Cladding light stripper and manufacturing method therefor, and optical fiber laser

Abstract

A cladding light stripper and a manufacturing method therefor, and an optical fiber laser, relating to the technical field of cladding light strippers. The cladding light stripper (100) comprises a double-clad optical fiber assembly (1) and triple-clad bare fibers (2); the double-clad optical fiber assembly (1) comprises two sections of double-clad optical fibers (11), each double-clad optical fiber (11) comprises a double-clad bare fiber (111) and a coating layer (112) which are concentrically arranged in sequence from inside to outside, and the double-clad bare fiber (111) extends out of the coating layer (112); there are multiple sections of triple-clad bare fibers (2), the multiple sections of triple-clad bare fibers (2) are sequentially welded to form a main body (3), the two sections of double-clad optical fibers (11) are respectively welded to two ends of the main body (3) by means of the double-clad bare fibers (111), and a stripper is formed on the main body (3). The cladding light stripper (100) can be constructed from multiple sections of triple-clad bare fibers (2) while preserving the original advantages of the double-clad optical fibers (11) and the triple-clad bare fibers (2); this design can avoid the formation of local hot spots in any section of triple-clad bare fiber (2) due to prolonged high-power operation, thereby significantly improving the cladding light stripping ability of the cladding light stripper (100).

Description

Cladding optical stripper and its fabrication method, fiber laser Technical Field

[0001] This invention relates to the field of cladding optical stripper technology, and particularly to a cladding optical stripper and its manufacturing method, as well as a fiber laser. Background Technology

[0002] Due to factors such as fiber splice loss, mode field mismatch, incomplete absorption of pump light by the gain fiber, and amplified spontaneous emission light, high-power fiber lasers accumulate a large amount of cladding light in the fiber cladding during laser transmission. If this light is allowed to accompany the laser output, it will not only affect the beam quality of the laser source but also cause the laser output pigtail to heat up, which can lead to serious damage.

[0003] Therefore, a cladding stripper is needed in fiber lasers. The cladding stripper is a core component for stable operation of fiber lasers, playing a role in stripping cladding light and optimizing beam quality. Its design principle is to disrupt the total internal reflection condition of the cladding light, thereby releasing the cladding light from the fiber cladding. The stripped cladding light is absorbed by the metal shell and converted into heat. Currently, cladding strippers exhibit localized hot spots during use, preventing the stripping of too much cladding light, which is detrimental to the filtering of cladding light in ultra-high power lasers. Summary of the Invention

[0004] The main objective of this invention is to propose a cladding light stripper and its manufacturing method, as well as a fiber laser, in order to solve the technical problem that existing cladding light strippers have local hot spots, which leads to the inability to strip too much cladding light.

[0005] To achieve the above objectives, according to one aspect of the present invention, a cladding optical stripper is provided, comprising:

[0006] A double-clad optical fiber assembly, comprising two double-clad optical fibers, each of the double-clad optical fibers comprising a double-clad bare fiber and a coating layer sequentially arranged from the inside to the outside, the double-clad bare fiber extending beyond the coating layer;

[0007] The triple-clad bare fiber consists of multiple segments, which are sequentially fused together to form a main body. Two segments of double-clad optical fiber are fused to both ends of the main body via the double-clad bare fiber. A stripper is formed on the main body.

[0008] In one embodiment, the number of the three-clad bare fibers is three segments.

[0009] In one embodiment, the three-clad bare fiber includes a first fiber core, an inner cladding, and a first outer cladding, which are sequentially arranged from the inside to the outside. The outer diameter of the inner cladding of each of the three-clad bare fibers is different, and the three segments of the three-clad bare fiber are fused together sequentially according to the outer diameter of the inner cladding from largest to smallest.

[0010] In one embodiment, the double-clad bare fiber includes a second core and a second outer cladding layer sequentially arranged from the inside to the outside, wherein the diameters of the first core and the second core are equal.

