A mode matching device based on spatial coupling

Abstract

The application relates to a mode matching device based on spatial coupling, which comprises a first optical fiber fixing part, a packaging module and a second optical fiber fixing part; the first optical fiber fixing part is installed on the input side of the packaging module and is used for installing a first optical fiber and inputting input light after adjustment; the second optical fiber fixing part is installed on the output side of the packaging module and is used for installing a second optical fiber and inputting output light of the packaging module after adjustment; the packaging module comprises a first dichroic mirror and a light signal adjustment assembly arranged in sequence along the light propagation direction; the first dichroic mirror is used for filtering pump light in the input light; and the light signal adjustment assembly is used for outputting output light of the first dichroic mirror after adjustment to meet the input requirement of an optical fiber amplifier. The application is based on the mode of spatial coupling and can meet the high-fidelity transmission of high-power and high-energy laser; the structure is simple and additional loss is not easily introduced; the system thermal influence is reduced and the system stability is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser technology, in particular to a mode matching device based on spatial coupling. BACKGROUND

[0002] The mode field adapter is an important component in the field of ultrafast fiber lasers. In order to obtain higher energy ultra-short pulse laser, fiber lasers need to cascade multiple stages of fiber amplifiers. Due to the influence of fiber nonlinear effects (such as stimulated Raman, stimulated Brillouin, mode instability, etc.), as the laser pulse energy increases, the core diameter of the fiber amplifier also needs to be increased step by step. Each stage of the cascaded amplifier needs to use a fiber mode field adapter to achieve efficient coupling and mode matching to obtain higher amplification efficiency and laser mode, and to optimize the final spectrum and pulse width.

[0003] At present, the commonly used fiber mode field adapter mostly uses the fiber taper method to gradually reduce the fiber core diameter to match the parameters of the input signal fiber, such as fiber core diameter and numerical aperture, so as to reduce signal transmission loss during fiber fusion and mode noise, and to minimize the influence of high-order mode amplification after signal coupling on the final optical pulse quality. The ultrafast laser amplifier uses multiple specifications of optical fibers. The long passive optical fiber will increase the nonlinear phase shift in the long signal transmission, affecting the final ultra-short pulse laser compression quality.

[0004] In addition, the fiber mode field adapter of the fiber taper method has a relatively low power at the fusion point. When high-energy laser amplification is performed, a large amount of backward amplified signal, including back-reflection light, stimulated Raman, spontaneous radiation, and stimulated Brillouin signal, etc. may occur. High-energy high-power signals can cause irreversible damage to the fusion point or the mode field adapter, affecting the stability of the system. Especially when the photonic crystal fiber is used for tapering, the internal air hole structure limits the preparation of the taper combiner. Tapering causes the air hole to collapse and the array arrangement to change, affecting the numerical aperture and other optical parameters, and increasing the fusion loss. The above problems need to be solved. SUMMARY

[0005] The present application discloses a mode matching device based on spatial coupling, which aims to solve the technical problems existing in the prior art.

[0006] The present application adopts the following technical scheme:

[0007] The application provides a mode matching device based on spatial coupling, which comprises a first optical fiber fixing part, a packaging module and a second optical fiber fixing part; the first optical fiber fixing part is installed on the input side of the packaging module and is used for installing a first optical fiber and adjusting input light to input into the packaging module; the second optical fiber fixing part is installed on the output side of the packaging module and is used for installing a second optical fiber and adjusting the output light of the packaging module to input into the second optical fiber; the packaging module comprises a first dichroic mirror and an optical signal adjusting assembly arranged in sequence along the light propagation direction; the first dichroic mirror is used for filtering out pump light in the input light; the optical signal adjusting assembly is used for adjusting the output light of the first dichroic mirror to meet the input requirement of an optical fiber amplifier and then output.

[0008] In the mode matching device based on spatial coupling, the optical signal adjusting assembly comprises a first half-wave plate, a Faraday rotator, a second polarization beam splitter and a second half-wave plate arranged in sequence along the light propagation direction; the first half-wave plate and the Faraday rotator are used for adjusting the input light into horizontal polarization light; the second polarization beam splitter is used for transmitting the horizontal polarization light in the output light of the Faraday rotator into the second half-wave plate; and the second half-wave plate is used for adjusting the polarization direction of the horizontal polarization light to meet the input requirement of the optical fiber amplifier and then output.

