High-power MOEMS optical switch integrated with coated optical fiber and plug-in mounting and fixing method of high-power MOEMS optical switch

Abstract

The invention discloses a high-power MOEMS optical switch integrated with a coated optical fiber and a plug-in mounting and fixing method of the high-power MOEMS optical switch. The high-power MOEMS optical switch comprises a shell, a chip arranged in the shell and an optical fiber set inserted into the chip through an optical fiber guide pipe. The optical fiber group comprises an input optical fiber and an output optical fiber; the output end face of the input optical fiber and the input end face of the output optical fiber are each provided with three film layers to improve the laser thermal damage resistance of the end faces of the optical fibers, the first layer is made of a low-refractive-index material SiO2, the second layer is made of a high-refractive-index material HfO2, and the third layer is made of SiO2. According to the method, the optical fiber film layer can be prevented from being scratched, peeled off or polluted in the assembling process, the risks of optical axis deviation and bare fiber breakage are reduced, the packaging stability of the MOEMS optical switch in high-power laser transmission is improved, and the service life of the MOEMS optical switch in high-power laser transmission is prolonged.

Description

Technical Field

[0001] The present invention belongs to the field of micro-optical electromechanical systems, and in particular to a high-power MOEMS optical switch integrating a coated optical fiber and a plug-in fixing method thereof. Background Art

[0002] As a key component in micro-laser control systems, MOEMS optical switches are widely used in laser fuses, signal distribution, and photoelectric conversion. Their operation requires high-energy laser light to be introduced through an optical fiber and then achieved through mechanical switching to achieve isolation and conduction.

[0003] With the widespread application of semiconductor lasers in industrial processing, biomedicine and other fields, fiber laser transmission systems have become an important means of achieving flexible laser transmission. Among them, 808nm lasers, as typical pump sources or photothermal sources, are widely coupled into multimode optical fibers for transmission. However, when the laser power exceeds a certain threshold, the fiber end face is prone to ablation, blackening, or even breakage due to reflected heat accumulation, local absorption, or surface contamination. This not only limits the reliability of optical fibers in high-power applications, but also affects the optical path quality and the service life of MOEMS optical switches. In order to improve the high-power tolerance of the fiber end face, anti-reflection coating structures are often used to reduce reflectivity and heat accumulation.

[0004] However, during the integration of coated optical fibers with microstructured chips, the end-face coating is easily damaged during the insertion operation. Traditional assembly methods often lack effective alignment and limiting mechanisms, and the fiber is prone to lateral displacement or angular deviation during the insertion process, causing friction between the coating and the inner wall of the channel, resulting in scratches, peeling, or contamination of the coating. In addition, some packaging structures do not have out-of-plane limiting surfaces, and the optical fiber may drift during assembly, transportation, or operation, reducing the accuracy of optical alignment and affecting the long-term stability of the package.

[0005] Therefore, there is an urgent need in the existing technology for a technical solution that can balance high-power tolerance performance and assembly protection performance, that is, while having a high-performance anti-reflection film structure, a high-precision, low-damage optical fiber insertion and fixation method is adopted to meet the reliable application requirements of high-power MOEMS optical switches. Summary of the Invention

[0006] The present invention aims to provide a high-power MOEMS optical switch with integrated coated optical fiber and a method for its insertion and fixation. This switch can achieve high-precision alignment and reliable packaging of the optical fiber and microstructure chip while maintaining the high-power tolerance performance of the optical fiber end face, avoiding film damage and optical axis deviation during assembly, and improving the long-term stability and transmission reliability of the system.

[0007] The technical solutions for achieving the purpose of the present invention are:

[0008] A high-power MOEMS optical switch with integrated coated optical fiber, comprising a housing, a chip disposed in the housing, and an optical fiber group inserted into the chip through an optical fiber conduit; the optical fiber group comprises an input optical fiber and an output optical fiber;

[0009] The output end face of the input optical fiber and the input end face of the output optical fiber are both provided with three layers of coating to enhance the resistance of the optical fiber end face to laser thermal damage, wherein:

[0010] The first layer is SiO2, a low-refractive-index material with a thickness of approximately 137-141 nm.