[0011] In one embodiment, the outer diameter of the first outer layer is equal to the outer diameter of the second outer layer.

[0012] In one embodiment, the core numerical aperture of the double-clad bare fiber is equal to that of the triple-clad bare fiber.

[0013] According to another aspect of the present invention, a fiber laser is also provided, the fiber laser comprising the cladding stripper described above.

[0014] According to another aspect of the present invention, a method for manufacturing a cladding optical stripper is also provided. This method is applied to the cladding optical stripper as described above, and includes the following steps:

[0015] Fabricate two sections of the double-clad bare fiber extending beyond the coating layer;

[0016] The main body is fabricated using the three-layered bare fiber.

[0017] The two bare double-clad optical fibers of the two segments are respectively fused to both ends of the main body;

[0018] A peeler is fabricated on the main body.

[0019] In one embodiment, fabricating two segments of the double-clad bare fiber extending beyond the coating layer of the double-clad optical fiber includes the following steps:

[0020] Take a section of the double-clad optical fiber assembly;

[0021] The coating layer of the middle portion of the double-clad fiber assembly is peeled off to expose the bare double-clad fiber, and the bare double-clad fiber is then cleaned.

[0022] The double-clad bare fiber is cut with a fiber optic cleaver to form two segments of the double-clad fiber.

[0023] In one embodiment, the fabrication of the main body includes the following steps:

[0024] Take three segments of triple-clad optical fiber, completely strip the coating of each segment of triple-clad optical fiber to form three segments of triple-clad bare fiber, and clean the triple-clad bare fiber.

[0025] Use a fiber optic cleaver to cut both sides of each segment of the triple-clad bare fiber;

[0026] Three bare fiber segments with triple cladding are fused together using an optical fiber fusion splicer to form the main body.

[0027] In the above scheme, the cladding optical stripper includes a double-clad fiber assembly and a triple-clad bare fiber. The double-clad fiber assembly includes two segments of double-clad fiber. Each double-clad fiber includes a double-clad bare fiber and a coating layer sequentially arranged from the inside to the outside, with the double-clad bare fiber extending beyond the coating layer. The triple-clad bare fiber consists of multiple segments, which are sequentially fused together to form a main body. The two segments of double-clad fiber are fused to both ends of the main body via the double-clad bare fiber, and the stripper is formed on the main body. Specifically, a relatively long section of double-clad optical fiber, i.e., the aforementioned double-clad optical fiber assembly, is taken. The coating layer in the middle part of the double-clad optical fiber assembly is peeled off, and the exposed bare double-clad fiber is cleaned. Then, the bare double-clad fiber is cut with a fiber cleaver, thus forming two sections of double-clad optical fiber with the bare fiber extending beyond the coating layer. Next, multiple sections of triple-clad optical fiber are taken, and the coating layer of each triple-clad optical fiber is removed to expose the inner bare triple-clad fiber. The bare triple-clad fiber is then cleaned, and both sides of the bare triple-clad fiber are cut to make the sides neat. The three sections of bare triple-clad fiber are then fused together sequentially to form the main body. Then, two sections of double-clad optical fiber are fused to the two ends of the main body through the bare double-clad fiber. Finally, laser marking or chemical etching is used to complete the process. The stripper is fabricated on the surface of the main body using etching or a combination of both methods. When using a cladding optical stripper, the optical signal enters from one end of the double-clad fiber. At this time, the optical signal mainly propagates in the core, but some light may also exist in the inner cladding of the double-clad bare fiber as cladding light, and then be transmitted to the main body. The main body is composed of multiple segments of triple-clad bare fiber fused together. This changes the refraction path of the cladding light, causing the cladding light to enter the outer cladding of the triple-clad bare fiber or be scattered away, thus achieving cladding light stripping. In this invention, multiple segments of triple-clad bare fiber are used to fabricate the stripper, which can prevent a segment of triple-clad bare fiber from generating local hot spots due to long-term exposure to high power, thereby greatly improving the ability of the cladding optical stripper to strip cladding light. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 is a schematic diagram of an embodiment of the cladding optical stripper provided by the present invention;

[0030] Figure 2 is a structural schematic diagram of a main body embodiment provided by the present invention;

[0031] Figure 3 is a flowchart illustrating the fabrication method of the cladding optical stripper according to the first embodiment of the present invention;

[0032] Figure 4 is a flowchart illustrating the fabrication method of the cladding optical stripper according to the second embodiment of the present invention;

[0033] Figure 5 is a flowchart illustrating the fabrication method of the cladding optical stripper according to the third embodiment of the present invention.

