3D MEMS small-matrix optical switch and preparation method thereof

Abstract

The invention discloses a 3D MEMS small-matrix optical switch and a preparation method thereof. The 3D MEMS small-matrix optical switch is composed of a packaging shell, optical switch chip assemblies on the input side and the output side, and collimators on the input side and the output side. The optical switch chip assemblies on the input side and the output side are respectively composed of MEMS optical switch bare core arrays on the input side and the output side, ceramic substrates on the input side and the output side, and control switching PCBs on the input side and the output side. Inner packaging of the optical switch chip assemblies is completed through the packaging shell, the free space cavity in the middle of the ship-shaped cavity of the packaging shell is used for full-crossing optical switching, and the optical switch chip assemblies on the input side and the output side adjust the angle of the rotating mirror on the MEMS optical switch bare chip array through power-on. Incident light is subjected to full-cross light exchange in a free space cavity, the size of the cavity is slightly larger than the range of a full-cross light path, a margin is reserved, light blocking is avoided, and the full-cross light source has the advantages of being small in insertion loss, high in integration level, small in size and free of welding.

Description

Technical Field

[0001] The present invention relates to the technical field of optical switches, and in particular to a 3D MEMS small matrix optical switch and a preparation method thereof. Background Art

[0002] An optical switch is a device that switches an optical signal from one optical channel to another. It is a core device for realizing functions such as optical cross-connection, optical add / drop multiplexing, network monitoring, and self-healing protection. There are various technologies for realizing optical switches. Among them, traditional optical switches that use electricity as the core to realize the on / off and connection of light are gradually unable to meet the needs of high-speed and large-capacity optical communications. All-optical switches that use light as the core to realize the on / off and connection of light do not have photoelectric conversion and have become a replacement for traditional optical switches and gradually occupied the market. MEMS (Micro Electro Mechanical System) optical switches, as an all-optical switch, are widely used because of their small size, low power consumption, and good scalability. MEMS optical switches use a rotating mirror array built on a semiconductor substrate to realize the deflection of the optical path. The rotating mirror inside the MEMS is usually a gold-plated silicon-based structure with a diameter of 1 mm, and the rotation angle is ±2 to 4.0°. The input collimator of the optical switch hits the light on the rotating mirror array, and the light is reflected to the corresponding output collimator of the optical switch through the rotation of the mirror of the rotating mirror array.

[0003] N×N MEMS optical switches can realize light input from any input channel IN1~INN and light output from any output channel OUT1~OUTN, and it is all-optical switching with fast switching time, which can realize large-capacity data transmission and exchange. At present, N×N MEMS optical switches are generally realized by cascading 2N ready-made 1×N MEMS optical switches and splicing fiber coils. Figure 1 The 8×8 MEMS optical switch formed by cascade splicing and coiling 16 MEMS optical switches is shown. The 1st to 8th paths of optical switch M1 are respectively fused with the 1st path from optical switch M9 to optical switch M16; the 1st to 8th paths of optical switch M2 are respectively fused with the 2nd path from optical switch M9 to optical switch M16; ...; the 1st to 8th paths of optical switch M8 are respectively fused with the 8th path from optical switch M9 to optical switch M16. The main disadvantages of this cascade splicing and coiling method are: 1) Large insertion loss: When cascade splicing two MEMS optical switches, the intermediate light needs to pass through more optical components, and the loss superposition is large. 2) Large volume: N×N pairs of optical fibers need to be coiled inside the module, and the space occupied by the MEMS device itself and the optical fiber coiling need to occupy a large space. 3) Long production time: N×N pairs of optical fibers need to be spliced, and the production time increases exponentially with the increase in the number of splicing points and coiling. Summary of the invention

[0004] The present invention aims to solve the problems of large insertion loss, large volume and long production time of the existing N×N MEMS optical switch based on cascade fusion fiber coil mode, and provides a 3D MEMS small matrix optical switch and a preparation method thereof.

[0005] To solve the above problems, the present invention is achieved through the following technical solutions:

[0006] A method for preparing a 3D MEMS small matrix optical switch comprises the following steps:

[0007] Step 1: Determine the type of MEMS optical switch bare die arrays selected for the input side and the output side according to the number of input channels and output channels of the MEMS optical switch to be designed;

[0008] Step 2: Determine the number of pin holes of the ceramic substrates on the input side and the output side according to the determined types of the MEMS optical switch bare core arrays on the input side and the output side; open a corresponding number of pin holes on the ceramic substrates on the input side and the output side according to the determined number of pin holes on the ceramic substrates on the input side and the output side, respectively, and the pin holes are arranged in a manner of reserving a space in the middle for placing the MEMS optical switch bare core array and surrounding the MEMS optical switch bare core array;

[0009] Step 3: embed a metal pin into each pin hole of the ceramic substrate on the input side and the output side, so that the upper end surface of the pin is flush with the front surface of the ceramic substrate, and the lower end surface of the pin is exposed to the back of the ceramic substrate, and the pin is fixed in the pin hole with glue;

