Microlens array, planar optical fiber array and coupling method

Abstract

The invention discloses a micro-lens array which comprises a micro-lens array body, the micro-lens array body is provided with a lens substrate, the lens substrate is provided with a plurality of detection areas, a gap is formed between every two adjacent detection areas, the invention further discloses a surface optical fiber array, and the surface optical fiber array is provided with a positioning substrate. The invention further discloses a coupling method of the micro-lens array and the surface optical fiber array, an infrared light source is used, a one-to-four beam splitter is connected, four interfaces of the beam splitter are connected with four corners of the optical fiber array, the infrared light source is used, and the optical fiber receiving end surface is matched with a light beam emitted by a lens. And connecting the collimator, determining whether the light spot of the collimator covers the light-transmitting area of the lens array, and connecting the light source with the collimator. The invention provides a micro-lens array, a surface optical fiber array and a coupling method, which can increase the coupling efficiency of an optical fiber array and a lens array, reduce the coupling loss and improve the signal transmission efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a microlens array, a surface optical fiber array and a coupling method. Background Art

[0002] With the rapid development of optical communication technology and the widespread application of intensive technology, devices used for optical signal transmission and processing are gradually developing towards high integration and arraying.

[0003] Microlens array fiber array coupling technology is an efficient fiber coupling method, mainly for the mechanism, modeling, design and experimental verification of multifunctional, reconfigurable optical diffraction neural networks. The precise coupling of optical signals through microlens arrays can achieve efficient capture and transmission of sensor signals, and can be used to realize processing functions such as shaping and filtering of optical signals.

[0004] In order to increase the channel capacity and the integration of devices, a combination of lens array and fiber array is required. In particular, the number of units in the fiber array and lens array is large, and the traditional design coupling method of a single fiber and a single lens is no longer used. A design and coupling method that can ensure controllable optical tolerance, high coupling efficiency, low loss, and flexible application needs to be developed. Summary of the invention

[0005] The object of the present invention is to provide a microlens array, a surface optical fiber array and a coupling method to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a microlens array, characterized in that it comprises:

[0007] The microlens array comprises a lens substrate, a plurality of detection areas are arranged on the lens substrate, and a spacing gap is arranged between two adjacent detection areas.

[0008] In a further embodiment, the lens substrate has a size of 5 mm×5 mm, and a detection area of ​​900 μm×900 μm;

[0009] There are 25 detection areas, and the 25 detection areas are located at the center of the lens substrate. The area of ​​each detection area is about 100um×100um. The center points of adjacent detection areas are spaced 200um apart and are arranged in a 5×5 manner.

[0010] In a further embodiment, the lens is made of grade 0 fused quartz, the effective light-transmitting area is only the microlens, and other areas except the lens are not light-transmitting.

[0011] A surface optical fiber array, applied to the microlens array, comprises:

[0012] A surface optical fiber array, wherein the surface optical fiber array has a positioning substrate, the optical fibers of the surface optical fiber array are arranged in a 5×5 structure on the positioning substrate, and the optical fiber receiving end face matches the light beam emitted by the lens;

[0013] The diameter of the lens output light spot is smaller than the core diameter of the optical fiber.

[0014] In a further embodiment, the positioning substrate is made of single crystal silicon.

[0015] In a further embodiment, the center interval between two adjacent optical fibers is 200um±1um.

[0016] In a further embodiment, the optical fiber of the surface optical fiber array is a multimode optical fiber with a core diameter of 50 um, and the optical fiber pigtail interface is a fiber optic connector.

[0017] The coupling method of the microlens array and the surface optical fiber array adopts the surface optical fiber array, and the coupling steps are as follows:

[0018] a) Use an infrared light source to connect a one-to-four beam splitter, connect the four interfaces of the beam splitter to the four corners of the fiber array (1, 5, 21, 25), and roughly align the four corners of the lens with the four corners of the fiber array. Observe the rough alignment effect from one side of the lens array.

[0019] b) Use an infrared light source, connect a collimator, and confirm whether the light spot of the collimator covers the light transmission area of ​​the lens array;

[0020] c) Connect the light source to the collimator, connect the pigtails at the four corners of the fiber array to the optical power meter, close the lens array to the fiber array, finely adjust the position of the collimator and the fiber array, and average the optical power at the four corners;

[0021] d) Pull apart the optical fiber array and adjust the position of the optical fiber array and the lens array to a distance of 500um;

[0022] e) Then make fine adjustments to the fiber array in different directions and start fine-tuning until the output optical power is maximum;

[0023] Level the optical power at the four corners;