[0034] Explanation of icon numbers:

[0035] 100. Cladding optical stripper; 1. Double-clad fiber assembly; 11. Double-clad fiber; 111. Double-clad bare fiber; 111a. Second fiber core; 111b. Second outer cladding; 112. Coating layer; 2. Triple-clad bare fiber; 21. First fiber core; 22. Inner cladding; 23. First outer cladding; 3. Main body.

[0036] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0039] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0040] Due to factors such as fiber splice loss, mode field mismatch, incomplete absorption of pump light by the gain fiber, and amplified spontaneous emission light, high-power fiber lasers accumulate a large amount of cladding light in the fiber cladding during laser transmission. If this light is allowed to accompany the laser output, it will not only affect the beam quality of the laser source but also cause the laser output pigtail to heat up, which can lead to serious damage.

[0041] Therefore, a cladding stripper is needed in fiber lasers. The cladding stripper is a core component for stable operation of fiber lasers, playing a role in stripping cladding light and optimizing beam quality. Its design principle is to disrupt the total internal reflection condition of the cladding light, thereby releasing it from the fiber cladding. The stripped cladding light is absorbed by the metal shell and converted into heat. Currently, cladding strippers are made of double-clad fiber. While double-clad fiber cladding strippers can strip cladding light, their efficiency is low, and local hot spots appear during use, preventing the stripping of too much cladding light, which is detrimental to the filtering of cladding light in ultra-high power lasers. To solve this problem, the applicant researched and used triple-clad fiber to fabricate the cladding stripper. Although this improved the efficiency of cladding light stripping, the problem of local hot spots still occurred during use. Furthermore, using fusion splicing to fabricate triple-clad fiber for the cladding stripper makes the manufacturing process more complex and costly, potentially increasing the overall cost of the laser system. To further eliminate local hot spots and control costs as much as possible, the applicant designed a new cladding stripper through research.

[0042] To achieve the above objectives, referring to Figures 1 and 2, according to one aspect of the present invention, a cladding optical stripper 100 is provided, comprising a double-clad optical fiber assembly 1 and a triple-clad bare fiber 2. The double-clad optical fiber assembly 1 includes two segments of double-clad optical fibers 11, each of which includes a double-clad bare fiber 111 and a coating layer 112 sequentially arranged from the inside to the outside, with the double-clad bare fiber 111 extending beyond the coating layer 112. The triple-clad bare fiber 2 consists of multiple segments, which are sequentially fused together to form a body 3. The two segments of double-clad optical fibers are fused to both ends of the body 3 via the double-clad bare fiber 111, and a stripper is formed on the body 3. Specifically, a relatively long section of double-clad optical fiber 11, namely the aforementioned double-clad optical fiber assembly 1, is taken. The coating layer 112 of the middle part of the double-clad optical fiber assembly 1 is peeled off, and then the exposed bare double-clad fiber 111 is cleaned. The bare double-clad fiber 111 is then cut using a fiber optic cleaver, thus forming two sections of double-clad optical fiber 11 with the bare double-clad fiber 111 extending from the coating layer 112. Then, multiple sections of triple-clad optical fiber are taken, and the coating layer 112 of each triple-clad optical fiber is removed, exposing the inner bare triple-clad fiber 2. The bare triple-clad fiber 2 is then cleaned, and both sides of the bare triple-clad fiber 2 are cut to make the sides neat. The three sections of bare triple-clad fiber 2 are then fused together sequentially to form the main body 3. Two sections of double-clad optical fiber 11 are then fused to both ends of the main body 3 via the double-clad fiber 111. Finally, the connection is made by excitation... A stripper is fabricated on the surface of the main body 3 by photo-marking, chemical etching, or a combination of both. When the cladding stripper 100 is used, the optical signal enters from the double-clad fiber 11 at one end. At this time, the optical signal mainly propagates in the core, but some light may also exist in the inner cladding 22 of the double-clad bare fiber 111 as cladding light, and then be transmitted to the main body 3. The main body 3 is composed of multiple segments of triple-clad bare fiber 2 fused together. This changes the refraction path of the cladding light, so that the cladding light enters the outer cladding of the triple-clad bare fiber 2 or is scattered away, thus achieving the stripping of the cladding light. In this embodiment, multiple segments of triple-clad bare fiber 2 are used to fabricate the stripper, which can prevent a segment of triple-clad bare fiber 2 from generating local hot spots due to long-term exposure to high power, thereby greatly improving the ability of the cladding stripper 100 to strip the cladding light.

