CN103576243B - Array micro electro mechanical variable optical attenuator - Google Patents

Abstract

The invention provides an array microelectromechanical variable optical attenuator. The array-type micro-electromechanical variable optical attenuator uses a combination of a fixed shading plate and a movable shading block to effectively control light scattering and beam size, and achieve good light attenuation performance.

Description

Array MEMS Variable Optical Attenuator

technical field

The invention relates to the field of optoelectronic technology, in particular to an array type micro-electromechanical variable optical attenuator.

Background technique

Variable optical attenuator (Variable Optical Attenuator, referred to as VOA), as an important passive optical power adjustment device, can produce controllable attenuation in the optical network, and can be combined with other devices to achieve flat optical gain and dynamic gain. Balance and transmission power equalization, etc., have a wide range of applications in wavelength division multiplexing (WDM) systems1.

VOA has many different types of manufacturing technologies, mainly including adjustable mechanical technology, magneto-optical technology, liquid crystal technology, acousto-optic technology, thermo-optic technology, planar waveguide technology, MEMS technology and other forms. Devices based on MEMS technology are small in size, good in performance, easy to implement arrays, and low in power consumption, meeting the needs of market development. VOA made with MEMS technology, in addition to maintaining the optical performance of traditional technology VOA, also has the advantages of large attenuation range, small size, easy multi-channel integration, fast response speed, and high cost performance. It is considered to be ideal for future all-optical communication networks. One of the devices.

The basic principle of MEMS VOA is that a MEMS movable structure drives the movement of the micro-mirror or visor. According to different driving methods, MEMS VOA has electrostatic, electromagnetic, electrothermal, piezoelectric and hybrid driving methods. Since the 1990s, various forms of MEMS VOAs have been extensively studied, and the techniques used have been continuously updated.

One of the key problems to be solved in the practical application of optical networks is the unbalanced power among wavelength channels. In many cases, it is necessary to reduce the power of optical signals. With the application of wavelength division multiplexing (WDM) in optical communication, gain flattening or channel power equalization must be performed on multiple optical signal transmission channels before the optical amplifier to prevent the input power of one or some channels from being too high. Large, causing the gain saturation of the optical amplifier. Large-scale optical attenuator arrays are required in fields such as hardware-in-the-loop imaging to achieve more precise imaging control.

However, although there are many reports on MEMS VOA, the research direction is mainly focused on a single device, and there are relatively few related studies on array-type variable optical attenuators, and no practical array-type MEMS variable optical attenuators have been proposed.

Contents of the invention

(1) Technical problems to be solved

In view of the above technical problems, the present invention provides an array micro-electromechanical variable optical attenuator.

(2) Technical solutions

According to one aspect of the present invention, an array micro-electromechanical variable optical attenuator is provided. The array microelectromechanical variable optical attenuator includes: a fixed shading plate, a controllable shading plate, a magnetic field generating device and a driving circuit. Wherein, the fixed shading plate has a light hole array in its central area, including several fixed light holes. The controllable shading plate is bonded under the fixed shading plate, and its central area has a movable shading block array corresponding to the light hole array, and each movable shading block unit in the movable shading block array includes: a movable shading block The blocks are suspended in the air, facing the corresponding fixed light holes, and connected to the substrate through elastic beams on both sides. The magnetic field generating device is located below or above the controllable shading plate, or on the periphery of the controllable shading plate, and is used to generate an axial magnetic field perpendicular to the plane where the fixed shading plate and the controllable shading plate are located. The drive circuit is electrically connected to the elastic beams of each movable light-shielding block unit in the movable light-shielding block array through metal leads. Wherein, each optical fiber in the input optical fiber array is inserted into the fixed optical hole corresponding to the fixed optical hole array, the output optical fiber array is located below the controllable light-shielding plate, and each optical fiber is aligned with each optical fiber of the input optical fiber array; For each movable shading block unit in the controllable shading plate, driven by the drive circuit, the elastic beam of the controllable shading plate passes a current, and the action of the current and the axial magnetic field generates a Lorentz force. Under the force, the elastic beam will deform, so that the corresponding movable shading block moves near the equilibrium position, thereby changing the luminous flux from the input fiber entering the corresponding output fiber through the corresponding light hole on the fixed shading plate and the movable shading block .