[0010] Step 4: embed the pins exposed on the back of the ceramic substrates on the input side and the output side into the pads of the control transfer PCB boards on the input side and the output side respectively, and fix and electrically connect them by welding;

[0011] Step 5: fix all MEMS optical switch bare core arrays on the input side and the output side to the middle of the front side of the ceramic substrate on the input side and the output side by dispensing glue. At this time, all the pin holes of the ceramic substrate on the input side and the output side are surrounded by these MEMS optical switch bare core arrays;

[0012] Step 6, electrically connect each positive electrode Pad of all MEMS optical switch bare core arrays on the input side and the output side with the corresponding positive electrode Pin needle on the front side of the ceramic substrate on the input side and the output side by punching gold wire; electrically connect each GND Pad of all MEMS optical switch bare core arrays on the input side and the output side with the corresponding GND Pin needle on the front side of the ceramic substrate on the input side and the output side by punching gold wire; each positive electrode Pin needle on the front side of the ceramic substrate on the input side and the output side is electrically connected to the corresponding GND Pin needle by punching gold wire and through a Zener diode;

[0013] At this point, the optical switch chip components on the input side and the output side are obtained;

[0014] Step 7: According to the rotation angle of the rotating mirror of the MEMS optical switch bare die array, the optimal center distance D between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is determined by simulation and calculation with a certain margin in the X direction and the Y direction;

[0015] Step 8, preparing a packaging shell; the packaging shell consists of a boat-shaped cavity, an input side collimator fixing plate and an output side collimator fixing plate;

[0016] The boat-shaped cavity is a hollow and sealed boat-shaped cavity structure; the front and rear side walls of the boat-shaped cavity are symmetrically inclined at 45 degrees, and a chip embedding hole is opened thereon; the front and rear ends of the upper cover plate of the boat-shaped cavity are both provided with a collimating light-transmitting hole and a fixed mounting hole, wherein the collimating light-transmitting hole is located on the relatively outer side of the upper cover plate, and the fixed mounting hole is located on the relatively inner side of the upper cover plate; the vertical projection plane of the chip embedding hole coincides with the plane of the collimating light-transmitting hole; a light-transmitting sheet is embedded in the collimating light-transmitting hole;

[0017] The collimator fixing plates on the input side and the output side are both Z-shaped structures, the upper transverse parts of the collimator fixing plates on the input side and the output side are provided with collimator mounting holes, and the lower transverse parts of the collimator fixing plates on the input side and the output side are provided with fixing mounting holes;

[0018] The fixing holes of the lower transverse parts of the collimator fixing plates on the input side and the output side are respectively opposite to the fixing holes opened at both ends of the boat-shaped cavity, and the two are fixed by screws; the collimator mounting holes of the upper transverse parts of the collimator fixing plates on the input side and the output side are respectively opposite to the collimating light-transmitting holes opened at both ends of the boat-shaped cavity;

[0019] Step 9, symmetrically install the optical switch chip components on the input side and the output side on the front and rear side walls of the boat-shaped cavity, the ceramic substrate of the optical switch chip component is just embedded in the chip embedding hole, and the MEMS optical switch bare die array faces the inner side of the boat-shaped cavity; after the installation is completed, the center distance between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is D;

[0020] Step 10, respectively install the collimator arrays on the input side and the output side into the collimator installation holes on the upper transverse parts of the collimator fixing plates on the input side and the output side, and the light outlets of the collimators are opposite to the collimator light transmission holes of the boat-shaped cavity; after the installation is completed, the light outlets of the collimator array on the input side are aligned one by one with the rotating mirrors of the MEMS optical switch bare core array on the input side, and the light outlets of the collimator array on the output side are aligned one by one with the rotating mirrors of the MEMS optical switch bare core array on the output side;

[0021] Thus, a 3D MEMS small matrix optical switch is obtained.

[0022] In the above method, the center distance D between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is:

[0023]

[0024] In the formula, min means minimization, θ x and θ y They represent the rotation angles of the mirror of the MEMS optical switch bare die array in the X and Y directions, respectively. min and X max Respectively represent the preset minimum and maximum margins in the X direction, and Y min and Y max Respectively represent the preset minimum and maximum margins in the Y direction, d x The X-direction spacing between two adjacent mirrors of the MEMS optical switch bare die array is d y It represents the Y-direction spacing between two adjacent rotating mirrors of the MEMS optical switch bare die array, i.e., the row spacing, L represents the total number of rows of the MEMS optical switch bare die array, and A represents the total number of columns of the MEMS optical switch bare die array.