[0043] Referring to Figures 1 and 2, in one embodiment, the number of triple-clad bare fibers 2 is three segments. The sequential splicing of these three segments of triple-clad fiber enables multi-stage optical stripping. Each segment of triple-clad fiber can further remove cladding light, thereby improving cladding light stripping efficiency. By progressively optimizing the parameters of each segment of triple-clad fiber, a finer optical stripping effect can be achieved, ensuring very high purity of the final output optical signal. The design of three segments of triple-clad fiber can better distribute heat, preventing local overheating and thus improving the thermal stability of the system. Effective thermal management helps extend the lifespan of fiber optic devices and improves the reliability and long-term stability of the system. While using more triple-clad bare fibers 2 for sequential splicing can further improve cladding light stripping efficiency, it will also increase the number of splice points, meaning a more complex overall structure and higher manufacturing difficulty. This embodiment uses three segments of triple-clad bare fibers 2, which reduces manufacturing difficulty while ensuring cladding light stripping efficiency.

[0044] Referring to Figures 1 and 2, in one embodiment, the triple-clad bare fiber 2 includes a first fiber core 21, an inner cladding 22, and a first outer cladding 23 arranged sequentially from the inside to the outside. The outer diameter of the inner cladding 22 of each triple-clad bare fiber 2 is different, and the three segments of triple-clad bare fiber 2 are fused together sequentially according to the outer diameter of the inner cladding 22 from largest to smallest. The three segments of triple-clad bare fiber 2 are fused together sequentially according to the decreasing outer diameter of the inner cladding 22, forming a gradient structure. The outer diameter of the inner cladding 22 in the first segment of triple-clad bare fiber 2 is the largest. When the optical signal propagates in this segment, the propagation path of the cladding light is relatively wide and easy to control and manage. The outer diameter of the inner cladding 22 in the second segment of triple-clad bare fiber 2 is the next smallest. When the optical signal propagates in this segment, the propagation path of the cladding light gradually narrows and begins to be more restricted. The outer diameter of the inner cladding 22 in the third segment of triple-clad bare fiber 2 is the smallest. When the optical signal propagates in this segment, the propagation path of the cladding light is further narrowed and it is easier to remove or scatter. The structural setting in this embodiment, by gradually reducing the outer diameter of the inner cladding 22, can more effectively remove unnecessary cladding light and further improve the cladding light stripping efficiency.

[0045] Referring to Figures 1 and 2, in one embodiment, the double-clad bare fiber 111 includes a second fiber core 111a and a second outer cladding layer 111b sequentially arranged from the inside out. The diameter of the first fiber core 21 is equal to that of the second fiber core 111a. The equal diameter of the first fiber core 21 and the second fiber core 111a means that the diameters of the double-clad bare fiber 111 and the triple-clad bare fiber 2 are the same in the core portion, thus ensuring that the transmission characteristics of the optical signal remain consistent within the core.