(3) Beneficial effects

It can be seen from the above technical solutions that the array type MEMS variable optical attenuator of the present invention has the following beneficial effects:

(1) By using the method of combining the fixed shading plate and the movable shading block, the light scattering and beam size are effectively and lowly controlled, and good light attenuation performance is achieved;

(2) Each unit adopts a parallel structure, and through current control, each unit of the array can change the moving state independently or synchronously, providing a basis for large-scale application of the device;

(3) A movable shading block structure and lead arrangement scheme are proposed, which greatly improves the space utilization of the chip, and the entire array can work reliably under the control of an integrated circuit.

Description of drawings

1A is a schematic cross-sectional view of an array micro-electromechanical variable optical attenuator according to an embodiment of the present invention;

Fig. 1B is a perspective view of the controllable light-through hole in the controllable shading plate of the array microelectromechanical variable optical attenuator shown in Fig. 1;

FIG. 2A is a top view of a fixed light-shielding plate in the array microelectromechanical variable optical attenuator shown in FIG. 1;

2B is a schematic cross-sectional view of a fixed light-shielding plate in the array-type MEMS variable optical attenuator shown in FIG. 1;

Fig. 3A is a top view of the controllable shading plate in the array microelectromechanical variable optical attenuator shown in Fig. 1;

3B is a schematic cross-sectional view of the controllable light-shielding plate in the array microelectromechanical variable optical attenuator shown in FIG. 1;

Fig. 3C is an enlarged view of the circuit connection relationship of the controllable light hole array in a certain area of the controllable light shielding plate shown in Fig. 3A and Fig. 3B;

FIG. 4 is a schematic diagram of the working principle of the array type MEMS variable optical attenuator shown in FIG. 1 .

[Description of the main component symbols of the present invention]

100-input fiber array;

200 - fixed visor;

210-light hole array; 211-fixed light hole;

230-bonding area;

300-controllable visor;

310-movable shading block array; 320-metal lead area;

330-bonding area; 311b-movable shading block;

311c-elastic beam; 331-control line;

332-ground wire; 333-anchor point;

400- output fiber array;

500-magnetic field generating device;

510 - Binder.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be noted that, in the drawings or descriptions of the specification, similar or identical parts all use the same figure numbers. Implementations not shown or described in the accompanying drawings are forms known to those of ordinary skill in the art. Additionally, while illustrations of parameters including particular values may be provided herein, it should be understood that the parameters need not be exactly equal to the corresponding values, but rather may approximate the corresponding values within acceptable error margins or design constraints. The directional terms mentioned in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", etc., are only referring to the directions of the drawings. Therefore, the directional terms used are for illustration and not for limiting the protection scope of the present invention.

The invention provides an array type micro-electromechanical variable optical attenuator driven by Lorentz force. The array-type micro-electromechanical variable optical attenuator is manufactured by MEMS technology, and the combination of the fixed shading plate and the movable shading block realizes good light attenuation performance.

In an exemplary embodiment of the present invention, an array type MEMS variable optical attenuator is provided. Fig. 1A is a schematic cross-sectional view of an array-type micro-electro-mechanical variable optical attenuator according to an embodiment of the present invention; Perspective view of the shading block unit. Please refer to FIG. 1A and FIG. 1B , the array microelectromechanical variable optical attenuator includes: a fixed shading plate 200 , a controllable shading plate 300 , a magnetic field generating device 500 and a driving circuit. Wherein, the fixed light-shielding plate 200 has a light hole array 210 in its central area, including several light holes, and each optical fiber in the input fiber array 100 is inserted into the corresponding fixed light hole of the fixed light hole array 210 . The controllable shading plate 300 is bonded under the fixed shading plate 200, and its central area has a movable shading block array 310 with elastic beams. Each movable shading block unit 311 in the movable shading block array includes: The movable light-shielding block 311b is suspended in the air, facing the corresponding fixed light-through hole, which is connected to the substrate through the elastic beams 311c on both sides, and the elastic beams 311c are electrically connected to the drive circuit through the metal leads on the device ; Wherein, the output fiber array 400 is located below the controllable light-shielding plate, and each optical fiber thereof is respectively aligned with each optical fiber of the input optical fiber array. The magnetic field generating device 500 is located below or above the controllable shading plate, or on the periphery of the controllable shading plate, and is used to generate an axial magnetic field perpendicular to the plane where the fixed shading plate 200 and the controllable shading plate 300 are located. The drive circuit is used to provide a controllable current to make the variable optical attenuator array switch in different attenuation states.