[0025] The 3D MEMS small matrix optical switch prepared by the above method includes a packaging shell, optical switch chip components on the input side and the output side, and collimators on the input side and the output side. The packaging shell consists of a boat-shaped cavity, a collimator fixing plate on the input side, and a collimator fixing plate on the output side. The boat-shaped cavity is a hollow and sealed boat-shaped cavity structure. The front and rear side walls of the boat-shaped cavity are symmetrically inclined at 45°, and a chip embedding hole is provided thereon. Collimating light-transmitting holes and fixed mounting holes are provided at both the front and rear ends of the upper cover plate of the boat-shaped cavity, wherein the collimating light-transmitting hole is located on the relatively outer side of the upper cover plate, and the fixed mounting hole is located on the relatively inner side of the upper cover plate. The vertical projection plane of the chip embedding hole coincides with the plane of the collimating light-transmitting hole. A light-transmitting sheet is embedded in the collimating light-transmitting hole. The collimator fixing plates on the input side and the output side are both Z-shaped structures, and the upper transverse parts of the collimator fixing plates on the input side and the output side are provided with collimator mounting holes, and the lower transverse parts of the collimator fixing plates on the input side and the output side are provided with fixed mounting holes. The fixed mounting holes of the lower transverse parts of the collimator fixing plates on the input side and the output side are respectively opposite to the fixed mounting holes opened at both ends of the boat-shaped cavity, and the two are fixed by screws. The collimator mounting holes of the upper transverse parts of the collimator fixing plates on the input side and the output side are respectively opposite to the collimation light-transmitting holes opened at both ends of the boat-shaped cavity. The optical switch chip components on the input side and the output side are respectively composed of MEMS optical switch bare core arrays on the input side and the output side, ceramic substrates on the input side and the output side, and control transfer PCB boards on the input side and the output side. The MEMS optical switch bare core array is placed on the front of the ceramic substrate, and the control transfer PCB board is placed on the back of the ceramic substrate. The MEMS optical switch bare core array and the control transfer PCB board are fixed and electrically connected based on the pins on the ceramic substrate. The optical switch chip components on the input side and the output side are symmetrically installed on the front and rear side walls of the boat-shaped cavity, and the ceramic substrate of the optical switch chip components is just embedded in the chip embedding hole, and the MEMS optical switch bare core array faces the inner side of the boat-shaped cavity. After the installation is completed, the center distance between the MEMS optical switch bare core array on the input side and the MEMS optical switch bare core array on the output side is D. The collimator arrays on the input side and the output side are respectively installed in the collimator mounting holes of the upper transverse part of the collimator fixing plates on the input side and the output side, and the light outlet of the collimator is opposite to the collimator light transmission hole of the boat-shaped cavity. After the installation is completed, the light outlet of the collimator array on the input side is directly opposite to the rotating mirror of the MEMS optical switch bare core array on the input side, and the light outlet of the collimator array on the output side is directly opposite to the rotating mirror of the MEMS optical switch bare core array on the output side.

[0026] In the above optical switch, the center distance D between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is:

[0027]

[0028] In the formula, min means minimization, θ x and θ y They represent the rotation angles of the mirror of the MEMS optical switch bare die array in the X and Y directions, respectively. min and X max Respectively represent the preset minimum and maximum margins in the X direction, and Y min and Y max Respectively represent the preset minimum and maximum margins in the Y direction, d x The X-direction spacing between two adjacent mirrors of the MEMS optical switch bare die array is d y It represents the Y-direction spacing between two adjacent rotating mirrors of the MEMS optical switch bare die array, i.e., the row spacing, L represents the total number of rows of the MEMS optical switch bare die array, and A represents the total number of columns of the MEMS optical switch bare die array.

[0029] Compared with the prior art, the present invention has the following characteristics:

[0030] 1. Each channel is less affected by phase difference and has low insertion loss.

[0031] 2. The optical chip and electrical circuit connection are highly integrated, and the optical switch module is small in size.

[0032] 3. No welding is required, and the production hours are significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figure is a schematic diagram of an 8×8 MEMS optical switch formed by cascading and splicing 16 1×8 MEMS optical switches.

[0034] Figure 2 Schematic diagram of a 2×4 MEMS optical switch bare die array.

[0035] Figure 3 Schematic diagram of a ceramic substrate, (a) top view, (b) side view, and (c) stereoscopic view.

[0036] Figure 4 Schematic diagram of the control transfer PCB board, (a) side view, (b) top view, (c) bottom view.

[0037] Figure 5 Schematic diagram of gold wire punching for MEMS optical switch array.

[0038] Figure 6 This is a schematic diagram for calculating the optimal center distance between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side.

[0039] Figure 7 Schematic diagram of the boat-shaped cavity, (a) stereoscopic view, (b) side sectional view, (c) top view.

[0040] Figure 8 This is the collimator fixing plate on the input side; (a) top view, (b) side view, (c) stereoscopic view.

[0041] Fig. 9 The collimator fixing plate on the output side; (a) top view, (b) side view, (c) stereoscopic view.

[0042] Fig.10 Schematic diagram of a 3D MEMS small matrix optical switch; (a) side view, (b) top view, (c) stereo view.

[0043] Numbers in the figure: 1-1, boat-shaped cavity, 1-2, collimator fixing plate on the input side, 1-3, collimator fixing plate on the output side, 2, optical switch chip assembly on the input side, 3, optical switch chip assembly on the output side, 4, collimator on the input side, 5, collimator on the output side. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below by taking an 8×8 MEMS optical switch as an example.

