Optical fiber clamp and optical fiber laser

Abstract

The utility model discloses an optical fiber clamp (1), which is provided with an arc-shaped bent clamping part (1A) suitable for clamping an optical fiber, and the bent clamping part (1A) is configured to be suitable for being used as a long-period grating together with the clamped optical fiber by keeping the clamped optical fiber in a preset composite bent shape. The utility model also provides an optical fiber laser (100), which comprises an indication light module (20), a resonant cavity module (40) and a reverse light isolation module (30), is arranged between the indication light module (20) and the resonant cavity module (40), and comprises a long-period grating assembly (31) and a cladding light filter (32), and the long-period grating assembly (31) is composed of at least one optical fiber clamp (1) and a clamped optical fiber. According to certain exemplary embodiments, a desired long-period grating can be provided only by clamping an optical fiber with an optical fiber clamp, undesired light transmitted reversely is further filtered out, the returned light is prevented from damaging an indication light source and the optical fiber, and the SRS effect of the system is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of optical fiber lasers, in particular to an optical fiber clamp and an optical fiber laser comprising the optical fiber clamp. Background Art

[0002] A typical fiber laser usually includes an indicator light path, multiple pump sources, a resonant cavity, and a beam combiner that couples the indicator light of the indicator light path and the pump light of multiple pump sources into the resonant cavity. The resonant cavity usually includes a high-reflection Bragg grating, a gain fiber, and a low-reflection Bragg grating. Due to the incomplete reflection of the high-reflection Bragg grating in the resonant cavity, the signal light generated in the resonant cavity, the unabsorbed residual pump light, and / or the Raman light generated by the entire oscillation system may pass through the high-reflection Bragg grating and be transmitted back through the fiber core to the indicator light path. For example, for a 3kW fiber laser, the power of such reverse transmission light may be as high as 100W or more, which will cause damage to the optical fiber, the indicator light source, and even the entire oscillation system, seriously affecting the reliability and stability of the fiber laser.

[0003] In response to the above-mentioned problem of reverse transmission of light, a commonly used solution is to add multiple turns of wound optical fiber and cladding light filter between the indicator light path and the resonant cavity to remove the reverse transmission light. However, such a winding structure has limited effect on eliminating reverse transmission light. After passing through the winding structure, there is often still a large amount of reverse transmission light in the fiber core. There is also a solution of adding a long-period fiber grating between the indicator light path and the resonant cavity to remove the reverse transmission light from the fiber core. Such a long-period fiber grating is usually obtained by using CO2 ablation, ultraviolet lithography, electrode discharge, quasi-laser etching and other technical means. Obviously, this will increase the manufacturing complexity of the fiber laser and increase the cost. It can be seen that the existing technology still has a lot of room for improvement in eliminating reverse transmission light in fiber lasers. Utility Model Content

[0004] The purpose of the utility model is to provide an optical fiber clamp and an improved optical fiber laser having the optical fiber clamp, which can at least partially solve the problems existing in the prior art.

[0005] According to a first aspect of the utility model, a fiber clamp is provided, which has an arc-shaped curved clamping portion suitable for clamping an optical fiber, and the curved clamping portion is configured to be suitable for use as a long-period grating together with the clamped optical fiber by maintaining the clamped optical fiber in a predetermined complex curved shape.

[0006] According to an optional embodiment, the curved clamping portion comprises at least one corrugated clamping section consisting of opposing corrugated clamping surfaces, the radius of curvature of each corrugated section of the at least one corrugated clamping section being dependent on a grating period for coupling light of a corresponding at least one target wavelength from the core of the clamped optical fiber to the cladding, wherein the radius of curvature satisfies the following relationship:

[0007] in θ is the center angle of the waveform segment, l z is the chord length corresponding to the waveform segment, and m is an integer greater than 1.

[0008] According to an optional embodiment, each of the corrugated clamping sections has at least three continuous corrugated sections.