Wherein, for each movable shading block unit in the controllable shading plate, driven by the driving circuit, the elastic beam of the controllable shading plate passes a current, and the current interacts with the axial magnetic field to generate Loren Under the action of Lorentz force, the elastic beam will deform, so that the corresponding movable shading block moves near the equilibrium position, thereby changing the input optical fiber through the corresponding light hole on the fixed shading plate, the movable shading block Block the luminous flux entering the corresponding output fiber.

Each component of the array micro-electromechanical variable optical attenuator of this embodiment will be described in detail below.

fixed visor

FIG. 2A is a top view of a fixed light-shielding plate in the array microelectromechanical variable optical attenuator shown in FIG. 1 . FIG. 2B is a schematic cross-sectional view of a fixed light-shielding plate in the array-type MEMS variable optical attenuator shown in FIG. 1 .

Please refer to FIG. 2A and FIG. 2B , the fixed light-shielding plate 200 is made of a circular substrate with a light hole array 210 at its center. On both sides of the fixed light hole array 210, there are holes reserved for the driving circuit. The periphery is the bonding area 230 bonded with the controllable light-shielding plate 300 .

In the light hole array of the fixed light-shielding plate, the fixed light hole 211 is a structure with a wide top and a narrow bottom. The wider opening is convenient for optical fiber installation; the narrower end of the light hole is related to the size of the beam, which ensures the normal passage of the light beam. In addition, the divergence of light can be limited, so that the area where the light beam irradiates on the controllable shading plate 300 is minimized, thereby facilitating the work of the shading unit in the controllable shading plate.

Controllable visor

FIG. 3A is a top view of the controllable light-shielding plate in the array MEMS variable optical attenuator shown in FIG. 1 . 3B is a schematic cross-sectional view of the controllable light-shielding plate in the array MEMS variable optical attenuator shown in FIG. 1 . FIG. 3C is an enlarged view of the circuit connection relationship of the light-through holes in a certain area of the controllable light-through-hole array on the controllable shading plate shown in FIG. 3A and FIG. 3B .

Referring to FIG. 3A , the controllable shading plate 300 is fabricated on the SOI wafer substrate using MEMS technology, and its shape and size correspond to the fixed shading plate. The central area of the controllable shading plate 300 is a movable shading block array 310 . Around the movable light-shielding block array 310 is a metal lead area 320 . On the periphery of the entire controllable light-shielding plate 300 is a bonding area 330 bonded to the fixed light-shielding plate 200 , that is, the fixed light-shielding plate 200 and the controllable light-shielding plate 300 are integrated by bonding, and a bonding layer 230 is formed between them.

Please refer to Fig. 3A and Fig. 3B, the central area of the controllable shading plate 300 has an array of movable shading blocks, each movable shading block unit includes: The apertures are aligned and have a diameter larger than that of the fixed apertures; they are connected to the substrate through elastic beams 311c on both sides, and the elastic beams 311c are electrically connected to the driving circuit through metal interconnection wires. Wherein, the output optical fiber array 400 is located below the controllable light-shielding plate, and each optical fiber is aligned with the corresponding fixed light-through hole on the fixed light-shielding plate through the light-through hole body.