[0009] In the mode matching device based on spatial coupling, the optical signal adjusting assembly further comprises a second dichroic mirror; the second dichroic mirror is arranged on the light path between the second polarization beam splitter and the second half-wave plate and is used for transmitting the output light of the second polarization beam splitter and filtering out backward pump light.

[0010] In the mode matching device based on spatial coupling, the input light incident side of the second dichroic mirror is provided with a signal light anti-reflection film, and the output side is provided with a signal light high-pass film; the signal light high-pass film is used for filtering out the backward pump light and transmitting the signal light in the input light.

[0011] In the mode matching device based on spatial coupling, the optical signal adjusting assembly further comprises a first polarization beam splitter; the first polarization beam splitter is arranged on the input side of the first half-wave plate and is used for filtering out non-horizontal polarization light in the input light.

[0012] In the mode matching device based on spatial coupling, the optical signal adjusting assembly further comprises a packaging shell; the first half-wave plate, the Faraday rotator, the second polarization beam splitter and the second half-wave plate are installed inside the packaging shell, and the packaging shell is provided with an input light port and an output light port; the input light port is installed in butt joint with the output side of the first optical fiber fixing part; and the output light port is installed in butt joint with the input side of the second optical fiber fixing part.

[0013] In the spatial coupling based mode matching device, the incident side of the input light of the first dichroic mirror is provided with a signal light high-pass film for signal light transmission and pump light reflection, and the exit side is provided with a signal light anti-reflection film.

[0014] In the spatial coupling based mode matching device, the first fiber fixing member comprises a first mounting base, a concave lens and a first lens; the first mounting base is mounted on the input side of the packaging module and has a first mounting channel penetrating through both sides; one end of the first mounting channel is used for mounting the end of the first fiber, and the other end is connected to the packaging module, and the concave lens and the first lens are sequentially arranged along the propagation direction of the input light; the concave lens is provided with a light transmission hole, and the signal light in the input light can be transmitted through the light transmission hole, and the pump light is scattered through the concave lens.

[0015] In the spatial coupling based mode matching device, the first mounting base comprises a first base, a first universal seat, a first elastic washer, a first bolt and a first set screw; the first elastic washer is clamped between the first base and the first universal seat; the first base is mounted on the input side of the packaging module, and the surface of the first base facing the first universal seat is provided with a first protrusion; the first universal seat is connected with the first base through the first bolt, and the first universal seat is mounted with the end of the first fiber, the concave lens and the first lens; one end of the first set screw penetrates through the first universal seat and abuts against the first protrusion to adjust the orientation of the output end of the first fiber.

[0016] In the spatial coupling based mode matching device, the first protrusion is in tangential contact with the end of the first set screw.

[0017] In the spatial coupling based mode matching device, the first mounting base further comprises a first fiber clamp and a first fixing screw; one end of the first fiber clamp is located in the first mounting channel, and the first fiber clamp has a first fiber mounting channel penetrating through both sides; the first fiber mounting channel is used for detachably mounting the first fiber, and the end located in the first mounting channel has a first accommodating portion accommodating the end cap of the first fiber; one end of the first fixing screw penetrates through the side wall of the first mounting base and abuts against the first fiber clamp to fix the position of the first fiber clamp.

[0018] In the spatial coupling-based mode matching device, the second fiber fixing member comprises a second mounting seat and a second lens; the second mounting seat is mounted on the input side of the packaging module and has a second mounting channel penetrating through two sides; one end of the second mounting channel is used for mounting the end of the second fiber, and the other end is connected to the packaging module and is provided with the second lens; the second lens is used for focusing the output light of the packaging module and inputting the second fiber.

[0019] In the spatial coupling-based mode matching device, the second mounting seat comprises a second base, a second gimbal, a second elastic washer, a second bolt and a second set screw; the second elastic washer is clamped between the second base and the second gimbal; the second base is mounted on the input side of the packaging module and is provided with a second protrusion on the surface facing the second gimbal; the second gimbal is connected to the second base through the second bolt, and the second gimbal is mounted with the end of the second fiber and the second lens; one end of the second set screw penetrates through the second gimbal and abuts against the second protrusion to adjust the orientation of the output end of the second fiber.

[0020] In the spatial coupling-based mode matching device, the second protrusion is in tangential contact with the end of the second set screw.