[0011] The second layer is a high refractive index material HfO2 with a thickness of about 99-103nm;

[0012] The third layer is SiO2 with a thickness of about 137-141nm.

[0013] A method for inserting and fixing a high-power MOEMS optical switch for an integrated coated optical fiber, comprising:

[0014] S1: Complete chip bonding and form an out-of-plane limiting interface;

[0015] S2: Install the coated input and output optical fibers on two 3D platforms. Adjust the X, Y, and Z positions of the fiber ends to ensure alignment between the fiber axis and the microchannels within the chip.

[0016] S3: While maintaining the collinear state, the optical fiber is inserted into the microchannel in the chip through the optical fiber guide tube in the ceramic housing. During the insertion process, there is no direct contact between the end face of the optical fiber and the inner wall of the channel;

[0017] S4: Inject UV curing glue through the glue hole reserved in the shell. The glue is filled between the optical fiber and the microchannel and is cured by UV irradiation to achieve stable fixation.

[0018] Compared with the prior art, the present invention has the following significant advantages:

[0019] (1) Combining a high-performance anti-reflection film structure with a precise insertion and fixing process, while improving the high-power tolerance of the optical fiber, ensure that the film layer is protected from mechanical friction and contamination during the assembly process;

[0020] (2) The use of glass caps to provide out-of-plane positioning, combined with the fine-tuning function of the three-dimensional high-precision platform, can significantly reduce the lateral offset and angular deviation during fiber insertion, ensuring optical alignment accuracy;

[0021] (3) The dispensing and curing process can achieve reliable fixation of the optical fiber and chip structure, improving the mechanical stability and long-term working reliability of the package;

[0022] (4) It is suitable for 105 / 125μm multimode quartz optical fiber and high-power 808nm semiconductor laser applications, and can be extended to fiber laser transmission systems of other wavelengths and power levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the three-layer anti-reflection coating structure on the optical fiber end face.

[0024] Figure 2 This is a schematic diagram of the three-dimensional model structure of the MOEMS optical switch chip.

[0025] Figure 3 This is a diagram of the MOEMS optical switch chip integrated optical fiber structure.

[0026] Figure 4 This is a cross-sectional diagram of a MOEMS optical switch.

[0027] Figure 5 This is a schematic diagram of the MOEMS optical switch integrated with optical fiber. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0029] Reference Figure 2-Figure 5 This embodiment provides a high-power MOEMS optical switch with integrated coated optical fiber, whose overall structure includes a chip 2, an optical fiber group 3, an optical fiber conduit 4, a dispensing hole 5, and a ceramic shell 6; the chip 2 includes a glass cap 2-1, a frame layer 2-2, an optical fiber microchannel 2-3, a structural layer 2-4, a support anchor point 2-5, and a base layer 2-6.

[0030] The chip 2 is mainly manufactured by DRIE process, using photoresist as sacrificial layer and silicon wafer as structural layer of the device, and undergoing multiple steps of masking, photolithography, etching, scribing, etc. to finally complete the manufacturing.

[0031] The glass cap 2-1 is directly bonded to the frame layer 2-2; the frame layer 2-2 is directly bonded to the base layer 2-6; two support anchors 2-5 are provided on the base layer 2-6; the structural layer 2-4 is fixed on the support anchors 2-5; the frame layer 2-2 is on the periphery of the structural layer 2-4.

[0032] The glass cap 2 - 1 is used to limit the out-of-plane movement of the optical fiber group 3 during the assembly process, and also limits the height of the optical fiber group 3 during assembly.

[0033] The optical fiber microchannel 2-3 is used to provide a fixed position for the optical fiber group 3 and limit the axial movement of the optical fiber. The optical fiber microchannel 2-3 is directly bonded to the base layer 2-6 and attached to the frame layer 2-2; the optical fiber microchannel 2-3 is at the same height as the optical fiber conduit 4 to avoid bending or breaking of the optical fiber during the integration process due to the height difference.