[0046] Referring to Figures 1 and 2, in one embodiment, the outer diameter of the first outer cladding layer 23 is equal to the outer diameter of the second outer cladding layer 111b. Setting the outer diameter of the second outer cladding layer 111b in the double-clad bare fiber 111 and the outer diameter of the first outer cladding layer 23 in the triple-clad bare fiber 2 to the same size ensures the quality of the splice during the splicing process of the double-clad bare fiber 111 and the triple-clad bare fiber 2. The quality of the splice ensures effective optical signal transmission while minimizing loss and reflection.

[0047] Referring to Figures 1 and 2, in one embodiment, the core numerical aperture of the double-clad bare fiber 111 is equal to that of the triple-clad bare fiber 2. The core numerical aperture is an important parameter of optical fiber, describing its ability to receive and transmit light. The size of the numerical aperture directly affects the coupling efficiency, transmission mode, and transmission performance of the optical fiber. In this embodiment, setting the core numerical apertures of the double-clad bare fiber 111 and the triple-clad bare fiber 2 to be equal ensures that the transmission characteristics of the optical signal remain consistent between different double-clad bare fibers 111 and triple-clad bare fibers 2, reducing splice loss and reflection.

[0048] According to another aspect of the present invention, a fiber laser is also provided, comprising the cladding stripper 100 described above. Since the fiber laser encompasses all embodiments of the aforementioned fiber laser embodiments, it possesses at least all the beneficial effects of all the aforementioned embodiments, which will not be elaborated upon here.

[0049] According to another aspect of the present invention, referring to FIG3, FIG3 is a schematic flowchart of the manufacturing method of the cladding optical stripper 100 according to the first embodiment of the present invention. The present invention also proposes a manufacturing method of the cladding optical stripper 100. The manufacturing method of the cladding optical stripper 100 is applied to the cladding optical stripper 100 as described above. The manufacturing method of the cladding optical stripper 100 includes the following steps:

[0050] S1. Fabricate two sections of double-clad bare fiber 111 extending out of the coating layer 112;

[0051] First, determine the length of the coating layer 112 that needs to be stripped and mark it on the double-clad fiber 11. Then, use a fiber stripper to carefully strip the coating layer 112 of the fiber according to the marked position to expose the inner double-clad bare fiber 111. Be careful to use moderate force to avoid damaging the inner fiber core.

[0052] S2. Take the three-layer bare fiber 2 to make the main body 3;

[0053] Select a triple-clad optical fiber, and then carefully strip the coating 112 of the triple-clad optical fiber according to the marked position using an optical fiber stripper to expose the inner triple-clad bare fiber 2. Then, fabricate the main body 3 through the triple-clad bare fiber 2.

[0054] S3. The two bare double-clad optical fibers 111 of the two double-clad optical fibers 11 are respectively fused to the two ends of the main body 3.

[0055] The two bare double-clad optical fibers 111 are cladly fused to both ends of the main body 3 using a fusion splicer.

[0056] S4. Make a peeler on the main body 3.

[0057] A peeler is made on the outer layer of the main body 3 by means of laser marking, chemical etching, or a combination of both.