[0009] According to an optional embodiment, a central angle of each wave segment of the at least one wave-shaped clamping section is less than 90 degrees.

[0010] According to an optional embodiment, the optical fiber clamp has a first clamping block and a second clamping block, the first clamping block has a corrugated first clamping surface, the second clamping block has a corrugated second clamping surface that is opposite to the first corrugated clamping surface and has a matching shape, and the first clamping block is configured to be movable and fixed between a first position where the first clamping surface and the second clamping surface are in surface contact with each other relative to the second clamping block and a second position where the first clamping surface and the second clamping surface are separated by a predetermined distance.

[0011] According to an optional embodiment, the periphery of the first clamping block includes an arc-shaped first segment and an arc-shaped second segment which are circumferentially continuous with each other, the first segment serves as the first clamping surface, and the second segment serves as a curved winding surface of the curved winding portion.

[0012] According to an optional embodiment, the curved clamping portion is formed as a minor arc shape as a whole, and the curved winding portion is formed as a major arc shape.

[0013] According to an optional embodiment, the second clamping block includes a boss portion and a bearing portion, the bearing portion forms a bearing plane for bearing the first clamping block, the boss portion protrudes from the bearing plane and forms the second clamping surface, and the first clamping block is configured to be suitable for sliding and fixing along the bearing plane close to and away from the second clamping surface.

[0014] According to an optional embodiment, the optical fiber clamp further comprises an arc-shaped curved winding portion suitable for winding the non-clamped portion of the clamped optical fiber therearound.

[0015] According to an optional embodiment, the radius of curvature of the curved winding portion depends on the tensile strength of the clamped optical fiber.

[0016] According to an optional embodiment, the diameter of the curved winding portion is more than 200 times the diameter of the clamped optical fiber.

[0017] According to an optional embodiment, the optical fiber clamp further comprises a position locking mechanism adapted to lock and release the first clamping block relative to the second clamping block.

[0018] According to the second aspect of the utility model, a fiber laser is provided, which includes: an indicator light module; a resonant cavity module; and a reverse light isolation module, which is arranged between the indicator light module and the resonant cavity module, and includes a long-period grating component and a cladding light filter composed of at least one fiber clamp according to the first aspect of the utility model and a clamped optical fiber.

[0019] According to an optional embodiment, the laser light from the indicator light module is input into the reverse light isolation module from the cladding light filter side, and is input into the resonant cavity module after passing through the reverse light isolation module.

[0020] According to an optional embodiment, the long period grating component is configured to couple the reversely transmitted core laser from the resonant cavity module to the cladding, and the cladding light filter is adapted to eliminate the laser coupled to the cladding.

[0021] According to an optional embodiment, the curved clamping portion of at least one optical fiber clamp of the long-period grating assembly includes a first wavy clamping segment, and the first wavy clamping segment and its corresponding clamped optical fiber segment are configured to be suitable for coupling reverse-transmitted signal light from the resonant cavity module to the first long-period grating of the cladding.

[0022] According to an optional embodiment, the curved clamping portion of at least one optical fiber clamp of the long-period grating assembly further includes: a second wavy clamping section, wherein the second wavy clamping section and its corresponding clamped optical fiber section are configured to be suitable for coupling the reverse-transmitted Raman light from the resonant cavity module to the second long-period grating of the cladding; and / or a third wavy clamping section, wherein the third wavy clamping section and its corresponding clamped optical fiber section are configured to be suitable for coupling the reverse-transmitted pump light from the resonant cavity module to the third long-period grating of the cladding.

[0023] According to an optional embodiment, the clamped optical fiber is arranged to be coiled around a first clamping block of the optical fiber clamp having a circumferentially continuous first clamping surface and a curved winding surface for at least one circle and is clamped by a corresponding wavy clamping section of the curved clamping portion at the first clamping surface.

[0024] According to an optional embodiment, the fiber laser further includes a mode matcher disposed between the indicator light module and the reverse light isolation module.

