into the through hole 40 while being held together. Since the lens holder 4 is often welded to the case 10 that houses the optical element 11 shown in FIGS. 2 and 3 as an optical module, a material that can be welded such as stainless steel, copper, iron, or nickel is used. However, stainless steel is mainly used in consideration of corrosion resistance and weldability. Further, gold plating or the like may be applied to the outer surface in consideration of adhesion with solder.

  FIG. 2 is a cross-sectional view showing an embodiment in which an optical module is configured using the optical receptacle 7 of the present invention. The optical module 8 and the lens 10 are joined to the holder 4 to form a case 10.

  An optical connector (not shown) having a plug ferrule 2 generally uses a spring structure, and has a structure in which a constant load is continuously applied to the plug ferrule 2, more specifically, the distal end surface 1a of the optical fiber 1, It is fixed by bringing the end face of a fiber stub (not shown) used in the conventional structure into contact with the plug ferrule 2.

  On the other hand, the structure of the present invention does not have a fiber stub, and the plug ferrule 2 is positioned by abutting against the end face of the rod-shaped lens 6. The rod-shaped lens 6 is fixed by press-fitting into the through hole 40 of the lens holder 4 and can be sufficiently fixed even when a load is applied from the plug ferrule 2. Furthermore, as long as the strength equivalent to that of press-fitting can be obtained, it may be fixed by any one of solder, brazing material, low melting point glass, and adhesive. In addition, since the rod-shaped lens 6 has a refractive index close to that of the optical fiber 1, the core of the optical fiber 1 is directly connected to the rod-shaped lens 6, so that the loss due to reflection is very small.

  Here, in the case of a fiber stub conventionally used for the rod-shaped lens 6, the core of the optical fiber 1 held by the plug ferrule 2 and the core of the optical fiber held by the fiber stub are directly connected to each other. Therefore, a slight misalignment greatly affects the connection loss. Therefore, each part (sleeve, ferrule, etc.) needs to be processed with high precision and is very expensive. However, in the structure of the present invention, the light emitted when the optical element 8 is a semiconductor laser. After the optical signal passes through the lens 9 and becomes a parallel beam, it enters the rod-shaped lens 6. As described above, the end surface of the rear end portion of the rod-shaped lens 6 is processed into a curved surface, and the tip surface 1 a of the optical fiber 1 held by the optical connector plug ferrule 2, specifically, the core of the optical fiber 1. It passes through the optical path 20a to be coupled.

  When the optical module is assembled at the position where it can be coupled to the maximum, the optical signal that has passed through the lens 9 and the rod-shaped lens 6 is reduced to a spot size of about 10 μm near the end face of the optical fiber 1. If the positional fluctuation of only a few μm occurs, it will lead to fluctuation of the light output.

 Therefore, in general, a semiconductor laser is used which can obtain an output capable of satisfying a desired output with a coupling of 40 to 60%. By increasing the spot size of the optical fiber 1 with respect to the core (not shown) of the optical fiber 1, it is assembled so as to reduce the fluctuation of the optical output with respect to the fluctuation of the position. be able to. Therefore, according to the configuration of the present invention, the processing accuracy of the rod-shaped lens 6, the sleeve 3, and the plug ferrule 2 can be relaxed.

 In the configuration of the present invention, since the fiber stub is not used, there is no influence of the spread of light incident on the clad portion of the optical fiber or the light reflected on the adhesive fixing the optical fiber. Even if the spot size near the end face is intentionally increased, it is possible to create a shape with less disturbance than when using a fiber stub, thereby reducing coupling efficiency and non-uniform output fluctuation due to spot disturbance. Can do.

 On the other hand, when the optical element 8 is a photodiode, light is emitted from the optical fiber 1 and is condensed on the optical element 8 through the optical path 20a. However, when the component accuracy is reduced as described above, the position of the optical element 8 is reduced. The spot size at will increase. However, the photodiode has a light receiving width of at least several tens of μm, and the component accuracy is relaxed rather than in the case of a semiconductor laser.

  Furthermore, when the total length of the optical module is considered, an optical path to the optical element 8 and the end face of the optical fiber 1 is required. When a conventional fiber stub is used, the fiber stub propagates through the optical fiber while the light passes through the fiber stub. Must be added to the optical path, but there is a limit to shortening the length of the fiber stub because there is a length necessary for polishing both ends of the fiber stub and holding the fiber stub.