[0045] A method for preparing a 3D MEMS small matrix optical switch comprises the following steps:

[0046] Step 1: Determine the type of MEMS optical switch bare die arrays selected for the input side and the output side according to the number of input channels and output channels of the MEMS optical switch to be designed.

[0047] This embodiment uses a MEMS optical switch bare core array of model TF31, which is composed of 8 MEMS optical switch bare cores arranged closely in a 2×4 matrix. The middle of each MEMS optical switch bare core is a mirror, and the four sides surrounding the mirror are pads. The distance between the centers of two MEMS optical switch bare cores adjacent to each other horizontally is 3.24mm, and the distance between the centers of two MEMS optical switch bare cores adjacent to each other vertically is 1.9mm. Figure 2 shown.

[0048] Step 2: Determine the number of pin holes of the ceramic substrate on the input side and the output side according to the determined type of the MEMS optical switch bare core array on the input side and the output side; open a corresponding number of pin holes on the ceramic substrate on the input side and the output side according to the determined number of pin holes of the ceramic substrate on the input side and the output side, respectively, and these pin holes are arranged in a manner of reserving a space in the middle for placing the MEMS optical switch bare core array and surrounding the MEMS optical switch bare core array.

[0049] Considering the advantages of ceramics such as good temperature performance, insulation, and easy processing, the present invention uses a ceramic substrate to carry the MEMS optical switch bare die array. Figure 3 As shown in the figure, the diameter of the Pin hole is Φ0.5mm.

[0050] Step 3: Insert a metal pin into each pin hole of the ceramic substrate on the input side and the output side, and make the upper end surface of the pin flush with the front surface of the ceramic substrate (flatness δ0 +0.4mm ), the lower end surface of the Pin needle is exposed from the back side of the ceramic substrate, and the Pin needle is fixed in the Pin needle hole by glue.

[0051] The function of the pin is to lead the pad on the bare core of the MEMS optical switch on the front side of the ceramic substrate to the back side of the ceramic substrate. In this embodiment, the pin is a Φ0.45 mm gold-plated cylinder.

[0052] Step 4: embed the pins exposed on the back of the ceramic substrates on the input side and the output side into the pads of the control transfer PCB boards on the input side and the output side respectively, and fix and electrically connect them by welding.

[0053] Control transfer PCB board such as Figure 4 As shown, 50 pads are connected to an external driver circuit board through a 16P FFC / FPC electrical connector.

[0054] Step 5: Fix all MEMS optical switch bare core arrays on the input side and the output side to the middle of the front side of the ceramic substrate on the input side and the output side by dispensing glue. At this time, all the pin holes of the ceramic substrate on the input side and the output side are surrounded by these MEMS optical switch bare core arrays.

[0055] Step 6: Electrically connect each positive electrode pad of all MEMS optical switch bare core arrays on the input side and the output side to the corresponding positive electrode pin on the front of the ceramic substrate on the input side and the output side by punching gold wire. Electrically connect each GND pad of all MEMS optical switch bare core arrays on the input side and the output side to the corresponding GND pin on the front of the ceramic substrate on the input side and the output side by punching gold wire. Each positive electrode pin on the front of the ceramic substrate on the input side and the output side is electrically connected to the corresponding GND pin by punching gold wire and through a Zener diode.

[0056] At this point, the optical switch chip assembly 2 / 3 on the input side and the output side is obtained.

[0057] The pads of the TF31 MEMS optical switch bare core array include GND, X+, Y+, X-, and Y-, which need to be gold-plated to the outside to connect with the driver. The GND Pad can be connected in series, while the X+Pad, Y+Pad, X-Pad, and Y-Pad need to be wired separately. Figure 5 The diagram is a schematic diagram of the gold wire punching of the MEMS optical switch array. The dark circles outside the MEMS optical switch array are the positive electrode pins, and the dark lines are the corresponding positive electrode gold wire connection lines. The light circles outside the MEMS optical switch array are the GND pins, and the light lines are the corresponding GDN gold wire connection lines. The small squares inside the dark circles outside the MEMS optical switch array are Zener diodes, which are used to provide ESD protection and surge protection for the MEMS optical switch bare die array.

[0058] Step 7: According to the rotation angle of the rotating mirror of the MEMS optical switch bare die array, the optimal center distance D between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is obtained by simulation and calculation with a certain margin in the X direction and the Y direction based on the following formula:

[0059]

[0060] In the formula, min means minimization, θ x and θ y They represent the rotation angles of the mirror of the MEMS optical switch bare die array in the X and Y directions, respectively. min and X max Respectively represent the preset minimum and maximum margins in the X direction, and Y min and Y max Respectively represent the preset minimum and maximum margins in the Y direction, d x The X-direction spacing between two adjacent mirrors of the MEMS optical switch bare die array is d y It represents the Y-direction spacing between two adjacent rotating mirrors of the MEMS optical switch bare die array, i.e., the row spacing, A represents the total number of rows of the MEMS optical switch bare die array, and L represents the total number of columns of the MEMS optical switch bare die array.