[0025] According to an optional embodiment, the resonant cavity module includes a forward pump source, a forward combiner, a high-reflection Bragg grating, a gain fiber, a low-reflection Bragg grating, a reverse combiner, a reverse pump source, another cladding light filter and an output head, which are arranged in sequence along the forward output direction of the indicator light module.

[0026] According to certain exemplary embodiments of the utility model, a long-period grating can be provided at an appropriate position of the optical path of a fiber laser simply and conveniently by using a fiber clamp of simple construction. The long-period grating is suitable for filtering light in a larger wavelength range centered on a target wavelength from the core and coupling it to the cladding due to its complex curved shape. Preferably, a curved winding portion of the optical fiber is further provided to couple more light in the wavelength range from the core to the cladding simply by bending the optical fiber. This makes it possible to couple various components of light transmitted in the reverse direction from the core to the cladding as much as possible in the fiber laser, thereby helping to filter them out of the cladding, thereby isolating the reversely transmitted light, protecting the indicator light module, reducing the possibility of optical fiber fuse, and reducing the SRS (stimulated Raman scattering) effect of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be described in more detail below with reference to the accompanying drawings, so that the principles, features and advantages of the present invention can be better understood. The accompanying drawings include:

[0028] Figure 1A and 1B The plan views of the first clamping block and the second clamping block of the optical fiber clamp according to an exemplary embodiment of the utility model are respectively shown;

[0029] Figure 2 A plan view of an optical fiber clamp according to an exemplary embodiment of the present utility model is shown;

[0030] Figure 3 A perspective view of an optical fiber clamp according to an exemplary embodiment of the present utility model is shown;

[0031] Figure 4 A three-dimensional view of the optical fiber clamp according to an exemplary embodiment of the present utility model viewed from another angle is shown, wherein the first clamp block is separated from the second clamp block by a large distance;

[0032] Figure 5 A waveform section of a wavy clamping section of a curved clamping portion of an optical fiber clamp and its dimension parameters are schematically shown;

[0033] Figure 6A schematic diagram showing the main parts of a fiber laser according to an exemplary embodiment of the present invention; and

[0034] Figure 7 A schematic structural diagram of a fiber laser according to an exemplary embodiment of the utility model is shown. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the scope of protection of the present invention.

[0036] For the purpose of clear description, directional or orientation terms may be used in this article, but unless otherwise specified, any directional or orientation terms involved are relative to normal usage status, but this does not mean that this direction or orientation is the case in any scenario.

[0037] Figure 1A and 1B The plan views of the first clamping block 11 and the second clamping block 12 of the optical fiber clamp 1 according to an exemplary embodiment of the present utility model are respectively shown; Figure 2 A plan view of an optical fiber clamp 1 according to an exemplary embodiment of the present utility model is shown; Figure 3 A perspective view of an optical fiber clamp 1 according to an exemplary embodiment of the present utility model is shown; Figure 4 A three-dimensional view of the optical fiber clamp 1 according to an exemplary embodiment of the present utility model is shown from another angle, wherein the first clamping block 11 and the second clamping block 12 are separated by a large distance; Figure 5 A wave-shaped section of a wave-shaped clamping section of the curved clamping portion 1A of the optical fiber clamp 1 and its dimension parameters are schematically shown.

[0038] Before officially starting the description, it should be noted that due to the viewing angle and the space limitations of the figure marks in the figures, some figure marks are not marked in all views. Therefore, when referring to the description, if necessary, you can refer to multiple views at the same time to facilitate understanding, but this does not mean that all features must appear at the same time in all embodiments.

[0039] like Figures 1A to 5 As shown, a fiber clamp 1 according to an exemplary embodiment of the present invention comprises a first clamping block 11 and a second clamping block 12 , and a position locking mechanism 13 for locking and releasing the relative positions of the first clamping block 11 and the second clamping block 12 .