[0021] In the spatial coupling-based mode matching device, the second mounting seat further comprises a second fiber clamp and a second fixing screw; one end of the second fiber clamp is located in the second mounting channel and has a second fiber mounting channel penetrating through two sides; the second fiber mounting channel is used for detachably mounting the second fiber, and the end located in the second mounting channel has a second accommodating portion accommodating the end cap of the second fiber; one end of the second fixing screw penetrates through the side wall of the second mounting seat and abuts against the second fiber clamp to fix the position of the second fiber clamp.

[0022] The technical scheme adopted by the present application can achieve the following beneficial effects:

[0023] The present application mainly provides a spatial coupling-based mode matching device, which avoids the nonlinear phase shift caused by the excessively long non-radiating fiber in a spatial coupling manner and can meet the high-fidelity transmission of high-power and high-energy laser; avoids the mode mismatch and energy loss caused by the traditional fusion method, has a simple structure and is not easy to introduce additional loss; the first dichroic mirror is used to filter out the pump light, reduces the system thermal influence and improves the system stability; the photonic crystal fiber can be used for transmission to further improve the damage threshold. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments description will be briefly introduced as follows, which form a part of the present application. The schematic embodiments of the present application and the description and explanation thereof do not constitute an improper limitation on the present application. In the drawings:

[0025] Figure 1 It is a perspective view of a mode matching device based on spatial coupling according to the present application;

[0026] Figure 2 It is a front view of a mode matching device based on spatial coupling according to the present application;

[0027] Figure 3 It is a sectional view of the Z-Z direction of a mode matching device based on spatial coupling according to the present application; Figure 2

[0028] Figure 4 It is a sectional view of a first optical fiber fixing member according to the present application;

[0029] Figure 5 It is a perspective exploded view of a first optical fiber fixing member according to the present application;

[0030] Figure 6 It is a partial enlarged view of D of a mode matching device based on spatial coupling according to the present application; Figure 2

[0031] Figure 7 It is a sectional view of a second optical fiber fixing member according to the present application;

[0032] Figure 8 It is a perspective exploded view of a second optical fiber fixing member according to the present application;

[0033] Figure 9 It is a partial enlarged view of E of a mode matching device based on spatial coupling according to the present application; Figure 2

[0034] Figure 10 It is a working structure view of a mode matching device based on spatial coupling according to the present application.

[0035] Explanation of reference signs:

[0036] ​​​1. first fiber fixing part; 11. first mounting seat; 111. first mounting channel; 112. first base; 113. first gimbal; 114. first elastic washer; 115. first bolt; 116. first set screw; 117. first protrusion; 118. first snap ring; 12. concave lens; 121. light transmission hole; 13. first lens; 14. first fiber clamp; 141. first fiber mounting channel; 142. first accommodating part; 15. first fixing screw; 2. packaging module; 21. first dichroic mirror; 22. optical signal adjusting assembly; 221. first half-wave plate; 222. Faraday rotator; 223. second polarization beam splitter; 224. second half-wave plate; 225. second dichroic mirror; 226. first polarization beam splitter; 227. packaging shell; 2271. light inlet; 2272. light outlet; 2273. opening; 2274. cover; 3. second fiber fixing part; 31. second mounting seat; 311. second mounting channel; 312. second base; 313. second gimbal; 314. second elastic washer; 315. second bolt; 316. second set screw; 317. second protrusion; 318. second snap ring; 32. second lens; 33. second fiber clamp; 331. second fiber mounting channel; 332. second accommodating part; 34. second fixing screw; A. first optical fiber; B. second optical fiber; C. optical fiber amplifier; S1. pump light; S2. first non-horizontal polarized light; R1. backward pump light; R2. second non-horizontal polarized light; R3. backward harmful signal light. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below with specific embodiments of the present application and corresponding drawings. In the description of the present application, it should be noted that the term "or" is generally used in the sense of including "and / or" unless the context clearly indicates otherwise.

[0038] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection" and "connecting" should be understood broadly, for example, can be fixed connection, can be detachable connection, or integrally connected; can be mechanical connection, or magnetic connection; can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, the terms "first", "second" and the like are only used for distinguishing description, and cannot be understood as indicating or implying relative importance. In the description of the present application, the meaning of "multiple" is at least two, for example, two, three or more, etc., unless otherwise explicitly specified and limited.

[0039] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0040] To address the problems existing in the prior art, this application provides a pattern matching device based on spatial coupling.