[0061] Figure 6 The schematic diagram of the optimal center distance calculation of the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side. In the figure, the left side represents the MEMS optical switch bare die array on the input side, and the right side represents the MEMS optical switch bare die array on the output side, and the two are arranged at 45 degrees to each other. The top view is the Y-axis rotation direction of the optical chip. The front view is the X-axis rotation direction of the optical chip.

[0062] Depend on Figure 6From the top view, we can see that the normal and the light are in the same plane before and after the Y-axis movement. Therefore, the calculation formulas for the Y-axis normal rotation angle γ and the light rotation angle θ are: When the Y-axis rotation angle of the rotating mirror of the MEMS optical switch bare die array of model TF31 is ≥2° and the optimal center distance D is 70mm, the maximum Y-axis optical path rotation angle is 1.87°. The Y-direction normal rotation angle γ is calculated to be 1.87° / 2=0.935°, and the Y-direction margin is obtained to be (2°-0.935°) / 2°=53.25%.

[0063] Depend on Figure 6 It can be seen from the front view that the normal and the light are not in the same plane before and after the X-axis movement, so the calculation formula for the Y-axis normal rotation angle γ and the light rotation angle θ is: When the X-axis rotation angle of the rotating mirror of the MEMS optical switch bare core of model TF31 is ≥4° and the optimal center distance D is 70mm, the maximum Y-axis optical path rotation angle is 4.8221°. Calculate the X-axis normal rotation angle Therefore, the X-direction margin is (4°-3.409°) / 4°=14.78%.

[0064] Since the above calculated margins of the rotating mirror of the MEMS optical switch bare core array in the X and Y directions are 14.78% and 53.25% respectively, which meet the preset margins in the X and Y directions, the optimal center distance D between the MEMS optical switch bare core array on the input side and the MEMS optical switch bare core array on the output side is set to 70 mm in this embodiment.

[0065] Step 8: Prepare a packaging shell. The packaging shell consists of a boat-shaped cavity 1-1, an input-side collimator fixing plate 1-2, and an output-side collimator fixing plate 1-3.

[0066] The boat-shaped cavity 1-1 is a hollow and sealed boat-shaped cavity structure. The front and rear side walls of the boat-shaped cavity 1-1 are symmetrically inclined at 45 degrees, and a chip embedding hole is provided thereon. The front and rear ends of the upper cover plate of the boat-shaped cavity 1-1 are provided with collimating light-transmitting holes and fixed mounting holes, wherein the collimating light-transmitting holes are located on the relatively outer side of the upper cover plate, and the fixed mounting holes are located on the relatively inner side of the upper cover plate. The vertical projection plane of the chip embedding hole coincides with the plane of the collimating light-transmitting hole. A light-transmitting sheet is embedded in the collimating light-transmitting hole. In this embodiment, the light-transmitting sheet is a flat window coated glass sheet. Figure 7 The schematic diagram of the boat-shaped cavity 1-1 is made of a whole piece of stainless steel, and the outer wall thickness of the cavity is as thick as possible, with a wall thickness of 3.0 to 3.6 mm, respectively, to ensure the stability of the packaging structure. The length, width and height are 83.3×14×13.5 mm, so that it can be installed on a semi-U plug-in tray to improve the versatility of the product.

[0067] The collimator fixing plates 1-2 / 1-3 on the input side and the output side are both Z-shaped structures, and collimator mounting holes are opened on the upper transverse parts of the collimator fixing plates 1-2 / 1-3 on the input side and the output side, and fixing mounting holes are opened on the lower transverse parts of the collimator fixing plates 1-2 / 1-3 on the input side and the output side. Figure 8 is the collimator fixing plate on the input side, Fig. 9 It is the collimator fixing plate on the output side. Since there are two windows for input and output light paths on the boat-shaped cavity 1-1, and a flat window coated glass sheet with a 5° angle is sealed on the window, this 5° angle makes the collimator have a certain incident angle. By querying the refractive index of each medium and simulating the calculation, it is found that the angle of the collimator is 2.56°. Therefore, the collimator fixing structure is designed to fix the collimator at 2.56°. The hole for fixing the collimator is a Φ1.6×3mm circular hole. The collimator fixing plate 1-2 on the input side and the collimator fixing plate 1-3 on the output side can be asymmetrical or symmetrical.

[0068] The fixing holes of the lower transverse part of the collimator fixing plate 1-2 / 1-3 on the input side and the output side are respectively opposite to the fixing holes opened at both ends of the boat-shaped cavity 1-1, and the two are fixed by screws. In this embodiment, the collimator fixing plate is installed on the boat-shaped cavity 1-1 using screws and 353ND glue. The collimator mounting holes of the upper transverse part of the collimator fixing plate 1-2 / 1-3 on the input side and the output side are respectively opposite to the collimating light-transmitting holes opened at both ends of the boat-shaped cavity 1-1.

[0069] The present invention utilizes a packaging shell to complete the internal packaging of the optical switch chip assembly 2 / 3 on the input side and the output side. The free space cavity in the middle of the boat-shaped cavity 1-1 of the packaging shell is used for full cross optical exchange. The optical switch chip assembly 2 / 3 on the input side and the output side adjusts the angle of the rotating mirror on the MEMS optical switch bare core array by powering on, so that the incident light performs full cross optical exchange in the free space cavity. The cavity size is slightly larger than the range of the full cross optical path, leaving a margin to avoid light blocking.