[0040] In an exemplary embodiment, Figure 1A , Figures 2 to 4 As shown, the first clamping block 11 is formed into a roughly circular plate shape with an axial dimension significantly smaller than a radial dimension, and its periphery includes a first section and a second section that are continuous with each other in the circumferential direction, the first section is formed into a wavy first clamping surface 111, and the second section can be formed into any appropriate shape. In a preferred embodiment, the second section can be formed into an arc-shaped curved winding surface 112, which will be described in detail later. The central area of ​​the first clamping block 11 is also formed with an axially penetrating positioning track 113, which is suitable for cooperating with the position locking mechanism 13 and the corresponding part of the second clamping block 12 to adjust and fix the position of the first clamping block 11 relative to the second clamping block 12.

[0041] In an exemplary embodiment, Figure 1B , Figures 2 to 4 As shown, the second clamping block 12 is also formed into a roughly circular plate shape with an axial dimension significantly smaller than the radial dimension, which includes a boss portion 12A and a bearing portion 12B. The bearing portion 12B is formed into a plate shape having a bearing plane 122. The boss portion 12A protrudes axially from the bearing plane 122 at a portion of the periphery of the bearing portion 12B, and the side of the boss portion 12A facing the bearing plane 122 is formed into a wavy second clamping surface 121, the shape of which matches the shape of the first clamping surface 111. A central area of ​​the bearing plane 122 corresponding to the central area of ​​the first clamping block 11 is formed with a positioning protrusion 123 protruding in the axial direction, and the positioning protrusion 123 can cooperate with the positioning track 113 of the first clamping block 11 to guide the movement of the first clamping block 11 on the bearing plane 122 of the second clamping block 12, wherein the positioning track 113 and the positioning protrusion 123 are configured to enable the first clamping block 11 to be in surface contact with the first clamping surface 111 and the second clamping surface 121 relative to the second clamping block 12 or to be in a first position ( Figure 2 and Figure 3 Schematically shown, for clarity, not shown in a fully fitted state) is separated from the first clamping surface 111 and the second clamping surface 121 by a predetermined distance ( Figure 4 The schematic diagram shows movement between an intermediate position separated by a predetermined distance, where the predetermined distance may be any appropriate distance determined by appropriate dimensions of the positioning track 113 and the positioning protrusion 123.

[0042] In an exemplary embodiment, Figure 1B , Figures 2 to 4As shown, the position locking mechanism 13 may include, for example, a bolt 131 shown in the figure and a threaded hole 132 provided on the positioning protrusion 123 of the second clamping block 12, wherein the bolt 131 is adapted to pass through the positioning track 113 of the first clamping block 11 and be screwed into the threaded hole 132, so that the first clamping block 11 can be clamped between the head of the bolt 131 and the bearing plane 122 of the second clamping block 12 when tightened, and the first clamping block 11 is allowed to slide between the head of the bolt 131 and the bearing plane 122 of the second clamping block 12 when not tightened. As shown in the figure, the head of the bolt 131 is formed with an ear piece 133 to facilitate the screwing operation. Of course, the position locking mechanism 13 may also be or include other structures, as long as it can achieve relative position adjustment and locking between the first clamping block 11 and the second clamping block 12.

[0043] The first clamping surface 111 of the first clamping block 11 and the second clamping surface 121 of the second clamping block 12 together constitute a curved clamping portion 1A suitable for clamping an optical fiber of the optical fiber clamp 1 according to an exemplary embodiment of the utility model, and the curved clamping portion 1A is configured to be suitable for forming a long-period grating together with the clamped optical fiber by maintaining the clamped optical fiber in a predetermined curved shape.

[0044] Specifically, the first clamping surface 111 and the second clamping surface 121 each include at least one matching corrugated clamping section, forming at least one corrugated clamping section corresponding to the curved clamping portion 1A, each corrugated clamping section may include at least three corrugated segments, and the radius of curvature of each corrugated segment depends on the grating period for coupling the corresponding target wavelength of light from the core of the clamped optical fiber to the cladding. Figure 5 As shown, R is the radius of curvature of the waveform segment, θ is the central angle of the waveform segment, preferably a value less than or equal to 90°, l z is the chord length corresponding to the waveform segment, Λ is the grating period of the light of the corresponding target wavelength coupled from the core of the clamped optical fiber to the cladding, m is an integer greater than 1, where R is determined so that the parameters of the waveform segment satisfy the following relationship:

[0045] in

[0046] The main dimensions of the wave segment, including the radius of curvature and the central angle, are determined thereby.