[0058] In this embodiment, the length of the coating layer 112 to be stripped is first determined and marked on the double-clad optical fiber 11. Then, the coating layer 112 of the optical fiber is carefully stripped off according to the marked positions using an optical fiber stripper, exposing the inner double-clad bare fiber 111. A triple-clad optical fiber is selected, and the coating layer 112 of the triple-clad optical fiber is carefully stripped off according to the marked positions using an optical fiber stripper, exposing the inner triple-clad bare fiber 2. The body 3 is then fabricated using the triple-clad bare fiber 2. The two sections of double-clad optical fiber 11 are then fused to both ends of the body 3 via the double-clad bare fiber 111. Finally, a stripper is fabricated on the surface of the body 3 by laser marking, chemical etching, or a combination of both. When using the cladding optical stripper 10... At time 0, the optical signal enters from the double-clad fiber 11 at one end. At this time, the optical signal mainly propagates in the core, but some of the light may exist in the inner cladding 22 of the double-clad bare fiber 111 as cladding light, and then be transmitted to the main body 3. The main body 3 is composed of multiple segments of triple-clad bare fiber 2 fused together. This changes the refraction path of the cladding light, so the cladding light enters the outer cladding of the triple-clad bare fiber 2 or is scattered away, thus achieving cladding light stripping. By fusing the double-clad fiber 11 and the triple-clad bare fiber 2 to form a cladding light stripper 100, the overall performance and application range of the cladding light stripper 100 can be further improved while maintaining the original advantages of the double-clad fiber 11 and the triple-clad bare fiber 2.

[0059] Referring to Figure 4, which is a schematic flowchart of the fabrication method of the cladding optical stripper 100 according to the second embodiment of the present invention, in one embodiment, fabricating two sections of double-clad bare fiber 111 extending out of the coating layer 112 includes the following steps:

[0060] S11. Take a section of double-clad optical fiber assembly 1;

[0061] Select a relatively long section of double-clad optical fiber 11, which is equivalent to double-clad optical fiber assembly 1, and then mark the middle part of the double-clad optical fiber.

[0062] S12. Peel off the coating layer 112 of the middle part of the double-clad fiber assembly 1 to expose the double-clad bare fiber 111, and clean the double-clad bare fiber 111.

[0063] The operator carefully strips the coating 112 of the middle part of the double-clad fiber 11 according to the marked positions using a fiber stripper, exposing the inner double-clad bare fiber 111 in the middle part of the double-clad fiber 11. Then the double-clad bare fiber 111 is cleaned to prevent dust or impurities from affecting subsequent operations.

[0064] S13. The double-clad bare fiber 111 is cut with a fiber optic cleaver to form two segments of double-clad fiber 11.

[0065] After cleaning, the workers used a fiber optic cleaver to cut the exposed double-clad bare fiber 111, and then smoothed the cut surface.

[0066] In this embodiment, a relatively long double-clad optical fiber 11 is selected, which is equivalent to the double-clad optical fiber assembly 1. Then, a mark is made on the middle part of the double-clad optical fiber 11. The operator carefully removes the coating 112 of the middle part of the double-clad optical fiber 11 according to the marked position using an optical fiber stripper, exposing the inner double-clad bare fiber 111. Then, the double-clad bare fiber 111 is cleaned to prevent dust or impurities from affecting subsequent operations. After cleaning, the operator uses an optical fiber cleaver to cut the exposed double-clad bare fiber 111, and then performs flattening treatment on the cut cross-section. Generally speaking, the lengths of the two double-clad optical fiber segments 11 after cutting are the same, and the lengths of the double-clad bare fiber 111 extending are the same, so that the subsequent fabrication of the cladding optical stripper 100 is more aesthetically pleasing.

[0067] Referring to Figure 5, which is a flowchart illustrating the fabrication method of the cladding optical stripper 100 according to the third embodiment of the present invention, in one embodiment, the fabrication of the main body 3 includes the following steps:

[0068] S21. Take three segments of triple-clad optical fiber, completely peel off the coating layer 112 of each segment of triple-clad optical fiber to form three segments of triple-clad bare fiber 2, and clean the triple-clad bare fiber 2.

[0069] Three segments of triple-clad optical fibers with different outer diameters of inner cladding 22 are selected. The lengths of these three segments of triple-clad optical fibers can be equal or unequal. Then, the coating 112 of the three segments of triple-clad optical fibers is completely stripped off, exposing all the bare triple-clad fibers 2 in the triple-clad optical fibers. Then, the bare triple-clad fibers 2 are cleaned.

