CN211552729U - MEMS multi-beam interference cavity based on plum blossom type optical fiber - Google Patents

Abstract

The utility model relates to a MEMS multi-beam interference cavity based on a quincunx optical fiber, comprising a quincunx optical fiber, a guide hole, a supporting frame, a hole shoulder, an interference cavity body, a sensitive diaphragm, a first reflection layer and a second reflection layer; The quincunx optical fiber includes a central optical fiber and a surrounding optical fiber; the quincunx optical fiber is fixed in the guide hole and connected with the second reflection layer, the center optical fiber is aligned with the center of the first reflection layer, and the surrounding optical fiber is Connected with the second reflective layer, the second reflective layer is arranged on the hole shoulder formed by the bottom of the guide hole and the interference cavity body, the interference cavity body is arranged at the bottom of the guide hole and is coaxial with the center of the guide hole, so The sensitive diaphragm is fabricated on the bottom of the interference cavity body and connected with the support frame, and the first reflection layer is arranged on the sensitive diaphragm. Compared with the prior art, the utility model has the advantages of less technological process, low processing difficulty, flexible structure design, low manufacturing cost and the like.

Description

MEMS multi-beam interference cavity based on quincunx fiber

technical field

The utility model relates to the field of optical fiber sensing, in particular to a MEMS multi-beam interference cavity based on a quincunx optical fiber.

Background technique

With the introduction of concepts such as Industry 4.0 and Made in China 2025, industrial production is gradually moving towards intelligence and informatization, and sensor technology is also facing challenges in miniaturization, intelligence, stability, and sensitivity. Sensors based on optical fiber interference cavity have the advantages of high sensitivity, anti-electromagnetic interference, and long transmission distance. Micro-Electro-Mechanical System (MEMS) is an electro-mechanical device developed on the basis of semiconductor technology. It has the characteristics of miniaturization, integration, multi-functionalization and intelligence. Technologies such as thin film deposition, LIGA, silicon micromachining, non-silicon micromachining, and precision machining are widely used in high-tech industries. Optical fiber interference cavity based on MEMS technology has the unique advantages of diverse structural design, wide selection of sensitive diaphragm materials, and high interference sensitivity. It is widely used in the detection of physical and chemical quantities such as temperature, pressure, sound wave, concentration, etc. Research hotspots in the field of sense.

In 2009, Guan Xile et al. (Research on Optical Fiber Dynamic Strain Sensing Technology [D]. University of Electronic Science and Technology of China, 2009.) proposed an enamel enamel composed of two optical flat plates with high reflection films on their end faces and strictly parallel to each other. Perspective interference cavity, which uses vacuum coating technology to coat the perforated quartz fiber end face and the cut and polished quartz end face with metallic chromium (Cr) with a thickness of about 0.3 μm as a reflective film, striving to achieve the maximum reflectivity and improve the enamel cavity. However, this method of increasing the reflectivity of the interference cavity is cumbersome, difficult to ensure processing consistency, and has poor flexibility. In 2010, Sun Dong et al. proposed a micro-fiber Fibonacci cavity fabricated with a 157nm wavelength laser (Acta Photonica Sinica, 2010, 39(07): 1239-1242), which utilizes a microchannel fabricated by a 157nm laser to connect the measured medium. Introduce the faeber cavity at the top of the single-mode fiber. In order to increase the contrast of the faeber cavity, it also adopts the method of coating the reflective surface of the faeber cavity with a high-reflection film, but this method is more difficult to process in this process. The operation is more complicated. In 2012, Akkaya O.C. et al. proposed a fiber-optic Fibonacci interference cavity for acoustic wave detection (J.Microelectromech.S., 2012, 21(6):1347-1356), which works by etching photons on a silicon film The crystal method is used to increase the reflectivity of the silicon surface and improve the interference quality of the Fibonacci cavity. Although this design can reduce the process of coating the silicon surface, the overall process of the preparation is complex, the process is difficult, and the cost is high. At the same time, the sensor The assembly is also more complicated.

In short, when constructing optical fiber interference cavity, related researches all improve the interference quality of the interference cavity by depositing reflection enhancement films on the two reflection surfaces of the interference cavity. larger.

Utility model content

The purpose of the present utility model is to provide a MEMS multi-beam interference cavity based on a quincunx fiber in order to overcome the above-mentioned defects of the prior art.