[0024] f) Record the optical power of the 25-channel optical fiber array at this time; move the position of the optical fiber array, and record the 25-channel optical power meter readings after axial and angular movement of different distances, and obtain the assembly tolerance as a subsequent reference.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention adopts the design and coupling mode of 5×5 optical fiber array and microlens. The microlens array is a structure composed of multiple micron-sized lenses arranged in a certain pattern. These microlenses can achieve precise control and focusing of optical signals by precisely controlling their shapes and positions. After coupling with the surface optical fiber array, fine regulation of optical signals can be achieved, and the coupling efficiency of optical signals between different optical fibers can be significantly improved. The coupling combination of the microlens array and the surface optical fiber array can improve the integration and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the lens substrate of the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of parallel light entering the microlens array of the present invention;

[0029] Figure 3 It is a schematic diagram of the optical fiber arrangement structure of the planar array of the present invention;

[0030] Figure 4 This is a block diagram of the coupling principle between the microlens array and the planar optical fiber array of the present invention. DETAILED DESCRIPTION

[0031] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Embodiment, a microlens array, such as Figure 1 As shown, it includes: a microlens array, the microlens array has a lens substrate, a plurality of detection areas are arranged on the lens substrate, and a spacing gap is arranged between two adjacent detection areas.

[0033] Specifically, the size of the lens substrate is 5mm×5mm, and the detection area is 900μm×900μm; there are 25 detection areas, and the 25 detection areas are located at the center of the lens substrate. The area of ​​each detection area is about 100um×100um, and the center points of adjacent detection areas are spaced 200um apart, and are arranged in a 5×5 manner. In order to improve the coupling efficiency, the light spot of the lens is consistent with the core diameter of the optical fiber. Considering the matching degree between the core diameter and the light spot, according to the arrangement of the microlens array, the array optical fiber is also designed to be arranged in a 5×5 arrangement. The material of the positioning substrate is single crystal silicon, and the center interval between the optical fibers is 200um. The light spot size is designed according to the lens size of 100um. In order to ensure the coupling efficiency of the system, the light beam emitted by the lens is matched with the receiving end face of the optical fiber as much as possible, that is, the diameter of the light spot emitted by the lens is as small as possible from the core diameter of the optical fiber.

[0034] It should be noted that the lens is made of grade 0 fused quartz, and the only effective light-transmitting area is the microlens, and other areas except the lens are not light-transmitting.

[0035] Based on the above design, NA and focal length are designed. NA is designed to be greater than or equal to 0.2, and calculated according to NA = D / f, where D is the lens diameter and f is the focal length. Taking a lens with a diameter of 100um as an example, parallel light enters the microlens array, and its focal length is 500um. Figure 1 and Figure 2 shown.

[0036] Also disclosed is a surface optical fiber array, comprising: a surface optical fiber array having a positioning substrate, the optical fibers of the surface optical fiber array being arranged in a 5×5 structure on the positioning substrate, the optical fiber receiving end face matching the light beam emitted by the lens; the diameter of the lens output light spot is smaller than the core diameter of the optical fiber.

[0037] The design of the area array fiber array takes into account the matching degree between the core diameter and the light spot. According to the arrangement of the microlens array, the area array fiber is also designed to be arranged in 5×5. The positioning substrate is made of single crystal silicon. The center interval between the optical fibers is 200um, and the light spot size is designed according to the lens size of 100um. In order to ensure the coupling efficiency of the system, the light beam emitted by the lens is matched with the receiving end face of the optical fiber as much as possible, that is, the diameter of the light spot emitted by the lens is as small as possible from the core diameter of the optical fiber.

[0038] At the same time, considering the back-end requirements, the optical fiber array uses multi-mode optical fiber with a core diameter of 50um, and the interface of the pigtail uses FC / APC (optical fiber connector). The specific design is as follows Figure 3As shown in the figure, the array optical fiber is arranged 5×5, and the center interval between optical fibers is 200um±1um. The deep photolithography technology in integrated circuits is used to create a high-precision positioning substrate. The outermost layer is protected by a stainless steel protection box with a size of 30mm×30mm and an opening of 8mm×8mm at the front end of the protection box. The pigtail is protected by a corrugated tube and a protection tube.

[0039] The substrate uses a single crystal silicon wafer, and there are two-dimensional tiny through holes on the substrate that are evenly arranged. Glue is applied at the end point of the two-dimensional microhole, and the glue needs to wrap the root of the optical fiber. The entire two-dimensional optical fiber array is placed in a high-temperature oven for baking at a temperature of 70℃~90℃ and a baking time of 90min~150min to completely solidify the glue; the end face of the two-dimensional optical fiber array is ground and polished; the end face detector is used to check the ground end face of the two-dimensional optical fiber array.

[0040] Microlens array and area array fiber is a technology that realizes the coupling of optical signals through microlens array. Microlens is a lens structure with micron size. The control of optical signal is realized by controlling the shape and position of the lens. It is a structure composed of multiple single microlenses arranged together according to a preset rule. The principle of microlens array fiber coupling: focus the optical signal through the microlens array to the corresponding lens array.

[0041] The two-dimensional optical fiber array includes: a two-dimensional micro-hole positioning plate, a metal shell and 25 optical fibers. The 5×5 optical fibers pass through the small holes and are fixed with adhesive, and the metal shell is used as a support and protective cover for the fibers.