[0034] The optical fiber group 3 includes an input optical fiber 3-1 and an output optical fiber 3-2; an offset position and an alignment position are provided between the output end of the input optical fiber 3-1 and the input end of the output optical fiber 3-2; when the optical switch is in a safe state, the output end of the input optical fiber 3-1 remains offset from the output optical fiber 3-2, thereby isolating the laser; when the optical switch is in a standby state, the output end of the input optical fiber 3-1 remains aligned with the input end of the output optical fiber 3-2, thereby achieving high-power laser conduction; the input end of the input optical fiber 3-1 is coupled to a laser generator, and the output end of the output optical fiber 3-2 is coupled to a laser initiator.

[0035] The output end of the input optical fiber 3-1 and the input end of the output optical fiber 3-2 are both coated. The coating structure is used to improve the anti-reflection performance and thermal damage threshold during 808nm wavelength laser transmission and is suitable for 105 / 125μm multimode quartz optical fiber end faces. Figure 1 The antireflection coating 1, from the air side toward the fiber end face (substrate), comprises: SiO2 layer 1-1 (low refractive index layer, L), approximately 137-141 nm thick; HfO2 layers 1-2 (high refractive index layers, H layers), approximately 99-103 nm thick; and SiO2 layers 1-3 (low refractive index layers, L layers), also approximately 137-141 nm thick. Quartz fiber end faces 1-4 are exposed multimode quartz fiber glass end faces.

[0036] The three coating layers have a total thickness of approximately 379nm, with a designed central wavelength of 808nm. Multilayer interference reduces the reflectivity at this wavelength to below 0.2%, thereby improving the fiber endface's resistance to laser thermal damage. The coating is formed using an ion beam-assisted deposition process to enhance density and adhesion, with a controlled thickness error of less than ±5nm.

[0037] The three-layer film structure is an LHL anti-reflection film design. Its operating principle is to utilize the optical interference effect between multiple thin films to offset the phase of light waves reflected from the interfaces of different film layers, thereby significantly reducing the reflectivity at specific wavelengths. Based on the refractive index parameters of the selected materials, the refractive index of SiO2 is approximately 1.45 and the refractive index of HfO2 is approximately 2.0. Combined with the designed central wavelength λ = 808nm, the physical thickness of each film layer is determined according to the quarter-path principle, that is, the optical thickness meets the requirement of λ / 4n, where λ is the central wavelength (unit: nm) and n is the refractive index of the film material.

[0038] The coated optical fiber group 3 is inserted into the optical fiber microchannel 2-3 of the chip through the optical fiber guide tube 4. During the insertion process, the coated end face is kept away from contact with the inner wall of the channel. The insertion adopts a three-dimensional high-precision platform 7 to ensure that the optical fiber group 3 and the microchannel 2-2 are collinear.

[0039] The ceramic housing 6 is provided with a glue dispensing hole 5, which is used to inject ultraviolet curing glue to achieve a stable connection between the optical fiber group 3 and the chip structure.

[0040] The ceramic housing 6 is an optical switch packaging shell, and has the characteristics of high strength and high reliability.

[0041] The three-dimensional high-precision platform 7 is used to achieve spatial alignment between the optical fiber group 3 and the optical fiber microchannel 2-3. Through precise adjustment and slow insertion process, it effectively avoids the risk of optical fiber breakage due to inaccurate alignment or interference during insertion; effectively prevents the optical fiber end face from contacting the inner wall of the chip microchannel, and avoids scratches, shedding or contamination of the film layer.

[0042] To achieve reliable integration between the coated optical fiber and the MOEMS optical switch chip, the following assembly process is used:

[0043] S1: The frame layer 2-2 is bonded to the glass cap 2-1; the glass cap 2-1 is installed before the optical fiber group 3 is integrated. Its function is to provide a stable out-of-plane direction restriction surface for the optical fiber to prevent the optical fiber from generating angular deviation or vertical displacement during the subsequent insertion process.

[0044] S2: The input optical fiber 3-1 and the output optical fiber 3-2 that have completed the coating process are respectively installed on two three-dimensional high-precision platforms 7, and the ceramic shell 6 is fixed; by fine-tuning the X, Y, and Z directions of the three-dimensional high-precision platform 7, the optical fiber axis and the microchannel 2-3 in the chip are kept precisely collinear.