The purpose of the present utility model can be achieved through the following technical solutions:

A MEMS multi-beam interference cavity based on a quincunx optical fiber, comprising a quincunx optical fiber, a guide hole, a supporting frame, a hole shoulder, an interference cavity body, a sensitive diaphragm, a first reflection layer and a second reflection layer; the quincunx optical fiber Including center fiber and surround fiber;

The plum-shaped optical fiber is fixed in the guide hole and connected with the second reflection layer, the center optical fiber is aligned with the center of the first reflection layer, the surrounding optical fiber is connected with the second reflection layer, and the Two reflective layers are arranged on the hole shoulder formed by the bottom of the guide hole and the interference cavity body, the interference cavity body is arranged at the bottom of the guide hole and is coaxial with the center of the guide hole, and the sensitive diaphragm is made at the bottom of the interference cavity body and connected with the supporting frame, the first reflective layer is arranged on the sensitive diaphragm.

Preferably, the distance between the sensitive diaphragm and the end face of the quincunx fiber is controlled by the length of the interference cavity body.

Preferably, the quincunx optical fibers are arranged in a manner that N-1 surrounding optical fibers are evenly distributed around the circumference of one central optical fiber.

Preferably, the N is 5.

Preferably, the N is 9.

Preferably, the guide holes, the support frame, the hole shoulders, the interference cavity body, and the sensitive diaphragm are all made by dry etching or wet etching of silicon wafers, silicon oxide wafers, silicon nitride wafers, and SOI wafers. made parts.

Preferably, the first reflective layer is a component made of materials of gold, silver and aluminum by evaporation or magnetron sputtering.

Preferably, the second reflective layer is a component made of materials of gold, silver and aluminum by evaporation or magnetron sputtering.

Compared with the prior art, the utility model realizes the construction of the optical fiber interference cavity and the optimization of its interference quality by combining the quincunx optical fiber and the high reflectivity stepped hole, which is different from the traditional method of optimizing the interference quality of the interference cavity by the precipitation process. This method of optimizing the interference quality of the interference cavity by increasing the number of reflective fibers and optimizing the splitting ratio of the beam splitter simplifies the process of separately coating the fiber end face and the surface of the sensitive diaphragm, and only needs one coating to increase the interference cavity at the same time. The reflectivity of the two reflective surfaces can optimize the interference quality of the interference cavity, and has the advantages of less process flow, low processing difficulty, flexible structure design, and low production cost. It can greatly improve the assembly efficiency of the interference cavity; in addition, the optical fiber interference cavity using the MEMS process also has the advantages of small size, light weight, high degree of integration, and mass production. MEMS multi-beam interference cavity will contribute to the application and promotion of optical fiber interference cavity in more fields.

Description of drawings

1 is a schematic structural diagram of a MEMS multi-beam interference cavity based on a quincunx fiber of the present invention;

FIG. 2 is a schematic structural diagram of a quincunx optical fiber fabricated by processing N optical splitting ports of a 1×N optical splitter;

Fig. 3 is the sectional structure schematic diagram of the B-B direction of Fig. 2;

FIG. 4 is a schematic structural diagram of a plum-shaped optical fiber fabricated by processing five optical splitting ports of a 1×5 optical splitter;

Fig. 5 is the sectional structure schematic diagram of the B-B direction of Fig. 4;

FIG. 6 is a schematic structural diagram of a plum-shaped optical fiber fabricated by processing five optical splitting ports of a 1×9 optical splitter;

FIG. 7 is a schematic cross-sectional structure diagram of the B-B direction of FIG. 6;

FIG. 8 is a schematic diagram of forming a guide hole on a silicon oxide wafer by wet etching;

9 is a schematic diagram of fabricating a sensitive diaphragm and forming an interference cavity body by wet etching at the bottom of the guide hole;

FIG. 10 is a schematic diagram of the formation of the first reflection layer and the second reflection layer.

1 is the plum-shaped fiber, 2 is the guide hole, 3 is the support frame, 4 is the hole shoulder, 5 is the interference cavity body, 6 is the sensitive diaphragm, 7 is the first reflection layer, 8 is the second reflection layer, and 9 is the center Optical fiber, 10 is a surrounding optical fiber.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are a part of the embodiments of the present utility model, rather than all the embodiments. . Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Example 1

The overall structure of the MEMS multi-beam interference cavity based on the quincunx optical fiber proposed by the present utility model is shown in FIG. Sheet 6 , first reflective layer 7 , second reflective layer 8 , central optical fiber 9 and surrounding optical fiber 10 .