[0047] In the clamped optical fiber located at such a bent clamping portion 1A of the optical fiber clamp 1, light of a corresponding target wavelength can be coupled from the core into the cladding, while light of a non-target wavelength is not affected.

[0048] The curved clamping portion 1A of the optical fiber clamp 1 may include only one wavy clamping section of a single size, or may include more than one wavy clamping section of different sizes. Taking the application scenario in the optical fiber laser as an example, the optical fiber clamp 1 may have only one wavy clamping section for only one of the reversely transmitted signal light, residual pump light and Raman light, or may include two or three wavy clamping sections of different sizes to couple one or more of the reversely transmitted signal light, residual pump light and Raman light in the clamped optical fiber from the core to the cladding. Multiple wavy clamping sections may be continuous in the circumferential direction, which can be easily achieved by appropriately arranging multiple wave segments of different sizes.

[0049] As described above, in a preferred exemplary embodiment, the curved winding surface 112 as the second section of the first clamping block 11 constitutes the curved winding portion 1B of the optical fiber clamp 1 according to the exemplary embodiment of the utility model, which is suitable for winding the optical fiber. The light within the bandwidth including the target wavelength in the core of the optical fiber segment wound on the curved winding portion 1B will be greatly attenuated by simply bending the optical fiber, and the attenuation is inversely proportional to the bending diameter D of the curved winding surface 112. However, the smaller the bending diameter D is, the better. The tensile strength of the optical fiber itself must also be considered. According to experience, the bending diameter D of the curved winding surface 112 is selected to be more than 200 times the diameter of the clamped optical fiber. By using the additional curved winding portion 1B, the light of the target wavelength in the core can be greatly attenuated first outside the curved clamping portion 1A, thereby further improving the stripping efficiency of the light of the target wavelength in the core as a whole.

[0050] In one example of use, the optical fiber can be Figure 4 The first clamping block 11 shown is wound around the entire first clamping block 11 in a state where the first clamping block 11 is separated from the second clamping block 12 by a certain distance, and the winding starting point and winding end point are both located on the curved winding portion 1B and there may be a circumferentially overlapping optical fiber portion between the two according to the situation. Subsequently, the first clamping block 11 moves along its positioning track 113 toward the boss portion 12A of the second clamping block 12 until the optical fiber is clamped between the first clamping surface 111 and the second clamping surface 112, and then the position locking mechanism 13 is used to lock the position of the first clamping block 11 relative to the second clamping block 12, for example, by tightening the bolt 131, thereby completing the clamping of the optical fiber by the optical fiber clamp 1.

[0051] The optical fiber clamp according to the utility model is not limited to the above structure. For example, the optical fiber clamp may only have an optical fiber clamping portion without an optical fiber winding portion, that is, the optical fiber only passes through the curved clamping portion without additionally winding around the first clamping block 11. Alternatively, the optical fiber clamp may have an additional optical fiber winding portion, for example, it may be formed as a convex ring that further protrudes along the axial direction of the first clamping block 11 with a curved diameter D of the curved winding portion 1B. In addition to winding around the first section and the second section of the first clamping block 11 for one circle, the optical fiber can also be wound around the convex ring for a required number of circles without passing through the curved clamping portion. In addition, when the curved clamping portion has multiple wavy clamping sections, the multiple wavy clamping sections are not limited to being arranged in the circumferential direction. Some or all of them can also be arranged in the axial direction. At this time, the optical fiber needs to be wound around the first clamping block 11 for a corresponding number of circles, and each circle travels along an axially arranged section. For this purpose, flanges or grooves can also be provided on the two clamping surfaces as optical fiber tracks.