[0041] like Figures 1-3 As shown, a pattern matching device based on spatial coupling includes a first fiber optic fixing component 1, an encapsulation module 2, and a second fiber optic fixing component 3. The first fiber optic fixing component 1 is installed on the input side of the encapsulation module 2 and is used to install the first fiber A and adjust the input light before inputting it into the encapsulation module 2. The second fiber optic fixing component 3 is installed on the output side of the encapsulation module 2 and is used to install the second fiber B and adjust the output light of the encapsulation module 2 before inputting it into the second fiber B. The encapsulation module 2 includes a first dichroic mirror 21 and an optical signal adjustment component 22 arranged sequentially along the light propagation direction. The first dichroic mirror 21 is used to filter out the pump light S1 in the input light. The optical signal adjustment component 22 is used to adjust the output light of the first dichroic mirror 21 to meet the input requirements of the fiber amplifier C before outputting it.

[0042] This invention provides a spatial coupling-based mode matching device. It achieves spatial coupling through the cooperation of a first fiber optic fixing component 1, an encapsulation module 2, and a second fiber optic fixing component 3. This avoids the nonlinear phase shift caused by excessively long unwired optical fibers and can meet the high-fidelity transmission requirements of high-power, high-energy lasers. It avoids mode mismatch and energy loss caused by traditional fusion splicing methods, has a simple structure, and is less prone to introducing additional losses. A first dichroic mirror filters out the pump light S1, reducing the system's thermal impact and improving system stability. Furthermore, it allows the use of photonic crystal fibers for transmission, further increasing the damage threshold.

[0043] In some preferred embodiments, a high-pass film for signal light is provided on the incident side of the input light of the first dichroic mirror 21 for signal light transmission and pump light S1 reflection, and an anti-reflection film for signal light is provided on the output side.

[0044] In some preferred embodiments, such as Figure 3 and Figure 10As shown, the optical signal adjusting assembly 22 comprises a first half-wave plate 221, a Faraday rotator 222, a second polarizing beam splitter 223 and a second half-wave plate 224 arranged in sequence along the light propagation direction; the first half-wave plate 221 and the Faraday rotator 222 are used to adjust the input light into horizontal polarized light; the second polarizing beam splitter 223 is used to transmit the horizontal polarized light in the light output by the Faraday rotator 222 into the second half-wave plate 224; the second half-wave plate 224 is used to adjust the polarization direction of the horizontal polarized light to meet the requirements of the input of the fiber amplifier C and then output; based on the first half-wave plate 221 and the Faraday rotator 222 used to adjust the input light into horizontal polarized light, the transmittance can be improved, and the second non-horizontal polarized light R2 in the backward harmful signal light R3 can be filtered out by the second polarizing beam splitter 223, so as to prevent the backward harmful signal light from returning to the previous amplifier, causing system instability or damage; specifically, the second polarizing beam splitter 223 is a Brewster angle thin film polarizing beam splitter.

[0045] In some preferred embodiments, as shown in Figure 3 and Figure 10 As shown, the optical signal adjusting assembly 22 further comprises a second dichroic mirror 225; the second dichroic mirror 225 is arranged on the light path between the second polarizing beam splitter 223 and the second half-wave plate 224, and is used to transmit the light output by the second polarizing beam splitter 223 and filter out the backward pumping light R1; based on the arrangement of the second dichroic mirror 225, the backward pumping light R1 in the backward harmful signal light R3 generated when the backward pumping amplifier is used can be filtered out, so as to avoid the thermal influence on the system and avoid the use of a traditional pump stripping device; when a large-core optical fiber is used in the pump stripping device, high-order modes are generated, the mode quality of the optical signal and the time-domain contrast of the optical pulse are reduced, and the system complexity and unreliability are increased.

[0046] Preferably, a signal light anti-reflection film is arranged on the input light incident side of the second dichroic mirror 225, used for transmitting the signal light in the input light; and a signal light high-pass film is arranged on the exit side, used for filtering out the backward pumping light R1 in the backward harmful signal light R3 and transmitting the signal light in the input light.

[0047] In some preferred embodiments, as shown in Figure 3 and Figure 10 As shown, the optical signal adjusting assembly 22 further comprises a first polarizing beam splitter 226; the first polarizing beam splitter 226 is arranged on the input side of the first half-wave plate 221, and is used to filter out the first non-horizontal polarized light S2 in the input light; in this way, the polarization extinction ratio of the optical signal is improved, and the backward harmful signal light R3 can be reflected and filtered out; preferably, the first polarizing beam splitter 226 is a Brewster angle thin film polarizing beam splitter.