The quincunx optical fiber 1 is fixed in the guide hole 2 and connected with the second reflection layer 8, the central optical fiber 9 in the quincunx optical fiber 1 is aligned with the center of the first reflection layer 7, and the quincunx optical fiber 1 is aligned with the center of the first reflection layer 7. The surrounding optical fiber 10 in the optical fiber 1 is connected to the second reflection layer 8, and the second reflection layer 8 is made on the hole shoulder 4 formed by the bottom of the guide hole 2 and the interference cavity body 5, and the interference cavity body 5 is made on the guide hole 2. The bottom of the hole 2 is coaxial with the center of the guide hole 2 , the sensitive diaphragm 6 is made on the bottom of the interference cavity body 5 and connected to the support frame 3 , and the first reflective layer 7 is made on the sensitive diaphragm 6 , the distance between the sensitive diaphragm 6 and the end face of the quincunx fiber 1 is controlled by the length of the interference cavity body 5 .

Referring to FIG. 2 , the quincunx fiber 1 is fabricated by processing N optical splitting ports of a 1×N optical splitter (N=2, 3, 4...), and referring to the view of FIG. 3 , the interior of the quincunx fiber 1 N-1 surrounding optical fibers 10 are arranged evenly around a central optical fiber 9. The number of beam splitters and the split ratio of the beam splitters are determined according to the reflectivity and fineness required by the actual interference cavity.

The guide hole 2, the support frame 3, the hole shoulder 4, the interference cavity body 5 and the sensitive diaphragm 6 are dry-etched or wet-etched for silicon wafers, silicon oxide wafers, silicon nitride wafers, SOI (Silicon-On- Insulator) sheet and other materials are made as a whole.

The first reflective layer 7 and the second reflective layer 8 can be made of materials such as gold, silver, and aluminum by evaporation or magnetron sputtering.

The sensing principle of the interference cavity is: the light emitted by the light source enters the beam splitter through the optical fiber circulator, and is divided into N beams of light by the beam splitter, of which N-1 beams enter the surrounding optical fiber 10 and are reflected by the second reflective layer 8 at the bottom of the guide hole 2. The remaining beam of light enters the central optical fiber 9 and is reflected by the first reflective layer 7 on the sensitive diaphragm 6 and re-enters the optical fiber. The N part of the beams converge and interfere in the beam splitter, and the converged and interfered beams enter the rear end through the fiber circulator. Detection Systems. The interference signal is related to the cavity length of the interference cavity body 5. When the detected signal causes the sensitive diaphragm 6 to deform axially, the cavity length of the interference cavity body 5 changes, thereby causing the interference signal to change. Information about the measured physical quantity can be obtained.

The basic machining process of the interference cavity is as follows:

Step 1: Referring to FIG. 8, the guide holes 2 are formed on materials such as silicon wafers, silicon oxide wafers, silicon nitride wafers, SOI (Silicon-On-Insulator) wafers, etc. by dry etching or wet etching;

Step 2: Referring to FIG. 9, at the bottom of the guide hole 2, the sensitive diaphragm 6 is fabricated by dry etching or wet etching and other processes, and the interference cavity body 5 is formed;

Step 3: Referring to FIG. 10, deposit the first reflective layer 7 and the second reflective layer 8 on the upper part of the sensitive diaphragm 6 and the aperture shoulder 4 by vapor deposition or magnetron sputtering of gold, silver, aluminum and other materials;

Step 4: Insert the quincunx optical fiber 1 into the guide hole 2, locate the fiber end face through the hole shoulder 4, align the center fiber 9 inside the quincunx optical fiber 1 with the center of the first reflection layer 7 on the sensitive diaphragm 6, and the quincunx optical fiber The surrounding optical fiber 10 inside 1 is in contact with the second reflective layer 8 on the hole shoulder 4, and the quincunx fiber 1 is fixed in the guide hole 2 by adhesives such as epoxy resin and hot melt adhesive to form a multi-beam fiber interference cavity.

Example 2

The overall structure of the MEMS multi-beam interference cavity based on the quincunx optical fiber proposed by the present utility model is shown in FIG. Sheet 6 , first reflective layer 7 , second reflective layer 8 , central optical fiber 9 and surrounding optical fiber 10 .

The quincunx optical fiber 1 is fixed in the guide hole 2 and connected with the second reflection layer 8, the central optical fiber 9 in the quincunx optical fiber 1 is aligned with the center of the first reflection layer 7, and the quincunx optical fiber 1 is aligned with the center of the first reflection layer 7. The surrounding optical fiber 10 in the optical fiber 1 is connected to the second reflection layer 8, and the second reflection layer 8 is made on the hole shoulder 4 formed by the bottom of the guide hole 2 and the interference cavity body 5, and the interference cavity body 5 is made on the guide hole 2. The bottom of the hole 2 is coaxial with the center of the guide hole 2 , the sensitive diaphragm 6 is made on the bottom of the interference cavity body 5 and connected to the support frame 3 , and the first reflective layer 7 is made on the sensitive diaphragm 6 , the distance between the sensitive diaphragm 6 and the end face of the quincunx fiber 1 is controlled by the length of the interference cavity body 5 .