  However, in the structure of the present invention, since the end face of the optical fiber 1 is a light emission position, the entire optical path can be shortened as compared with the fiber stub, and as a result the short length of the optical module can be reduced. Can be realized.

 As described above, by replacing the conventional fiber stub with a rod-shaped lens, a fiber stub that is difficult to process is unnecessary, and the precision of the parts used can be relaxed. An optical receptacle can be realized. In addition, the entire optical path can be shortened, which can contribute to shortening the entire optical module.

  FIG. 3 is a cross-sectional view showing another embodiment in which an optical module is configured using the optical receptacle 7 of the present invention. The difference from the configuration of FIG. 2 is that the lens 9 is omitted and the rod-shaped lens 6 is used. Either the radius of curvature of the rear end surface of the rod-shaped lens 6 is reduced or the refractive index of the material is increased so that the optical path 20b having a condensing point can be passed through the optical fiber tip 1a of the plug ferrule. This is a change. According to this configuration, the optical path length can be shortened more than the configuration of FIG. 2, and the optical module can be further shortened.

  FIG. 4 is a cross-sectional view showing another embodiment of the optical receptacle with a lens according to the present invention. The lens holder 4 has a sleeve case, is composed of a rod-shaped lens 6, a precision sleeve 71, and a holder 4, and has a through hole. The rod-shaped lens 6 is fixed to the inner peripheral surface of the lens, and the precision sleeve 71 is fixed to one end surface of the lens holder 4 by bonding or press-fitting. According to this configuration, since the tip of the rod-shaped lens 6 is not inserted into one end of the sleeve 71, the rod-shaped lens 6 can be made shorter and the module can be made shorter. In addition, since the precision sleeve 71 escapes the air at the time of insertion, it is more desirable to use the thing of a multipoint support.

  FIG. 5 is a cross-sectional view showing another embodiment of the optical receptacle with lens according to the present invention. As a rod-like lens of the receptacle 7 with lens, a refractive index distribution type in which the refractive index is gradually changed from the axial center to the outer peripheral direction. The lens 16 is used. Such a refractive index distribution type lens 16 is generally called a GRIN (Graded Index) lens, and indicates a lens whose refractive index distribution is axisymmetric with respect to the central axis of the lens and has a square distribution. . The paraxial region has optical characteristics similar to those of a normal spherical lens. However, by setting the lens length and the refractive index distribution, the focal position and the condensing position can be changed to the desired positions. Therefore, if the tip surface 1a of the optical fiber 1 is designed to have a condensing point, it can have the same function as the rod-shaped lens 6 included in the optical receptacle shown in FIGS. Then, the processing applied to the end surface of the rear end portion of the rod-shaped lens 16 becomes processing that does not require the curved surface processing applied to the rear end surface of the rod-shaped lens 6 included in the optical receptacle shown in FIGS. Contributes to shortening and cost reduction of optical modules.

  FIG. 6 is a cross-sectional view showing another embodiment of the optical receptacle with lens according to the present invention. The sleeve case is eliminated, the refractive index distribution type lens 16, the precision sleeve 71, and the lens holder 4 are formed. The gradient index lens 16 is fixed to the inner peripheral surface of the lens holder 4 and the precision sleeve 71 is fixed to one end surface of the lens holder 4 by bonding or press-fitting. According to this configuration, since the tip end portion of the gradient index lens 16 is not inserted into one end portion of the sleeve 71 as in FIG. 4, the gradient index lens 16 can be further shortened, and the optical module Can be made shorter.

 FIG. 7 is a cross-sectional view showing another embodiment of the optical receptacle with lens of the present invention. The rear end surface of the gradient index lens 16 of the optical receptacle 7 shown in FIG. A structure in which the optical surface of the polarizer 11b of the optical isolator element 13 formed by bonding the optical surfaces of the Faraday rotator 12 to each other between the two polarizers 11a and 11b is bonded to the end surface with an adhesive. is there.