[0070] S22. Use a fiber optic cleaver to cut both sides of each section of triple-clad bare fiber 2;

[0071] After the coating layer 112 is completely stripped, the operator uses an optical fiber cutter to cut both sides of each section of the triple-clad bare fiber 2, so that both sides of each section of the triple-clad bare fiber 2 are neat, which facilitates subsequent fusion splicing.

[0072] S23. The three sections of triple-clad bare fiber 2 are fused together using an optical fiber fusion splicer to form the main body 3.

[0073] The workers arranged the three sections of triple-clad bare fiber 2 in descending order of the outer diameter of the inner cladding 22, and then fused them sequentially using a fiber optic fusion splicer to form the main body 3.

[0074] In this embodiment, the sequential fusion splicing of three segments of triple-clad optical fibers enables multi-stage optical stripping. Each segment of triple-clad optical fiber can further remove cladding light, thereby improving the cladding light stripping efficiency. By progressively optimizing the parameters of each segment of triple-clad optical fiber, a more refined optical stripping effect can be achieved, ensuring a very high purity of the final output optical signal. The design of three segments of triple-clad optical fibers can better distribute heat and prevent local overheating, thereby improving the thermal stability of the system. Effective thermal management helps extend the service life of optical fiber devices and improve the reliability and long-term stability of the system. The three segments of triple-clad bare fiber 2 are sequentially fused according to the outer diameter of the inner cladding 22 from large to small, forming a gradient structure. In the first segment of the triple-clad bare fiber 2, the outer diameter of the inner cladding 22 is the largest. When the optical signal propagates in this segment, the propagation path of the cladding light is relatively wide and easy to control and manage. In the second segment of the triple-clad bare fiber 2, the outer diameter of the inner cladding 22 is the second largest. When the optical signal propagates in this segment, the propagation path of the cladding light gradually narrows and begins to be more restricted. In the third segment of the triple-clad bare fiber 2, the outer diameter of the inner cladding 22 is the smallest. When the optical signal propagates in this segment, the propagation path of the cladding light becomes even narrower and easier to remove or scatter. The structural configuration in this embodiment, by gradually reducing the outer diameter of the inner cladding 22, can more effectively remove unnecessary cladding light and further improve the cladding light stripping efficiency.

[0075] An example is given based on the manufacturing method of the cladding optical stripper 100 described above:

[0076] The first step is to take a section of double-clad fiber assembly 1, peel off the middle coating layer 112 of the double-clad fiber assembly 1, the peeling length of the coating layer 112 is 3cm, then clean the double-clad bare fiber 111 part, and use a fiber optic cleaver to cut the middle double-clad bare fiber 111 area, splitting the double-clad fiber assembly 1 into two parts, forming two sections of double-clad bare fiber 111 extending out of the coating layer 112, wherein the diameter of the second core 111a in the double-clad bare fiber 111 is 50um, the outer diameter of the second outer cladding layer 111b in the double-clad bare fiber 111 is 360um, and the core numerical aperture is 0.22.

[0077] The second step involves taking three segments of triple-clad optical fiber and completely stripping the coating 112 of the triple-clad optical fiber to form three segments of bare triple-clad fiber 2. The diameter of the first core 21 of each of the three segments of bare triple-clad fiber 2 is 50 μm, the outer diameter of the first outer cladding 23 of each of the three segments of bare triple-clad fiber 2 is 360 μm, and the outer diameters of the inner cladding 22 of each of the three segments of bare triple-clad fiber 2 are 300 μm, 150 μm, and 70 μm, respectively. Then, the three segments of bare triple-clad fiber 2 are cleaned, and the two ends of each segment of bare triple-clad fiber 2 are cut with a fiber optic cleaver to make the ends of the three segments of bare triple-clad fiber 2 flat. The numerical aperture of the core of each of the three segments of bare triple-clad fiber 2 is 0.22.

[0078] The third step is to arrange the three bare fiber segments 2 with three cladding layers in descending order of the outer diameter of the inner cladding layer 22, and then fuse them together using a fiber optic fusion splicer to form the main body 3.