Referring to FIG. 4 , the quincunx fiber 1 is made by processing 5 optical splitting ports of a 1×5 optical splitter, and the splitting ratio adopts an equal division method. Referring to the view of FIG. 5 , the quincunx optical fiber 1 adopts four surrounding The optical fibers 10 are arranged in a circumferentially uniform manner around the central optical fiber 9 .

The guide hole 2 , the support frame 3 , the hole shoulder 4 , the interference cavity body 5 and the sensitive diaphragm 6 are integrally fabricated by dry etching a silicon wafer.

The first reflective layer 7 and the second reflective layer 8 are fabricated by evaporating gold.

The sensing principle of the interference cavity is: the light emitted by the light source enters the beam splitter through the optical fiber circulator, and is split into the optical fiber by the optical splitter. , these 5 parts of the beams converge and interfere in the beam splitter, and the beams after the convergence and interference enter the back-end detection system through the fiber circulator. The interference signal is related to the cavity length of the interference cavity body 5. When the detected signal causes the sensitive diaphragm 6 to deform axially, the cavity length of the interference cavity body 5 changes, thereby causing the interference signal to change. Information about the measured physical quantity can be obtained.

The basic machining process of the interference cavity is as follows:

Step 1: Referring to FIG. 8 , the guide hole 2 is formed on the silicon wafer by dry etching;

Step 2: Referring to FIG. 9 , dry etching is performed to form the sensitive diaphragm 6 at the bottom of the guide hole 2 and the interference cavity body 5 is formed;

Step 3: Referring to FIG. 10 , deposit the first reflective layer 7 and the second reflective layer 8 on the upper part of the sensitive diaphragm 6 and the aperture shoulder 4 by evaporating gold;

Step 4: Insert the quincunx optical fiber 1 into the guide hole 2, locate the fiber end face through the hole shoulder 4, align the center fiber 9 of the quincunx optical fiber 1 with the center of the first reflection layer 7 on the sensitive diaphragm 6, and the quincunx optical fiber 1 The surrounding optical fiber 10 is in contact with the second reflective layer 8 on the hole shoulder 4, and the quincunx fiber 1 is fixed in the guide hole 2 by epoxy resin to form a multi-beam fiber interference cavity.

Example 3:

The overall structure of the MEMS multi-beam interference cavity based on the quincunx optical fiber proposed by the present utility model is shown in FIG. Sheet 6 , first reflective layer 7 , second reflective layer 8 , central optical fiber 9 and surrounding optical fiber 10 .

The quincunx optical fiber 1 is fixed in the guide hole 2 and connected with the second reflection layer 8, the central optical fiber 9 in the quincunx optical fiber 1 is aligned with the center of the first reflection layer 7, and the quincunx optical fiber 1 is aligned with the center of the first reflection layer 7. The surrounding optical fiber 10 in the optical fiber 1 is connected to the second reflection layer 8, and the second reflection layer 8 is made on the hole shoulder 4 formed by the bottom of the guide hole 2 and the interference cavity body 5, and the interference cavity body 5 is made on the guide hole 2. The bottom of the hole 2 is coaxial with the center of the guide hole 2 , the sensitive diaphragm 6 is made on the bottom of the interference cavity body 5 and connected to the support frame 3 , and the first reflective layer 7 is made on the sensitive diaphragm 6 , the distance between the sensitive diaphragm 6 and the end face of the quincunx fiber 1 is controlled by the length of the interference cavity body 5 .

Referring to FIG. 6 , the quincunx fiber 1 is fabricated by processing 9 optical splitting ports of a 1×9 optical splitter, and the splitting ratio adopts an equal division method. Referring to the view of FIG. 7 , the quincunx optical fiber 1 is made of 9 surrounding optical fibers. The optical fibers 10 are arranged in a circumferentially uniform manner around the central optical fiber 9 .

The guide hole 2 , the support frame 3 , the hole shoulder 4 , the interference cavity body 5 and the sensitive diaphragm 6 are integrally fabricated by wet etching a silicon oxide wafer.

The first reflective layer 7 and the second reflective layer 8 can be fabricated by magnetron sputtering gold.