  FIG. 8 is a cross-sectional view showing another embodiment of the optical receptacle with a lens of the present invention, and is configured by bonding each optical surface of the Faraday rotator 12 between two polarizers 11a and 11b. In order to apply a magnetic field to the isolator element 13 and the Faraday rotator 12, a cylindrical magnet 14 is fixed to the optical isolator holder 15, and the optical isolator holder 15 and the lens holder 7 of the optical receptacle 7 are connected to each other by YAG laser, soldering, and bonding. It is configured to be integrated with an agent or the like.

 The polarizers 11a and 11b are reflective polarizations that use a diffraction grating or the like in addition to a polarizer that absorbs a polarization component orthogonal to the transmission polarization direction, such as a type in which dielectric particles are included in a glass substrate or a dielectric layered type. A birefringent crystal that shifts the optical path and the optical element can also be used. Further, the Faraday rotator 12 used in the optical isolator element 13 can be configured as a Bi-substituted garnet or YIG garnet added with Tb, Gd, or Ho, or a self-bias type that does not require a magnet. With this configuration, in addition to obtaining the effect of the receptacle with a lens of the present invention, it becomes possible to prevent reflected return light returning to the semiconductor laser, so that a high-performance semiconductor laser can be used with stable characteristics, A semiconductor laser module with an increased communication speed can be realized.

 The structure of FIG. 7 has a shorter overall length than the structure of FIG. 8, and the optical isolator element 13 is disposed at a position where the beam is more narrowed, so that the element size can be reduced. Become.

  In the following, in the optical receptacle 7 prototyped based on the embodiment of the present invention shown in FIG. 1 and the optical receptacle 29 prototyped based on the conventional configuration shown in FIG. The coupling efficiency with the laser 8 was verified.

  In the optical receptacle 7 based on the embodiment of the present invention shown in FIG. 1, the rod-shaped lens 6 is made of optical glass BK7 (borosilicate crown glass), the lens holder 4 is stainless steel, and both are fixed by press fitting. The lens holder 4 and the sleeve case 5 were press-fitted and fixed using zirconia for the sleeve 3 for holding the optical connector plug ferrule 2 and stainless steel for the sleeve case 5.

 First, the semiconductor laser 8 and the lens 9 are fixed to the case 10, a large-diameter photodetector is disposed on the end surface of the case 10, the semiconductor laser 8 emits light so that the light intensity becomes about 1 mW, and the lens 9 is attached. The transmitted light intensity was measured with the photodetector.

 Next, as shown in FIG. 2, after the optical connector plug ferrule 2 is inserted into the optical receptacle 7, the light from the semiconductor laser 8 is transmitted through the lens 9 and the rod-shaped lens 6 to the front end surface of the rod-shaped lens 6. The case 10 and the optical receptacle 7 were fixed so as to collect light on the end face of the optical fiber 1 of the optical connector plug ferrule 2 facing the surface. Then, the light incident on the end face of the optical fiber 1 passes through the optical fiber 1, the light intensity emitted from the end face of the other optical fiber 1 is measured, and the light intensity and the light transmitted through the lens 9 measured above are transmitted. The ratio with the strength was calculated as the binding efficiency. The coupling efficiency was calculated as a percentage of the light intensity emitted from the end face of the other optical fiber 1 with respect to the light intensity transmitted through the lens 9. The result is shown in FIG.

 As a comparative example, the conventional optical receptacle with an optical isolator shown in FIG. 10 was made as a prototype, and the coupling efficiency was obtained by the same method as shown in FIG.

  Each of the measured samples is 45 samples, but all of the optical receptacles 7 according to the embodiment of the present invention can obtain a coupling efficiency of about 60%, and a coupling efficiency equivalent to that of the conventional optical receptacle 29 with an optical isolator is obtained. It was confirmed that

It is sectional drawing which shows one Embodiment of the optical receptacle with a lens of this invention. It is sectional drawing which shows the optical module using the optical receptacle with a lens of this invention. It is sectional drawing which shows the other optical module using the optical receptacle with a lens of this invention. It is sectional drawing which shows other embodiment of the optical receptacle with a lens of this invention. It is sectional drawing which shows other embodiment of the optical receptacle with a lens of this invention. It is sectional drawing which shows other embodiment of the optical receptacle with a lens of this invention. It is sectional drawing which shows other embodiment of the optical receptacle with a lens of this invention. It is sectional drawing which shows other embodiment of the optical receptacle with a lens of this invention. It is a figure which shows the result of having measured the coupling efficiency of the plug ferrule for optical connectors and a semiconductor laser in this invention and the conventional optical receptacle with an optical isolator. It is sectional drawing which shows the conventional optical receptacle type | mold optical module. It is sectional drawing which shows the conventional optical receptacle with an optical isolator.