[0070] Step 9, symmetrically install the optical switch chip assembly 2 / 3 on the front and rear side walls of the boat-shaped cavity 1-1, the ceramic substrate of the optical switch chip assembly is just embedded in the chip embedding hole, and the MEMS optical switch bare die array faces the inner side of the boat-shaped cavity 1-1; after the installation is completed, the center distance between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is D;

[0071] Step 10, respectively install the collimator 4 / 5 arrays on the input side and the output side into the collimator installation holes of the upper transverse parts of the collimator fixing plates 1-2 / 1-3 on the input side and the output side, and the light outlets of the collimators are opposite to the collimator light-transmitting holes of the boat-shaped cavity 1-1; after the installation is completed, the light outlets of the collimator 4 array on the input side are aligned one by one with the rotating mirrors of the MEMS optical switch bare core array on the input side, and the light outlets of the collimator 5 array on the output side are aligned one by one with the rotating mirrors of the MEMS optical switch bare core array on the output side;

[0072] At this point, a 3D MEMS small matrix optical switch is obtained.

[0073] It is known that the center spacing of the 2×4 MEMS optical switch bare core array is 70mm, and the collimator optical path L0 = 72.29 + 8.5 + 8.5 = 89.29mm, which is an integer of 90mm. The diameter of the rotating mirror of the MEMS optical switch bare core array model TF31 is 1.0mm. Since the 2×4 MEMS optical switch bare core array is arranged at a 45° angle, the rotating mirror is projected on the vertical plane of the incident light or the outgoing light, which is an ellipse with a length of 1.0mm and a width of 0.707mm. In order to make the collimator's spot fall completely on the rotating mirror, the collimator's spot needs to be optimized. Since the collimator working distance and spot size are a pair of contradictory parameters: the larger the C-Lens curvature R, the larger the working distance (the smaller the insertion loss), but the larger the spot. The smaller the C-Lens curvature R, the smaller the spot, but the smaller the working distance (the larger the insertion loss). By calculating and designing the curvature and length of the C-Lens, the optimal curvature and the optimal spot size are selected.

[0074] The 3D MEMS small matrix optical switch prepared by the above method, such as Fig.10 As shown, it includes a packaging shell, optical switch chip components 2 / 3 on the input side and the output side, and collimators 4 / 5 on the input side and the output side.

[0075] The packaging shell is composed of a boat-shaped cavity 1-1, an input side collimator fixing plate 1-2 and an output side collimator fixing plate 1-3. The boat-shaped cavity 1-1 is a hollow sealed boat-shaped cavity structure. The front and rear side walls of the boat-shaped cavity 1-1 are symmetrically inclined at 45°, and a chip embedding hole is provided thereon. Collimating light-transmitting holes and fixed mounting holes are provided at the front and rear ends of the upper cover plate of the boat-shaped cavity 1-1, wherein the collimating light-transmitting holes are located on the relatively outer side of the upper cover plate, and the fixed mounting holes are located on the relatively inner side of the upper cover plate. The vertical projection plane of the chip embedding hole coincides with the plane of the collimating light-transmitting hole. A light-transmitting sheet is embedded in the collimating light-transmitting hole. The collimator fixing plates 1-2 / 1-3 on the input side and the output side are both Z-shaped structures, and collimator mounting holes are provided on the upper transverse parts of the collimator fixing plates 1-2 / 1-3 on the input side and the output side, and fixed mounting holes are provided on the lower transverse parts of the collimator fixing plates 1-2 / 1-3 on the input side and the output side. The fixed mounting holes of the lower transverse parts of the collimator fixing plates 1-2 / 1-3 on the input side and the output side are respectively opposite to the fixed mounting holes provided at both ends of the boat-shaped cavity 1-1, and the two are fixed by screws. The collimator mounting holes of the upper transverse parts of the collimator fixing plates 1-2 / 1-3 on the input side and the output side are respectively opposite to the collimation light-transmitting holes provided at both ends of the boat-shaped cavity 1-1.

[0076] The optical switch chip components 2 / 3 on the input side and the output side are respectively composed of MEMS optical switch bare core arrays on the input side and the output side, ceramic substrates on the input side and the output side, and control transfer PCB boards on the input side and the output side. The MEMS optical switch bare core array is placed on the front of the ceramic substrate, and the control transfer PCB board is placed on the back of the ceramic substrate. The MEMS optical switch bare core array and the control transfer PCB board are fixed and electrically connected based on the pins on the ceramic substrate. The optical switch chip components 2 / 3 on the input side and the output side are symmetrically installed on the front and rear side walls of the boat-shaped cavity 1-1, and the ceramic substrate of the optical switch chip component is just embedded in the chip embedding hole, and the MEMS optical switch bare core array faces the inner side of the boat-shaped cavity 1-1; after the installation is completed, the center distance between the MEMS optical switch bare core array on the input side and the MEMS optical switch bare core array on the output side is D. The collimator 4 / 5 arrays on the input side and the output side are respectively installed in the collimator installation holes of the upper horizontal parts of the collimator fixing plates 1-2 / 1-3 on the input side and the output side, and the light outlets of the collimators are opposite to the collimator light-transmitting holes of the boat-shaped cavity 1-1; after the installation is completed, the light outlets of the collimator 4 array on the input side are opposite to the rotating mirrors of the MEMS optical switch bare core array on the input side, and the light outlets of the collimator 5 array on the output side are opposite to the rotating mirrors of the MEMS optical switch bare core array on the output side.