[0052] Figure 6 FIG. 1 is a schematic diagram showing main parts of a fiber laser 100 according to an exemplary embodiment of the present invention. Figure 7 FIG. 1 shows a schematic diagram of the structure of a fiber laser 100 according to an exemplary embodiment of the present utility model. Figure 6 and Figure 7 As shown, the utility model also relates to a fiber laser 100, which at least includes an indicator light module 20, a reverse light isolation module 30 and a resonant cavity module 40, wherein the reverse light isolation module 30 is arranged between the indicator light module 20 and the resonant cavity module 40, and includes a long-period grating component 31 and a cladding light filter 32 composed of at least one fiber clamp 1 according to an embodiment of the utility model and a clamped optical fiber.

[0053] The indicator light module 20 is, for example, an indicator red light laser, for example, emitting an indicator red light of 650 nm. The indicator light from the indicator light module 20 is input into the reverse light isolation module 30 from the cladding light filter 32 side, and is input into the resonant cavity module 40 after passing through the reverse light isolation module 30. The reversely transmitted core laser from the resonant cavity module 40 is input into the reverse light isolation module 30 from the long period grating component 31 side, is coupled from the core to the cladding in the long period grating component 31, and then is eliminated from the cladding by the cladding light filter 32, thereby preventing it from damaging the indicator light source and even the entire optical path system.

[0054] In an exemplary embodiment, the long-period grating component 31 may include only one fiber clamp 1, the curved clamping portion 1A of which has at least one wavy clamping section designed mainly for the wavelength of the signal light, so that the long-period grating component 31 includes at least one long-period grating configured to couple the reverse-transmitted signal light from the resonant cavity module 40 to the cladding, and such a long-period grating can usually also couple a considerable portion of the pump light and Raman light in the core that are relatively close to the wavelength of the signal light to the cladding, of course, the signal light is coupled to the cladding in the largest proportion. Therefore, in general, it is sufficient to use only one fiber clamp designed mainly for the signal light in the fiber laser. Of course, the fiber clamp 1 may also have two other wavy clamping sections designed mainly for the pump light and the Raman light, respectively, so that the long-period grating component 31 can additionally include two long-period gratings configured to couple the reverse-transmitted pump light and Raman light to the cladding, respectively. In this case, the clamped optical fiber is arranged to be wound around the first clamping block 11 of the optical fiber clamp 1 having a circumferentially continuous first clamping surface 111 and a curved winding surface 112 for at least one circle and is clamped by the corresponding wavy clamping section of the curved clamping portion 1A at the first clamping surface 111.

[0055] In other embodiments, the long-period grating assembly 31 may also include two or three fiber clamps 1 with different configurations of the curved clamping parts 1A (different numbers, size parameters and / or arrangements of the wavy clamping segments), or include more fiber clamps 1 as needed. As long as the multiple fiber clamps 1 as a whole include the required wavy clamping segments, mainly wavy clamping segments for signal light, so as to achieve coupling of light of each target wavelength to the corresponding long-period grating of the cladding, the specific number and configuration are not particularly limited.