In the present invention, the fixed light hole is square, circular or triangular in shape, and its size is related to the size of the light beam, usually in the range of 1 micron to 500 microns, and the movable light-shielding block is a corresponding square, circular or triangular shape. and other shapes, and its size is slightly larger than the fixed light hole by a few microns to tens of microns. In addition, in order to make the entire controllable aperture array work normally under the voltage and current provided by the integrated circuit and reduce the power consumption of the device, it is necessary to reasonably design the device connection to minimize the working current and prevent the resistance from being too large.

As shown in Figure 3A and Figure 3C, the metal lead area 330 is located on the periphery of the controllable light-shielding plate array, including control lines 331, ground lines 332, and anchor points 333; the anchor points 333 are used for electrical interconnection with the control circuit by pressure welding.

As shown in FIG. 3A , in order to effectively utilize the blank space of the array substrate of the controllable light-shielding plate, the metal interconnection lines are arranged in the supporting area of the device unit. Under the premise of ensuring the electrical reliability of the lead wires without mutual influence, the width of the lead wires should be increased as much as possible and the length should be reduced. By making the ground wires 332 into a network structure, all the ground wires 332 are connected in parallel, which effectively reduces the resistance. These designs not only save space, but also reduce the total resistance, meet the working requirements of the driving circuit, and improve the performance of the entire variable optical attenuator array.

Referring to FIG. 2A and FIG. 3A , the bonding area 230 on the periphery of the fixed shading plate and the bonding area 330 on the periphery of the controllable shading plate are integrated by bonding for packaging. Those skilled in the art should be clear that, in addition to bonding, the fixed shading plate and the controllable shading plate can also be combined in other ways, as long as the fixed light hole of the fixed shading plate and the controllable light hole of the controllable shading plate are guaranteed Align the middle shading unit.

magnetic field generator

In this embodiment, the magnetic field generating device 500 is located below the controllable shading plate 300, but the present invention is not limited thereto. Periphery, etc., as long as it can generate an axial magnetic field perpendicular to the plane where the fixed shading plate 200 and the controllable shading plate 300 are located, and does not block the light path.

In this embodiment, the magnetic field generating device 500 is an annular permanent magnet, which is glued together with the lower surface of the controllable shading plate by an adhesive, so as to generate A planar axial magnetic field, but the field is not limited thereto, and the magnetic field generating device 500 may also use electromagnetic coils or other structures capable of generating an axial magnetic field.

Drive circuit

In this embodiment, the driving circuit is located above the controllable shading plate and in the reserved hole of the fixed shading plate, and is used to provide a controllable current to switch the variable optical attenuator array under different attenuation states. The driving circuit is a CMOS integrated circuit, and is integrated with the controllable shading plate 300 by bonding, pressure welding or other techniques.

Please refer to Fig. 1B and Fig. 4, the working principle of the array microelectromechanical variable optical attenuator of the present embodiment is as follows: for each movable shading block unit 311 in the controllable shading plate 300, When a current passes through the elastic beam 311c, the action of the current and the magnetic field generates a Lorentz force, and the Lorentz force is proportional to the magnitude of the current. Under the action of Lorentz force, the elastic beam 311c will be deformed, so that the corresponding movable shading block 311b will move near the equilibrium position, thus changing the input optical fiber through the corresponding light hole on the fixed shading plate, the movable shading block The light flux entering the corresponding output fiber realizes the control of light attenuation.

As shown in Figure 4, under the control of the driving current, each shading unit of the controllable aperture array can not only work independently of each other to achieve different light attenuation, but also all the shading units can change their working states at the same time. The first path shown in Figure 4 works in the state where the light is completely attenuated, the second path works in the state where the light is completely passed, and the third and fourth paths work in the state where the light is partially attenuated by current control The current passing through the device realizes the transition between different working states.

So far, the present embodiment has been described in detail with reference to the drawings. Based on the above description, those skilled in the art should have a clear understanding of the array type MEMS variable optical attenuator of the present invention.