[0042] The coupling method of the microlens array and the optical fiber array is also disclosed. The light source power is set to 10mw, the rear end of the light source is connected to a collimator, and the collimator spot size is 8mm. The construction diagram is as follows: Figure 4 In the actual construction of the optical path, the fixation of the lens and the optical fiber requires a specific clamp to clamp. The coupling steps are as follows:

[0043] a) Use an infrared light source to connect a one-to-four beam splitter, connect the four interfaces of the beam splitter to the four corners of the fiber array (1, 5, 21, 25), and roughly align the four corners of the lens with the four corners of the fiber array. Observe the rough alignment effect from one side of the lens array.

[0044] b) Use an infrared light source, connect a collimator, and confirm whether the light spot of the collimator covers the light transmission area of ​​the lens array.

[0045] c) Connect the light source to the collimator, connect the pigtails at the four corners of the fiber optic array to the optical power meter, and place the lens array close to the fiber optic array. Finely adjust the position of the collimator and the fiber optic array, and adjust the optical power at the four corners to be as even as possible and larger.

[0046] d) Pull apart the optical fiber array and adjust the position of the optical fiber array and the lens array to a distance of 500um.

[0047] e) Then make fine adjustments in different directions of the optical fiber array, starting with fine adjustments until the output optical power is maximum (i.e. the coupling loss is minimum). Level the optical power at the four corners and adjust it larger.

[0048] f) Record the optical power of the 25-channel optical fiber array at this time; move the position of the optical fiber array, and record the 25-channel optical power meter readings after axial and angular movement of different distances, and obtain the assembly tolerance as a subsequent reference.

[0049] In summary, the present invention adopts the design and coupling method of 5×5 optical fiber array and microlens. The microlens array is a structure composed of multiple micron-sized lenses arranged in a certain pattern. These microlenses can achieve precise control and focusing of optical signals by precisely controlling their shapes and positions. After coupling with the surface optical fiber array, fine regulation of optical signals can be achieved, and the coupling efficiency of optical signals between different optical fibers can be significantly improved. The coupling combination of the microlens array and the surface optical fiber array can improve the integration and stability of the system.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A microlens array, characterized in that: include: A microlens array, wherein the microlens array has a lens substrate, a plurality of detection areas are arranged on the lens substrate, and a spacing gap is arranged between two adjacent detection areas; The size of the lens substrate is in the range of 5mm×5mm to 10mm×10mm, and the detection area is 900μm×900μm to 900μm×900μm; There are 20-25 detection areas, and the detection areas are located at the center of the lens substrate. The area of ​​each detection area is about 100um×100um. The center points of adjacent detection areas are spaced 200um apart and are arranged in a 5×5 manner.

2. The microlens array according to claim 1, characterized in that: The lens is made of grade 0 fused quartz.

3. A surface optical fiber array, applied to the microlens array according to claim 1, characterized in that: include: A surface optical fiber array, wherein the surface optical fiber array has a positioning substrate, the optical fibers of the surface optical fiber array are arranged in a 5×5 structure on the positioning substrate, and the optical fiber receiving end face matches the light beam emitted by the lens; The diameter of the lens output light spot is smaller than the core diameter of the optical fiber.

4. The planar optical fiber array according to claim 3, characterized in that: The positioning substrate is made of single crystal silicon.

5. The planar optical fiber array according to claim 3, characterized in that: The center interval between two adjacent optical fibers is 200um±1um.

6. The planar optical fiber array according to claim 3, characterized in that: The optical fiber of the surface optical fiber array is selected as a multimode optical fiber with a core diameter of 50um, and the pigtail interface of the optical fiber is a fiber optic connector.

7. A method for coupling a microlens array to a surface optical fiber array, using the surface optical fiber array of claim 3, characterized in that: The coupling steps are as follows: a) Use an infrared light source to connect a one-to-four beam splitter, connect the four interfaces of the beam splitter to the four corners of the fiber array (1, 5, 21, 25), and roughly align the four corners of the lens with the four corners of the fiber array. Observe the rough alignment effect from one side of the lens array. b) Use an infrared light source, connect a collimator, and confirm whether the light spot of the collimator covers the light transmission area of ​​the lens array; c) Connect the light source to the collimator, connect the pigtails at the four corners of the fiber array to the optical power meter, close the lens array to the fiber array, finely adjust the position of the collimator and the fiber array, and average the optical power at the four corners; d) Pull apart the optical fiber array and adjust the position of the optical fiber array and the lens array to a distance of 500um; e) Then make fine adjustments to the fiber array in different directions and start fine-tuning until the output optical power is maximum; Level the optical power at the four corners; f) Record the optical power of the 25-channel optical fiber array at this time; move the position of the optical fiber array, and record the 25-channel optical power meter readings after axial and angular movement of different distances, and obtain the assembly tolerance as a subsequent reference.

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