[0045] S3: While maintaining the alignment, slowly insert the input optical fiber 3-1 and the output optical fiber 3-2 into the chip microchannel to ensure that the anti-reflection film layer 1 smoothly passes through the optical fiber conduit 4 and the microchannel hole 2-3 in the chip structure. During the process, avoid contact between the anti-reflection film layer 1 and the inner wall to prevent the film layer from being scratched, peeled off or contaminated, while reducing the risk of breakage of the bare fiber segment due to position offset or assembly interference.

[0046] S4: After the optical fiber is in place, UV-curable adhesive is injected through the pre-reserved dispensing hole 5 on the side of the ceramic housing 6. The adhesive is introduced through a dispensing needle or microtube and then fills the gap between the optical fiber conduit 4 and the microchannel 2-3. 365nm UV light is used to cure the adhesive, forming a high-strength adhesive layer, which securely fixes the optical fiber to the chip.

[0047] Finally, the input optical fiber 3-1 and the output optical fiber 3-2 are accurately integrated in the microchannel 2-3, with the end face remaining intact and the film layer intact. The UV glue is firmly fixed and the position is stable, with excellent laser transmission performance and structural reliability.

Claims

1. A high-power MOEMS optical switch with integrated coated optical fiber, comprising a housing, a chip disposed within the housing, and an optical fiber assembly inserted into the chip via an optical fiber conduit; the optical fiber assembly comprises an input optical fiber and an output optical fiber; characterized in that: The output end face of the input optical fiber and the input end face of the output optical fiber are both provided with three layers of coating to enhance the resistance of the optical fiber end face to laser thermal damage, wherein: The first layer is SiO2, a low-refractive-index material with a thickness of approximately 137-141 nm. The second layer is a high refractive index material HfO2 with a thickness of about 99-103nm; The third layer is SiO2 with a thickness of about 137-141nm.

2. The high-power MOEMS optical switch with integrated coated optical fiber according to claim 1, characterized in that: The central wavelength of the three-layer film is 808nm.

3. The high-power MOEMS optical switch with integrated coated optical fiber according to claim 1, characterized in that: The film layer is formed by ion beam assisted deposition process, and the film thickness control error is less than ±5nm.

4. The high-power MOEMS optical switch with integrated coated optical fiber according to claim 1, characterized in that: The chip includes a base layer, a frame layer bonded to the base layer, a glass cap bonded to the frame layer, two support anchors located on the base layer, and a structural layer fixed on the support anchors; the glass cap is used to limit the out-of-plane movement of the optical fiber group during the assembly process and limit the height of the optical fiber group during assembly; the optical fiber microchannel is used to provide a fixed position for the optical fiber group and limit the axial movement of the optical fiber.

5. The high-power MOEMS optical switch with integrated coated optical fiber according to claim 1, characterized in that: The optical fiber microchannel and the light conduit are at the same height.

6. The high-power MOEMS optical switch with integrated coated optical fiber according to claim 1, characterized in that: The optical fiber is a 105 / 125 μm multimode quartz optical fiber.

7. A method for inserting and fixing a high-power MOEMS optical switch with an integrated coated optical fiber according to any one of claims 1 to 5, characterized in that: include: S1: Complete chip bonding and form an out-of-plane limiting interface; S2: Install the coated input and output optical fibers on two 3D platforms. Adjust the X, Y, and Z positions of the fiber ends to ensure alignment between the fiber axis and the microchannels within the chip. S3: While maintaining the collinear state, the optical fiber is inserted into the microchannel in the chip through the optical fiber guide tube in the ceramic housing. During the insertion process, there is no direct contact between the end face of the optical fiber and the inner wall of the channel; S4: Inject UV curing glue through the glue hole reserved in the shell. The glue is filled between the optical fiber and the microchannel and is cured by UV irradiation to achieve stable fixation.

8. The insertion and fixing method according to claim 7, characterized in that: The UV curing glue is injected through the dispensing needle and cured by 365nm wavelength UV light.

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