[0048] In some preferred embodiments, as shown in Figure 1As shown, the optical signal adjusting assembly 22 further comprises a packaging shell 227; the first half-wave plate 221, the Faraday rotator 222, the second polarization beam splitter 223 and the second half-wave plate 224 are mounted inside the packaging shell 227, and the packaging shell 227 is provided with an input light port 2271 and an output light port 2272; the input light port 2271 is in butt joint with the output side of the first optical fiber fixing member 1; the output light port 2272 is in butt joint with the input side of the second optical fiber fixing member 3; and the opening 2273 and the cover 2274 are provided on the reflected light path of the second polarization beam splitter 223 to output the non-horizontal polarized light in the reflected backward harmful signal light R3.

[0049] In some preferred embodiments, the first optical fiber fixing member 1 comprises a first mounting seat 11, a concave lens 12 and a first lens 13; the first mounting seat 11 is mounted on the input side of the packaging module 2 and has a first mounting channel 111 penetrating through both sides; one end of the first mounting channel 111 is used for mounting the end of the first optical fiber A, and the other end is communicated with the packaging module 2, and the concave lens 12 and the first lens 13 are sequentially arranged along the input light propagation direction; the concave lens 12 is provided with a light transmission hole 121, and the signal light in the input light can be transmitted through the light transmission hole 121, and the pump light S1 is scattered through the concave lens 12; the concave surface of the concave lens 12 faces the output side, and based on scattering and filtering the pump light S1 in the input light with the concave lens 12 with the light transmission hole 121, the signal light is transmitted, which can reduce the thermal influence of the pump light S1 on the system, improve the stability, and does not affect the transmission of the signal light. For example, the first mounting channel 111 is arranged along the axis of the first mounting seat 11, thereby reducing the bending and joint of the optical fiber and reducing the transmission loss.

[0050] Preferably, as shown, Figures 4-6 The first mounting seat 11 comprises a first base 112, a first universal seat 113, a first elastic gasket 114, a first bolt 115 and a first set screw 116; the first elastic gasket 114 is clamped between the first base 112 and the first universal seat 113, and is preferably in sealing connection with both; the first base 112 is mounted on the input side of the packaging module 2 and the surface facing the first universal seat 113 is provided with a first protrusion 117; the first universal seat 113 is connected with the first base 112 through the first bolt 115, and the first universal seat 113 mounts the end of the first optical fiber A, the concave lens 12 and the first lens 13; one end of the first set screw 116 penetrates through the first universal seat 113 and abuts against the first protrusion 117 to adjust the orientation of the output end of the first optical fiber A; based on the cooperation of the first elastic gasket 114, the first set screw 116 and the first protrusion 117 between the first universal seat 113 and the first base 112 to realize the orientation adjustment of the output end of the first optical fiber A, the coupling efficiency is provided, and the insertion loss is further reduced, so that the insertion loss is less than 0.7 dB, and the insertion loss of commonly used MFA (mode field adapter) is about 1 dB.

[0051] Further preferably, the first bolt 115 is in a plurality, such as 2, 3, 4, etc., to improve the stability of the installation; the first top screw 116 and the first protrusion 117 are one-to-one corresponding and are in a plurality, such as 2, 3, 4, etc., to achieve multi-directional adjustment, further improve the coupling efficiency, and can reach 95%; preferably, the first bolt 115, the first top screw 116 and the first protrusion 117 are all three, alternately arranged, and arrayed along the first optical fiber A optical path as the axis; such as the first base 112, the first universal seat 113 butt joint is a flange pair structure, and the first bolt 115, the first top screw 116 and the first protrusion 117 are arranged on the flange respectively.

[0052] Further preferably, the first protrusion 117 is in tangential contact with the end of the first top screw 116; thereby, avoiding large-area contact to cause radial displacement of the first protrusion 117 and the first top screw 116, and even causing the first optical fiber A to generate radial position, reducing the coupling efficiency. Preferably, the surface of the first protrusion 117 in contact with the end of the first top screw 116 is an arc surface.