[0079] The fourth step involves splicing the two double-clad optical fibers 11 to both ends of the main body 3 via double-clad bare fibers 111. The outer diameter of the second outer cladding 111b in the double-clad bare fiber 111 is the same as the outer diameter of the first outer cladding 23 in the triple-clad bare fiber 2, which makes the splicing more stable. The diameter of the second core 111a in the triple-clad bare fiber 2 is the same as the diameter of the first core 21 in the triple-clad bare fiber 2, which ensures that the transmission characteristics of the optical signal in the core remain consistent. The numerical aperture of the core of the double-clad bare fiber 111 is the same as the numerical aperture of the core of the triple-clad bare fiber 2, which ensures that the transmission characteristics of the optical signal remain consistent between different double-clad bare fibers 111 and triple-clad bare fibers 2, reducing the loss and reflection at the splice point.

[0080] The fifth step is to create a stripper on the first outer cladding layer 23 of the main body 3. The method can be laser marking, chemical etching, or a combination of both. In this way, when the cladding light enters the main body 3, the cladding light is gradually stripped off from the first outer cladding layer 23.

[0081] In summary, by using multiple segments of triple-clad bare fiber 2 to fabricate the stripper, it is possible to prevent a segment of triple-clad bare fiber 2 from generating local hot spots due to prolonged exposure to high power, thereby greatly improving the ability of the cladding stripper 100 to strip cladding light.

[0082] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A cladding light stripper, characterized by, The application relates to a double-clad optical fiber assembly, which comprises two double-clad optical fibers, each of which comprises a double-clad bare fiber and a coating layer, and a three-clad bare fiber. The three-clad bare fiber is divided into three segments, and the two double-clad optical fibers are respectively connected to the two ends of the main body through the double-clad bare fibers. The three-clad bare fiber is divided into three segments.

2. The cladding light stripper of claim 1, wherein The three-clad bare fiber comprises a first core, an inner cladding and a first outer cladding, and the outer diameters of the inner claddings of the three segments of the three-clad bare fiber are different.

3. The cladding light stripper of claim 2, wherein, The first core and the second core have the same diameter.

4. The cladding light stripper of claim 3, wherein The outer diameter of the first outer cladding is equal to that of the second outer cladding.

5. The cladding light stripper of claim 4, wherein, The numerical aperture of the core of the double-clad bare fiber is equal to that of the core of the three-clad bare fiber.

6. The cladding light stripper of claim 4, wherein, The fiber laser comprises the cladding light stripper according to any one of claims 1 to 6.

7. A fiber laser, characterized by, The manufacturing method of the cladding light stripper comprises the following steps:

8. A method of manufacturing a cladding light stripper applied to the cladding light stripper according to any one of claims 1 to 6, characterized by, manufacturing the double-clad optical fibers with the double-clad bare fibers of the two segments extending out of the coating layer; manufacturing the main body by using the three-clad bare fibers; connecting the double-clad bare fibers of the two double-clad optical fibers to the two ends of the main body respectively; manufacturing the stripper on the main body. The manufacturing of the double-clad optical fibers with the double-clad bare fibers of the two segments extending out of the coating layer comprises the following steps:

9. The method of claim 8, wherein the cladding optical stripper is formed by, taking one double-clad optical fiber assembly; stripping the coating layer of the middle part of the double-clad optical fiber assembly to expose the double-clad bare fiber and cleaning the double-clad bare fiber; cutting the double-clad bare fiber by using a fiber cutting knife to form two double-clad optical fibers. The manufacturing of the main body comprises the following steps:

10. The method of claim 8, wherein the cladding light stripper is formed by, taking three three-clad optical fibers, completely stripping the coating layer of each three-clad optical fiber to form three three-clad bare fibers, and cleaning the three three-clad bare fibers; cutting the two sides of each three-clad bare fiber by using a fiber cutting knife; connecting the three three-clad bare fibers to each other by using a fiber fusion machine to form the main body. ​

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