[0077] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention, and therefore the present invention is not limited to the above specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. A method for preparing a 3D MEMS small matrix optical switch, characterized in that: The steps include: Step 1: Determine the type of MEMS optical switch bare die arrays selected for the input side and the output side according to the number of input channels and output channels of the MEMS optical switch to be designed; Step 2: Determine the number of pin holes of the ceramic substrates on the input side and the output side according to the determined types of the MEMS optical switch bare core arrays on the input side and the output side; open a corresponding number of pin holes on the ceramic substrates on the input side and the output side according to the determined number of pin holes on the ceramic substrates on the input side and the output side, respectively, and the pin holes are arranged in a manner of reserving a space in the middle for placing the MEMS optical switch bare core array and surrounding the MEMS optical switch bare core array; Step 3: embed a metal pin into each pin hole of the ceramic substrate on the input side and the output side, so that the upper end surface of the pin is flush with the front surface of the ceramic substrate, and the lower end surface of the pin is exposed to the back of the ceramic substrate, and the pin is fixed in the pin hole with glue; Step 4: embed the pins exposed on the back of the ceramic substrates on the input side and the output side into the pads of the control transfer PCB boards on the input side and the output side respectively, and fix and electrically connect them by welding; Step 5: fix all MEMS optical switch bare core arrays on the input side and the output side to the middle of the front side of the ceramic substrate on the input side and the output side by dispensing glue. At this time, all the pin holes of the ceramic substrate on the input side and the output side are surrounded by these MEMS optical switch bare core arrays; Step 6, electrically connect each positive electrode Pad of all MEMS optical switch bare core arrays on the input side and the output side with the corresponding positive electrode Pin needle on the front side of the ceramic substrate on the input side and the output side by punching gold wire; electrically connect each GND Pad of all MEMS optical switch bare core arrays on the input side and the output side with the corresponding GND Pin needle on the front side of the ceramic substrate on the input side and the output side by punching gold wire; each positive electrode Pin needle on the front side of the ceramic substrate on the input side and the output side is electrically connected to the corresponding GND Pin needle by punching gold wire and through a Zener diode; At this point, the optical switch chip components (2) and (3) on the input side and the output side are obtained; Step 7: According to the rotation angle of the rotating mirror of the MEMS optical switch bare die array, the optimal center distance D between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is determined by simulation and calculation with a certain margin in the X direction and the Y direction; Step 8, preparing a packaging shell; the packaging shell consists of a boat-shaped cavity (1-1), an input side collimator fixing plate (1-2) and an output side collimator fixing plate (1-3); The boat-shaped cavity (1-1) is a hollow and sealed boat-shaped cavity structure; the front and rear side walls of the boat-shaped cavity (1-1) are symmetrically arranged at an angle of 45 degrees, and a chip embedding hole is provided thereon; the front and rear ends of the upper cover plate of the boat-shaped cavity (1-1) are provided with a collimating light-transmitting hole and a fixing installation hole, wherein the collimating light-transmitting hole is located on the relatively outer side of the upper cover plate, and the fixing installation hole is located on the relatively inner side of the upper cover plate; the vertical projection plane of the chip embedding hole coincides with the plane of the collimating light-transmitting hole; and a light-transmitting sheet is embedded in the collimating light-transmitting hole; The collimator fixing plates (1-2) (1-3) on the input side and the output side are both Z-shaped structures, the upper transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side are provided with collimator mounting holes, and the lower transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side are provided with fixing mounting holes; The fixing installation holes of the lower transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side are respectively opposite to the fixing installation holes opened at the two ends of the boat-shaped cavity (1-1), and the two are fixed by screws; the collimator installation holes of the upper transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side are respectively opposite to the collimating light-transmitting holes opened at the two ends of the boat-shaped cavity (1-1); Step 9, symmetrically install the optical switch chip components (2) (3) on the input side and the output side on the front and rear side walls of the boat-shaped cavity (1-1), with the ceramic substrate of the optical switch chip component just embedded in the chip embedding hole, and the MEMS optical switch bare core array facing the inner side of the boat-shaped cavity (1-1); after the installation is completed, the center distance between the MEMS optical switch bare core array on the input side and the MEMS optical switch bare core array on the output side is D; Step 10, respectively install the collimator (4) (5) arrays on the input side and the output side into the collimator installation holes on the upper transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side, and the light outlets of the collimators are opposite to the collimator light transmission holes of the boat-shaped cavity (1-1); after the installation is completed, the light outlets of the collimator (4) array on the input side are aligned with the rotating mirrors of the MEMS optical switch bare core array on the input side, and the light outlets of the collimator (5) array on the output side are aligned with the rotating mirrors of the MEMS optical switch bare core array on the output side; Thus, a 3D MEMS small matrix optical switch is obtained.