[0056] In an exemplary embodiment, the resonant cavity module 40 includes a forward pump source 41, a forward beam combiner 42, a high reflection Bragg grating 43, a gain fiber 44, a low reflection Bragg grating 45, a reverse beam combiner 46, a reverse pump source 47, another cladding light filter 48 and an output head 49, which are sequentially arranged along the forward output direction of the indicator light module. The forward pump source 41 and the reverse pump source 47 are semiconductor lasers with fiber-coupled output, providing pump light with a wavelength of 976 nm, and the number of them is m1 and m2 respectively, and m1 and m2 may be equal or unequal, and the resonant cavity composed of the high reflection Bragg grating 43, the gain fiber 44 and the low reflection Bragg grating 45 is accessed from the side of the high reflection Bragg grating 43 and the side of the low reflection Bragg grating 45 through the forward beam combiner 42 and the reverse beam combiner 47 configured as (n+1)×1, respectively, and n is greater than the larger of m1 and m2, and the configuration of the two beam combiners may also be different as needed. The pump light of 976nm band is converted into the signal light of 1080nm band (Ytterbium-doped double-clad fiber) or 1550nm band (Erbium-doped double-clad fiber) through the gain fiber 44 in the resonant cavity. The signal light is highly reflected (reflectivity ≥ 99%) at the high-reflection Bragg grating 43 and low-reflected (reflectivity ≤ 10%) at the low-reflection Bragg grating 45 and output from the resonant cavity, and then output from the output head 49 after passing through another cladding light filter 48. Accordingly, the long-period grating component 31 of the reverse optical isolation module 30 is configured to couple the pump light of 976nm, the signal light of 1080nm or 1550nm and the corresponding Raman scattered light to the cladding through one or more fiber clamps 1 included therein, and then stripped from the cladding by the cladding light filter 32.

[0057] In an exemplary embodiment, the fiber laser 100 further includes a mode matcher 50 disposed between the indicator light module 20 and the reverse light isolation module 30 .

[0058] According to the various embodiments of the present invention, the desired long-period grating can be provided only by clamping the fiber clamp 1 according to the embodiment of the present invention at the appropriate position of the optical fiber of the fiber laser, thereby blocking and eliminating the undesired light transmitted in the reverse direction, protecting the indicator light source from being damaged by the returned light, reducing the possibility of optical fiber melting, and reducing the SRS effect of the system. In addition, since the fiber clamp 1 according to the present invention is a mechanical component with a stable structure, it can provide uniform, stable, reliable, and reproducible bending of the optical fiber, thereby providing a fiber laser 100 with more stable performance. Moreover, the fiber clamp 1 according to the present invention is easy to manufacture, install and apply, and has low cost.

[0059] Although specific embodiments of the present invention are described in detail herein, they are provided for the purpose of explanation only and should not be considered to limit the scope of the present invention. Various substitutions, changes and modifications may also be conceived without departing from the spirit and scope of the present invention.

Claims

1. An optical fiber clamp (1), characterized in that: The optical fiber clamp (1) has an arc-shaped curved clamping portion (1A) suitable for clamping an optical fiber, and the curved clamping portion (1A) is configured to be suitable for use as a long-period grating together with the clamped optical fiber by maintaining the clamped optical fiber in a predetermined complex curved shape, wherein The curved clamping portion (1A) comprises at least one wavy clamping section formed by opposing wavy clamping surfaces, wherein the radius of curvature (R) of each wavy segment of the at least one wavy clamping section depends on the grating period (Λ) for coupling the corresponding at least one target wavelength of light from the core of the clamped optical fiber to the cladding.

2. The optical fiber clamp (1) according to claim 1, characterized in that: The radius of curvature (R) satisfies the following relationship: in θ is the center angle of the waveform segment, l z is the chord length corresponding to the waveform segment, and m is an integer greater than 1; and / or The optical fiber clamp (1) also has an arc-shaped curved winding portion (1B) suitable for winding the non-clamped portion of the clamped optical fiber thereon.

3. The optical fiber clamp (1) according to claim 2, characterized in that: The optical fiber clamp (1) comprises a first clamping block (11) and a second clamping block (12), wherein the first clamping block (11) comprises a first wavy clamping surface (111), and the second clamping block (12) comprises a second wavy clamping surface (121) which is opposite to the first wavy clamping surface (111) and matches the first wavy clamping surface (111), and the first clamping block (11) is configured to be movable and fixable relative to the second clamping block (12) between a first position where the first clamping surface (111) and the second clamping surface (121) are in surface contact and a second position where the first clamping surface (111) and the second clamping surface (121) are separated by a predetermined distance. Each of the wavy clamping sections has at least three continuous wavy sections; The central angle (θ) of each wave segment of the at least one wave-shaped clamping section is less than 90 degrees; and / or The radius of curvature of the curved winding portion (1B) depends on the tensile strength of the clamped optical fiber.