The sensing principle of the interference cavity is: the light emitted by the light source enters the beam splitter through the optical fiber circulator, and is divided into 9 beams of light by the beam splitter, of which 8 beams enter the surrounding optical fiber 10 and are reflected by the second reflective layer 8 at the bottom of the guide hole 2 into the optical fiber. , the remaining beam of light enters the central fiber 9 and is reflected by the first reflective layer 7 on the sensitive diaphragm 6 and re-enters the fiber. These 9 parts of the beams converge and interfere in the beam splitter, and the converged and interfered beams enter the back end through the fiber circulator for detection system. The interference signal is related to the cavity length of the interference cavity body 5. When the detected signal causes the sensitive diaphragm 6 to deform axially, the cavity length of the interference cavity body 5 changes, thereby causing the interference signal to change. Information about the measured physical quantity can be obtained.

The basic machining process of the interference cavity is as follows:

Step 1: Referring to 8, make the guide hole 2 on the silicon oxide wafer by wet etching;

Step 2: Referring to 9, at the bottom of the guide hole 2, the sensitive diaphragm 6 is formed by wet etching and the interference cavity body 5 is formed;

Step 3: Referring to 10, deposit the first reflection layer 7 and the second reflection layer 8 on the upper part of the sensitive diaphragm 6 and the hole shoulder 4 by magnetron sputtering gold;

Step 4: Insert the quincunx optical fiber 1 into the guide hole 2, locate the fiber end face through the hole shoulder 4, align the center fiber 9 of the quincunx optical fiber 1 with the center of the first reflection layer 7 on the sensitive diaphragm 6, and the quincunx optical fiber 1 The surrounding optical fiber 10 is in contact with the second reflective layer 8 on the hole shoulder 4, and the quincunx fiber 1 is fixed in the guide hole 2 by hot melt adhesive to form a multi-beam fiber interference cavity.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Equivalent modifications or replacements should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (8)

1. a MEMS multi-beam interference cavity based on a quincunx optical fiber, is characterized in that, comprises quincunx optical fiber (1), guide hole (2), support frame (3), hole shoulder (4), interference cavity body (5) ), a sensitive diaphragm (6), a first reflection layer (7) and a second reflection layer (8); the quincunx optical fiber (1) includes a central optical fiber (9) and a surrounding optical fiber (10); The plum-shaped optical fiber (1) is fixed in the guide hole (2) and connected with the second reflection layer (8), and the center optical fiber (9) is aligned with the center of the first reflection layer (7), so The said encircling optical fiber (10) is connected with the second reflection layer (8), and the second reflection layer (8) is arranged on the hole shoulder (4) formed by the bottom of the guide hole (2) and the interference cavity body (5). , the interference cavity body (5) is arranged at the bottom of the guide hole (2) and is coaxial with the center of the guide hole (2), and the sensitive diaphragm (6) is made at the bottom of the interference cavity body (5) and is aligned with the center of the guide hole (2). The supporting frame (3) is connected, and the first reflective layer (7) is arranged on the sensitive diaphragm (6). 2. A MEMS multi-beam interference cavity based on a quincunx optical fiber according to claim 1, wherein the distance between the sensitive diaphragm (6) and the end face of the quincunx optical fiber (1) passes through the interference cavity body (5) length control. 3. a kind of MEMS multi-beam interference cavity based on quincunx optical fiber according to claim 1, is characterized in that, described quincunx optical fiber (1) adopts N-1 surrounding optical fibers (10) to surround 1 central optical fiber ( 9) Arranged in an evenly distributed manner. 4 . The MEMS multi-beam interference cavity based on a quincunx fiber according to claim 3 , wherein the N is 5. 5 . 5 . The MEMS multi-beam interference cavity based on a quincunx fiber according to claim 3 , wherein the N is 9. 6 . 6. A MEMS multi-beam interference cavity based on a quincunx fiber according to claim 1, wherein the guide hole (2), the support frame (3), the hole shoulder (4), the interference cavity body ( 5) The sensitive diaphragms (6) are all components made by dry etching or wet etching of silicon wafers, silicon oxide wafers, silicon nitride wafers, and SOI wafers as a whole. 7. The MEMS multi-beam interference cavity based on quincunx fiber according to claim 1, wherein the first reflection layer (7) is made of gold, silver, and aluminum by evaporation or magnetron sputtering. parts made of materials. 8. A MEMS multi-beam interference cavity based on a quincunx optical fiber according to claim 1, wherein the second reflection layer (8) is made of gold, silver, and aluminum by evaporation or magnetron sputtering. parts made of materials.

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