Explanation of symbols

1: optical fiber 2: optical connector plug ferrule 3: sleeve 4: lens holder 5: sleeve case 6: rod lens 7: optical receptacle 8: semiconductor receptacle 9: lens 10: case 11a, 11b: polarizer 12: Faraday rotation Child 13: Optical isolator element 14: Magnet 15: Optical isolator holder 16: Gradient index lens 20a, 20b: Optical path 21: Optical fiber 22: Plug ferrule for optical connector 23: Optical fiber 24: Ferrule 25: Fiber stub 26: Sleeve 27: Stub holder 28: Sleeve case 29: Optical receptacle 30: Semiconductor laser 31: Lens 32: Case 33: Optical isolator element 34: Magnet 60: Tip surface 71 of rod-shaped lens: Precision sleeve

Claims (7)

A rod-shaped lens, and a distal end portion of the rod-shaped lens, the distal end portion of the plug ferrule is inserted and fixed from one end portion, and the distal end portion of the plug ferrule in which the optical fiber is fixed to the axial center from the other end portion; A cylindrical sleeve that abuts the tip surface of the rod-shaped lens, and a cylindrical lens holder that has a through-hole and grips the rear end of the rod-shaped lens on the inner peripheral surface of the through-hole, An optical receptacle with a lens, wherein a rear end surface of the rod-shaped lens is curved so as to have a condensing point on an optical fiber front end surface of the end portion of the plug ferrule. A cylindrical lens holder having a through-hole and holding a rod-shaped lens on the inner peripheral surface of the through-hole, and a cylindrical sleeve having one end bonded or press-fitted to one end face of the lens holder; A tip end of a plug ferrule having an optical fiber fixed to the center of the axis from the other end of the sleeve is inserted, and a tip end surface of the plug ferrule is connected to a tip end surface of a rod-shaped lens facing the tip end surface of the plug ferrule. An optical receptacle with a lens, which is capable of abutting and has a curved surface processed so that a rear end surface of the rod-shaped lens has a condensing point on an optical fiber front end surface of the plug ferrule. A rod-shaped lens, and a distal end portion of the rod-shaped lens, the distal end portion of the plug ferrule is inserted and fixed from one end portion, and the distal end portion of the plug ferrule in which the optical fiber is fixed to the axial center from the other end portion; A cylindrical sleeve that abuts the tip surface of the rod-shaped lens, and a cylindrical lens holder that has a through-hole and grips the rear end of the rod-shaped lens on the inner peripheral surface of the through-hole, A refractive index distribution type lens in which the refractive index is gradually changed from the axial center to the outer peripheral direction so that the rear end surface of the rod-shaped lens has a condensing point at the optical fiber front end surface of the plug ferrule tip. An optical receptacle with a lens. A cylindrical lens holder having a through-hole and holding a rod-shaped lens on the inner peripheral surface of the through-hole, and a cylindrical sleeve having one end bonded or press-fitted to one end face of the lens holder; A tip end of a plug ferrule having an optical fiber fixed to the center of the axis from the other end of the sleeve is inserted, and a tip end surface of the plug ferrule is connected to a tip end surface of a rod-shaped lens facing the tip end surface of the plug ferrule. Refractive index distribution in which the refractive index is gradually changed from the axial center to the outer peripheral direction so that the rear end surface of the rod-shaped lens has a condensing point on the optical fiber front end surface of the plug ferrule. Optical receptacle with lens, characterized by being a mold lens. The optical receptacle with a lens according to claim 3 or 4, wherein a rear end surface of the rod-shaped lens is processed into a flat surface, and the optical isolator element is bonded to the flat portion. 6. An optical isolator element constituted by a polarizer and a Faraday rotator is disposed on a rear end face of the rod-shaped lens, and the optical isolator element and a lens holder are integrated. An optical receptacle with a lens according to any one of the above. An optical module comprising a case having an optical element using the optical receptacle with a lens according to claim 1.

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