[0053] In some preferred embodiments, the concave lens 12 and the first lens 13 are respectively installed in the first mounting channel 111 through the first clasp ring 118, such as the first clasp ring 118 is screwed on the inner wall of the first clasp ring 118, and the concave lens 12 or the first lens 13 can be clamped and fixed by arranging two first clasp rings 118; the concave lens 12 can also be abutted on the step surface of the first mounting channel 111 through the first clasp ring 118.

[0054] In some preferred embodiments, the first mounting seat 11 further comprises a first optical fiber clamp 14 and a first fixing screw 15; one end of the first optical fiber clamp 14 is located in the first mounting channel 111, preferably in a clearance fit; and has a first optical fiber mounting channel 141 penetrating through both sides; the first optical fiber mounting channel 141 is used for detachably mounting the first optical fiber A, and the end located in the first mounting channel 111 has a first accommodating portion 142 accommodating the end cap of the first optical fiber A; one end of the first fixing screw 15 passes through the side wall of the first mounting seat 11 and abuts against the first optical fiber clamp 14 to fix the position of the first optical fiber clamp 14; based on mounting the first optical fiber A on the first optical fiber clamp 14 and detachable between the first optical fiber clamp 14 and the first mounting seat 11, it is convenient to replace the optical fiber; in the manner of accommodating the optical fiber end cap by the first accommodating portion 142, it can be applied to different specifications of optical fibers, improving the application range and compatibility; for example, the same specification end cap is adopted, preferably, the end cap can be selected as an SMA905 connector to have a higher damage threshold.

[0055] In some preferred embodiments, such as Figures 7-9As shown, the second fiber fixing member 3 comprises a second mounting seat 31 and a second lens 32; the second mounting seat 31 is mounted on the input side of the packaging module 2 and has a second mounting channel 311 through both sides; one end of the second mounting channel 311 is used for mounting the end of the second optical fiber B, and the other end is connected to the packaging module 2 and is provided with the second lens 32; the second lens 32 is used for focusing the output light of the packaging module 2 and inputting the second optical fiber B.

[0056] Preferably, the second mounting seat 31 comprises a second base 312, a second universal seat 313, a second elastic washer 314, a second bolt 315 and a second set screw 316; the second elastic washer 314 is clamped between the second base 312 and the second universal seat 313, and is preferably in sealing connection with both; the second base 312 is mounted on the input side of the packaging module 2 and the surface facing the second universal seat 313 is provided with a second protrusion 317; the second universal seat 313 is connected to the second base 312 by the second bolt 315, and the second universal seat 313 mounts the end of the second optical fiber B and the second lens 32; one end of the second set screw 316 passes through the second universal seat 313 and abuts against the second protrusion 317 to adjust the orientation of the output end of the second optical fiber B; based on the fact that the orientation of the output end of the second optical fiber B can be changed, the coupling efficiency can be improved, especially when the orientation of the end of the first optical fiber A can also be changed, the coupling efficiency can be further improved and the energy loss can be reduced.

[0057] Further preferably, the number of second bolts 315 is multiple, such as 2, 3, 4, etc., to improve the stability of installation; the second set screw 316 and the second protrusion 317 correspond to each other and are both multiple, such as 2, 3, 4, etc., to realize multi-directional adjustment and further improve the coupling efficiency to 95%; preferably, the number of second bolts 315, second set screws 316 and second protrusions 317 is three, which are alternately arranged and arrayed along the optical path of the second optical fiber A; for example, the joint of the second base 312 and the second universal seat 313 is a flange pair structure, and the second bolt 315, the second set screw 316 and the second protrusion 317 are arranged on the flanges, respectively.

[0058] Further preferably, the second protrusion 317 is in tangential contact with the end of the second set screw 316; in this way, the radial displacement of the second protrusion 317 and the second set screw 316 caused by large-area contact is avoided, and even the radial position of the second optical fiber A is avoided, thereby reducing the coupling efficiency. Preferably, the surface of the second protrusion 317 in contact with the end of the second set screw 316 is an arc surface. Preferably, the surface of the second protrusion 317 in contact with the end of the second set screw 316 is an arc surface.

[0059] In some preferred embodiments, the second lens 32 is mounted in the second mounting channel 311 by the second clamping ring 318, such as the second clamping ring 318 is screwed to the inner wall of the second clamping ring 318, and the second lens 32 is pressed against the stepped surface of the second mounting channel 311 by the second clamping ring 318.