4. The optical fiber clamp (1) according to claim 3, characterized in that: The circumference of the first clamping block (11) includes an arc-shaped first section and an arc-shaped second section which are continuous with each other in the circumferential direction, the first section serves as the first clamping surface (111), and the second section serves as the curved winding surface (112) of the curved winding portion (1B); and / or The diameter (D) of the curved winding portion (1B) is more than 200 times the diameter of the clamped optical fiber.

5. The optical fiber clamp (1) according to claim 3 or 4, characterized in that: The curved clamping portion (1A) is formed as a whole in a minor arc shape, and the curved winding portion (1B) is formed in a major arc shape; The second clamping block (12) comprises a boss portion (12A) and a bearing portion (12B), the bearing portion (12B) is formed with a bearing plane (122) for bearing the first clamping block (11), the boss portion (12A) protrudes from the bearing plane (122) and is formed with the second clamping surface (121), and the first clamping block (11) is configured to be suitable for sliding and fixing along the bearing plane (122) close to and away from the second clamping surface (121); and / or The optical fiber clamp (1) also has a position locking mechanism (13) suitable for locking and releasing the first clamping block (11) relative to the second clamping block (12).

6. A fiber laser (100), characterized in that: The fiber laser (100) comprises: Indicator light module (20); a resonant cavity module (40); and A reverse light isolation module (30) is arranged between the indicator light module (20) and the resonant cavity module (40), and comprises a long-period grating component (31) and a cladding light filter (32) consisting of at least one optical fiber clamp (1) according to any one of claims 1 to 5 and a clamped optical fiber.

7. The fiber laser (100) according to claim 6, characterized in that: The indicator light from the indicator light module (20) is input into the reverse light isolation module (30) from the cladding light filter (32) side, and is input into the resonant cavity module (40) after passing through the reverse light isolation module (30); and / or The long period grating component (31) is configured to couple the reversely transmitted core laser from the resonant cavity module (40) to the cladding, and the cladding light filter (32) is suitable for eliminating the laser coupled to the cladding.

8. The fiber laser (100) according to claim 7, characterized in that: The curved clamping portion (1A) of at least one optical fiber clamp (1) of the long period grating assembly (31) comprises: The first corrugated clamping section and its corresponding clamped optical fiber section are configured to couple the reversely transmitted signal light from the resonant cavity module (40) to the first long period grating of the cladding.

9. The fiber laser (100) according to claim 8, characterized in that: The curved clamping portion (1A) of at least one optical fiber clamp (1) of the long period grating assembly (31) further comprises: a second corrugated clamping section, the second corrugated clamping section and its corresponding clamped fiber section being configured to couple the reverse propagating Raman light from the resonant cavity module (40) to a second long period grating of the cladding; and / or A third corrugated clamping section, wherein the third corrugated clamping section and its corresponding clamped optical fiber section are configured to couple the counter-propagating pump light from the resonant cavity module (40) to the third long period grating of the cladding.

10. The fiber laser (100) according to any one of claims 6 to 9, characterized in that: The clamped optical fiber is arranged to be wound around a first clamping block (11) of the optical fiber clamp (1) having a circumferentially continuous first clamping surface (111) and a curved winding surface (112) for at least one turn, and is clamped by a corresponding wavy clamping section of the curved clamping portion (1A) at the first clamping surface (111); The optical fiber laser (100) further comprises a mode matcher (50) arranged between the indicator light module (20) and the reverse light isolation module (30); and / or The resonant cavity module (40) comprises a forward pump source (41), a forward beam combiner (42), a high-reflection Bragg grating (43), a gain optical fiber (44), a low-reflection Bragg grating (45), a reverse beam combiner (46), a reverse pump source (47), another cladding light filter and an output head (49) which are sequentially arranged along the forward output direction of the indicator light module (20).

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