In addition, the above-mentioned definitions of each element and method are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those skilled in the art can easily and well-known replace them, for example:

(1) The controllable light-shielding plate can be made not only by SOI substrate, but also by silicon wafer or other substrates;

(2) The fixed light-through hole on the fixed shading plate and the movable shading block on the controllable shading plate can be replaced by other shapes such as circles and triangles in addition to square shapes.

To sum up, the present invention provides an array-type micro-electromechanical variable optical attenuator prepared by MEMS technology. The array micro-electromechanical variable optical attenuator uses the Lorentz force to control the movement of the shading unit, so that the combination of the fixed shading plate and the movable shading block achieves good light attenuation performance, and has the advantages of large scale, good uniformity, and low cost. Low cost and other advantages, can be well compatible with IC, has huge market potential.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. an array micro electro mechanical variable optical attenuator, is characterized in that, comprising:

Fixing shadow shield, its central area has light hole array, comprises several fixing light holes;

Controlled shadow shield, be bonded to the below of described fixing shadow shield, its central area has the movable light shield block array corresponding with described light hole array, each movable light shield module unit in this movable light shield block array comprises: movable light shield block, unsettled setting, just to the fixing light hole of its correspondence, be connected to substrate by the elastic beam being positioned at both sides;

Magnetic field generation device, is positioned at below or the top of described controlled shadow shield, or the periphery of controlled shadow shield, for generation of the axial magnetic field perpendicular to described fixing shadow shield and controlled shadow shield place plane;

Driving circuit, is electrically connected the elastic beam of each the movable light shield module unit movable light shield block in described movable light shield block array respectively by metal lead wire;

Wherein, each optical fiber in input optical fibre array inserts this fixing light hole array and fixes accordingly in light hole, and output optical fibre array is positioned at the below of described controlled shadow shield, and its each optical fiber aligns with each optical fiber of input optical fibre array respectively; For each the movable light shield module unit in described controlled shadow shield, under the driving of driving circuit, the elastic beam of controlled shadow shield passes through electric current, electric current and described axial magnetic field effect produce Lorentz force, under Lorentz force effect, can there is deformation in elastic beam, thus corresponding movable light shield block is moved near equilibrium position, thus change the luminous flux being entered corresponding output optical fibre by input optical fibre via light hole corresponding on fixing shadow shield, movable light shield block.

2. array micro electro mechanical variable optical attenuator according to claim 1, is characterized in that, described controlled shadow shield is made on SOI wafer substrate for utilizing MEMS technology technology.

3. array micro electro mechanical variable optical attenuator according to claim 2, it is characterized in that, described movable light shield block is corresponding with the shape of described fixing light hole, and the size of described movable light shield block than the large several micron of the size of described fixing light hole to tens microns.

4. array micro electro mechanical variable optical attenuator according to claim 3, is characterized in that, described fixing light hole is square, circular or triangle.

5. array micro electro mechanical variable optical attenuator according to claim 2, is characterized in that, in described controlled shadow shield, is metal lead wire district in the surrounding of described movable light shield block array; It is the bonding region with fixing shadow shield bonding in the periphery of controlled shadow shield;

Described metal lead wire district comprises: control line, ground wire and anchor point, and wherein all ground wires realize in parallel with reticulate texture.

6. array micro electro mechanical variable optical attenuator according to claim 1, is characterized in that, described fixing shadow shield being fixed light hole is structure wide at the top and narrow at the bottom, and described input optical fibre is inserted by the wide mouth of this structure.

7. array micro electro mechanical variable optical attenuator according to claim 6, is characterized in that, it is integrated that described fixing shadow shield and controlled shadow shield pass through bonding pattern.

8. array micro electro mechanical variable optical attenuator according to claim 1, is characterized in that, described magnetic field generation device is annular permanent magnet, is positioned at the below of described controlled shadow shield.

9. array micro electro mechanical variable optical attenuator according to any one of claim 1 to 7, is characterized in that, described driving circuit is CMOS integrated circuit, and it utilizes bonding or pressure welding and described controlled shadow shield integrated.