[0060] In some preferred embodiments, as shown in Figure 7 and Figure 8 As shown in the second mounting seat 31 also includes a second fiber clamp 33 and a second fixing screw 34; one end of the second fiber clamp 33 is located in the second mounting channel 311, preferably in a clearance fit; and has a second fiber mounting channel 331 through both sides; the second fiber mounting channel 331 is used for detachably mounting the second fiber B, and the end located in the second mounting channel 311 has a second accommodating portion 332 accommodating the end cap of the second fiber A; one end of the second fixing screw 34 passes through the side wall of the second mounting seat 31 and abuts against the second fiber clamp 33 to fix the position of the second fiber clamp 33. Based on the installation of the second fiber A on the second fiber clamp 33, and the detachability between the second fiber clamp 33 and the second mounting seat 31, it is convenient to replace the fiber, and the way of accommodating the fiber end cap by the second accommodating portion 332 can be applied to different specifications of fibers, improving the application range and compatibility; for example, the same specification end cap is adopted, preferably, the end cap can be selected as an SMA905 connector to have a higher damage threshold.

[0061] The working process of the device of the present application is described as follows:

[0062] The input light is collimated by the first lens 13 and enters the first dichroic mirror 21, the first dichroic mirror 21 reflects the pump light S1 in the input light, the signal light is transmitted into the first polarization beam splitter 226, the first polarization beam splitter 226 filters out the first non-horizontal polarized light S2 in the input light and enters the first polarizer 221 and the Faraday rotator 222, the polarization direction is rotated to horizontal polarization after passing through the two, and then enters the second polarization beam splitter 223, the second polarization beam splitter 223 filters out the vertical polarized light in the input light, the horizontal polarized light is transmitted into the second dichroic mirror 225, and then the polarization direction is rotated to meet the second polarizer 224, and then focused into the second fiber B by the second lens 32 and finally enters the backward pumping amplifier C;

[0063] The backward harmful light generated by the backward pumping amplifier C is collimated by the second lens 32 and enters the second dichroic mirror 225 after passing through the second polarizer 224, the second dichroic mirror 225 filters out the backward pumping light R1; then enters the second polarizing beam splitter 223, the second polarizing beam splitter 223 filters out the second non-horizontal polarized light R2 in the backward harmful light, the horizontal polarized light rotates the polarization direction through the Faraday rotator 222 and the first polarizer 221, forms the vertical polarized light, and the vertical polarized light is reflected and eliminated by the first polarizing beam splitter 226.

[0064] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative but not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, which all belong to the protection of the present application.

Claims

1. A pattern matching device based on spatial coupling, characterized in that, Includes a first fiber optic fixing component, an encapsulation module, and a second fiber optic fixing component; The first optical fiber fixing component is installed on the input side of the encapsulation module and is used to install the first optical fiber and to input the input light into the encapsulation module after adjustment; The second optical fiber fixing component is installed on the output side of the encapsulation module, used to install the second optical fiber, and to input the output light of the encapsulation module into the second optical fiber after adjustment; The encapsulation module includes a first dichroic mirror and an optical signal adjustment component arranged sequentially along the light propagation direction; The first dichroic mirror is used to filter out the pump light in the input light; The optical signal adjustment component is used to adjust the output light of the first dichroic mirror to meet the input requirements of the fiber optic amplifier before outputting it. The first optical fiber fixing component includes a first mounting base, a concave lens, and a first lens; The first mounting base is installed on the input side of the packaging module and has a first mounting channel that runs through both sides; One end of the first mounting channel is used to mount the end of the first optical fiber, and the other end is connected to the encapsulation module. The concave lens and the first lens are arranged sequentially along the direction of the input light propagation. The concave lens is provided with a light-transmitting hole, through which the signal light in the input light can be transmitted and the pump light is scattered by the concave lens; The first mounting base includes a first base, a first universal joint, a first elastic washer, a first bolt, and a first set screw; The first elastic washer is sandwiched between the first base and the first universal joint; The first base is mounted on the input side of the packaging module, and a first protrusion is provided on the surface facing the first universal joint; The first universal joint is connected to the first base by the first bolt, and the first universal joint is used to mount the end of the first optical fiber, the concave lens, and the first lens; One end of the first set wire passes through the first universal joint and abuts against the first protrusion to adjust the orientation of the first optical fiber output end.