2. The method for preparing a 3D MEMS small matrix optical switch according to claim 1, characterized in that: The center distance D between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is: In the formula, min means minimization, θ x and θ y They represent the rotation angles of the mirror of the MEMS optical switch bare die array in the X and Y directions, respectively. min and X max Respectively represent the preset minimum and maximum margins in the X direction, and Y min and Y max Respectively represent the preset minimum and maximum margins in the Y direction, d x The X-direction spacing between two adjacent mirrors of the MEMS optical switch bare die array is d y It represents the Y-direction spacing between two adjacent rotating mirrors of the MEMS optical switch bare die array, i.e., the row spacing, L represents the total number of rows of the MEMS optical switch bare die array, and A represents the total number of columns of the MEMS optical switch bare die array.

3. A 3D MEMS small matrix optical switch prepared by the method of claim 1, characterized in that: It comprises a packaging shell, optical switch chip components (2) (3) on the input side and the output side, and collimators (4) (5) on the input side and the output side; The packaging shell is composed of a boat-shaped cavity (1-1), an input-side collimator fixing plate (1-2) and an output-side collimator fixing plate (1-3); The boat-shaped cavity (1-1) is a hollow and sealed boat-shaped cavity structure; the front and rear side walls of the boat-shaped cavity (1-1) are symmetrically arranged at an angle of 45 degrees, and a chip embedding hole is provided thereon; the front and rear ends of the upper cover plate of the boat-shaped cavity (1-1) are provided with a collimating light-transmitting hole and a fixing installation hole, wherein the collimating light-transmitting hole is located on the relatively outer side of the upper cover plate, and the fixing installation hole is located on the relatively inner side of the upper cover plate; the vertical projection plane of the chip embedding hole coincides with the plane of the collimating light-transmitting hole; and a light-transmitting sheet is embedded in the collimating light-transmitting hole; The collimator fixing plates (1-2) (1-3) on the input side and the output side are both Z-shaped structures, the upper transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side are provided with collimator mounting holes, and the lower transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side are provided with fixing mounting holes; The fixing installation holes of the lower transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side are respectively opposite to the fixing installation holes opened at the two ends of the boat-shaped cavity (1-1), and the two are fixed by screws; the collimator installation holes of the upper transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side are respectively opposite to the collimating light-transmitting holes opened at the two ends of the boat-shaped cavity (1-1); The optical switch chip components (2) and (3) on the input side and the output side are respectively composed of MEMS optical switch bare core arrays on the input side and the output side, ceramic substrates on the input side and the output side, and control transfer PCB boards on the input side and the output side; the MEMS optical switch bare core array is placed on the front side of the ceramic substrate, and the control transfer PCB board is placed on the back side of the ceramic substrate; the MEMS optical switch bare core array and the control transfer PCB board are fixed and electrically connected based on the pins on the ceramic substrate; The optical switch chip components (2) (3) on the input side and the output side are symmetrically mounted on the front and rear side walls of the boat-shaped cavity (1-1), the ceramic substrate of the optical switch chip component is just embedded in the chip embedding hole, and the MEMS optical switch bare core array faces the inner side of the boat-shaped cavity (1-1); after the installation is completed, the center distance between the MEMS optical switch bare core array on the input side and the MEMS optical switch bare core array on the output side is D; The collimator (4) (5) arrays on the input side and the output side are respectively installed in the collimator installation holes on the upper transverse parts of the collimator fixing plates (1-2) (1-3) on the input side and the output side, and the light outlets of the collimators are opposite to the collimator light transmission holes of the boat-shaped cavity (1-1); after the installation is completed, the light outlets of the collimator (4) array on the input side are aligned with the rotating mirrors of the MEMS optical switch bare core array on the input side, and the light outlets of the collimator (5) array on the output side are aligned with the rotating mirrors of the MEMS optical switch bare core array on the output side.

4. A 3D MEMS small matrix optical switch according to claim 3, characterized in that: The center distance D between the MEMS optical switch bare die array on the input side and the MEMS optical switch bare die array on the output side is: In the formula, min means minimization, θ x and θ y They represent the rotation angles of the mirror of the MEMS optical switch bare die array in the X and Y directions, respectively. min and X max Respectively represent the preset minimum and maximum margins in the X direction, and Y min and Y max Respectively represent the preset minimum and maximum margins in the Y direction, d x The X-direction spacing between two adjacent mirrors of the MEMS optical switch bare die array is d y It represents the Y-direction spacing between two adjacent rotating mirrors of the MEMS optical switch bare die array, i.e., the row spacing, L represents the total number of rows of the MEMS optical switch bare die array, and A represents the total number of columns of the MEMS optical switch bare die array.

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