2. The pattern matching device based on spatial coupling according to claim 1, characterized in that, The optical signal adjustment component includes a first half-wave plate, a Faraday rotator, a second polarizing beam splitter, and a second half-wave plate arranged sequentially along the light propagation direction. The first half-wave plate and the Faraday rotator are used to adjust the input light into horizontally polarized light; The second polarizing beam splitter is used to transmit the horizontally polarized light in the output light of the Faraday rotator into the second half-wave plate; The second half-wave plate is used to adjust the polarization direction of the horizontally polarized light to meet the input requirements of the fiber amplifier before outputting it.

3. The pattern matching device based on spatial coupling according to claim 2, characterized in that, The optical signal adjustment component also includes a second dichroic mirror; The second dichroic mirror is disposed in the optical path between the second polarizing beam splitter and the second half-wave plate, and is used to transmit the output light of the second polarizing beam splitter and filter out the back pump light.

4. The pattern matching device based on spatial coupling according to claim 3, characterized in that, The second dichroic mirror has a signal light anti-reflection film on the input light incident side and a signal light high-pass film on the output side. The high-pass filter for signal light is used to filter out the backpump light and transmit the signal light in the input light.

5. The pattern matching device based on spatial coupling according to claim 2, characterized in that, The optical signal adjustment component also includes a first polarizing beam splitter; The first polarizing beam splitter is disposed on the input side of the first half-wave plate and is used to filter out non-horizontally polarized light in the input light.

6. The pattern matching device based on spatial coupling according to claim 2, characterized in that, The optical signal adjustment component also includes a packaging housing; The first half-wave plate, Faraday rotator, second polarizing beam splitter, and second half-wave plate are installed inside the encapsulation housing, and the encapsulation housing is provided with an inlet and an outlet. The light inlet is connected to the light outlet side of the first optical fiber fixing component; The light outlet is connected to the light input side of the second optical fiber fixing component.

7. The pattern matching device based on spatial coupling according to claim 1, characterized in that, The first dichroic mirror has a signal light high-pass film on the incident side of the input light for signal light transmission and pump light reflection, and a signal light anti-reflection film on the output side.

8. The pattern matching device based on spatial coupling according to claim 1, characterized in that, The first protrusion is in tangential contact with the end of the first set screw.

9. The pattern matching device based on spatial coupling according to claim 1, characterized in that, The first mounting base also includes a first optical fiber clamp and a first fixing screw; One end of the first optical fiber clamp is located within the first mounting channel, and it has a first optical fiber mounting channel that extends through both sides. The first optical fiber mounting channel is used to detachably mount the first optical fiber, and the end located within the first mounting channel has a first receiving portion for accommodating an end cap of the first optical fiber; One end of the first fixing screw passes through the side wall of the first mounting base and abuts against the first optical fiber clamp to fix the position of the first optical fiber clamp.

10. The pattern matching device based on spatial coupling according to claim 1, characterized in that, The second fiber optic fixing component includes a second mounting base and a second lens; The second mounting base is installed on the input side of the packaging module and has a second mounting channel that runs through both sides; One end of the second mounting channel is used to mount the end of the second optical fiber, and the other end is connected to the encapsulation module and is provided with the second lens; The second lens is used to focus the output light of the encapsulation module and input it into the second optical fiber.

11. The pattern matching device based on spatial coupling according to claim 10, characterized in that, The second mounting bracket includes a second base, a second universal joint, a second elastic washer, a second bolt, and a second set screw; The second elastic washer is sandwiched between the second base and the second universal joint; The second base is mounted on the input side of the packaging module, and a second protrusion is provided on the surface facing the second universal joint; The second universal joint is connected to the second base by the second bolt, and the end of the second optical fiber and the second lens are mounted on the second universal joint. One end of the second set wire passes through the second universal joint and abuts against the second protrusion to adjust the orientation of the second optical fiber output end.

12. The pattern matching device based on spatial coupling according to claim 11, characterized in that, The second protrusion is in tangential contact with the end of the second set screw.

13. The pattern matching device based on spatial coupling according to claim 10, characterized in that, The second mounting base also includes a second fiber optic clamp and a second fixing screw; One end of the second fiber clamp is located within the second mounting channel, and it has a second fiber mounting channel that extends through both sides; The second fiber mounting channel is used for detachably mounting the second fiber, and the end located within the second mounting channel has a second receiving portion for accommodating an end cap of the second fiber; One end of the second fixing screw passes through the side wall of the second mounting base and abuts against the second optical fiber clamp to fix the position of the second optical fiber clamp.

Images