Multifunctional optical fiber combiner and manufacturing method thereof

Abstract

The present invention discloses a multifunctional optical fiber combiner and its manufacturing method. The combiner includes an input signal optical fiber, an output signal optical fiber, a pump optical fiber, a coupling optical fiber, and a quartz tube; the pump optical fiber is arranged on the outer wall of the output signal optical fiber, and the optical fiber bundle is tapered and fused to the input signal optical fiber; the quartz tube with a roughened outer wall is sleeved on the input signal optical fiber, and scattering is performed through the outer wall of the quartz tube to prevent high-order modes from causing heating of the coating layer; the other end of the output signal optical fiber and the cladding of the coupling optical fiber are corroded to a preset thickness, and the corroded areas of the two are melted and tapered to a preset fusion length and preset fusion depth to filter out Raman laser. The present invention roughens the outer wall of the quartz tube to remove high-order modes with large numerical aperture, reducing the problem of coating heating; the pump laser remaining in the input signal optical fiber is transmitted to the cladding of the output signal optical fiber and then stripped through the corroded area of ​​the output signal optical fiber.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular to a multifunctional optical fiber combiner and a manufacturing method thereof. Background Art

[0002] With the widespread and in-depth application of intelligent manufacturing in the industrial field, fiber lasers have gradually become the mainstream products of industrial lasers due to their advantages such as small size, high brightness, and flexible pigtails. They play an increasingly important role in the fields of fine material cutting, welding, engraving, micromachining, etc. Due to the power limitation of semiconductor pump sources, in order to achieve high-brightness laser output of kilowatts or even higher powers, a fiber combiner is needed to combine multiple pump sources to enhance the power of the pump sources.

[0003] Commonly used fiber combiners include end-pump and side-pump combiners. By combining and fusing multiple pump fibers and signal fibers, they can output multiple pump lasers and signal lasers from a single fiber. The main methods for making a combiner include: combining, tapering, cutting, and splicing. For example, after combining multiple pump fibers and a single signal fiber, the outer diameter of the fiber bundle is tapered to a size close to the outer diameter of the output signal fiber. The fiber bundle is then cut and the fiber bundle with a smooth end face is fused to the signal fiber to complete the fiber combiner. Side-pump combiners are primarily made by pre-tapering the input pump fiber and then attaching it to the output signal fiber and fusing them together.

[0004] Fiber combiners often have the following problems in laser system applications: heating of the coating layer of the output double-clad fiber, a large amount of residual pump laser at the output end of the combiner, and stimulated Raman scattering laser at the output end of the combiner under high power conditions. If these problems are not dealt with in a timely manner, they may cause damage to the combiner device or even the entire laser.

[0005] In view of this, overcoming the defects of the prior art is an urgent problem to be solved in this technical field. Summary of the Invention

[0006] The technical problem to be solved by the present invention is how to solve the problems of heating of the coating layer of the input double-clad optical fiber in the laser of the existing optical fiber combiner, excessive residual pump laser at the output end of the combiner, and stimulated Raman scattering laser at the output end of the combiner under high power of the pump laser.

[0007] The present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a multifunctional fiber combiner comprising at least one pump fiber 1, an output signal fiber 2, a quartz tube 3, an input signal fiber 4, and a coupling fiber 5;

[0009] The pump fiber 1 is arranged on the outer wall of one end of the output signal fiber 2, and the end of the fiber bundle composed of the pump fiber 1 and the output signal fiber 2 is connected to the end of the input signal fiber 4 to facilitate the combination of the fiber pump signal;

[0010] The inner diameter of the quartz tube 3 is greater than the outer diameter of the input signal optical fiber 4 by a preset length. The quartz tube 3 is sleeved on the input signal optical fiber 4, and a glue layer 6 is filled between the inner wall of the quartz tube 3 and the outer wall of the input signal optical fiber 4. The outer wall of the quartz tube 3 is roughened. When high-order modes are transmitted to the outer wall of the quartz tube 3, they are scattered by the roughened outer wall of the quartz tube 3, thereby preventing the high-order modes from causing heating of the coating layer of the input signal optical fiber 4;

[0011] The cladding of the output signal optical fiber 2 at a preset length from the other end is etched to a preset thickness, and the cladding at a preset distance from one end of the coupling optical fiber 5 is etched to a preset thickness, and the output signal optical fiber 2 and the coupling optical fiber 5 at the etched location are fused to a preset fusion length and a preset fusion depth, so as to filter out the Raman laser generated in the optical fiber combiner.

[0012] Preferably, the refractive index of the quartz tube 3 is not less than the refractive index of the glue layer 6 , and the refractive index of the glue layer 6 is not less than the refractive index of the coating layer of the input signal optical fiber 4 .

[0013] Preferably, the quartz tube 3, the input signal optical fiber 4 and the glue layer 6 are coaxially arranged.

[0014] Preferably, the diameter of the corroded portion of the output signal optical fiber 2 is equal to the diameter of the corroded portion of the coupling optical fiber 5 .

[0015] Preferably, the signal laser in the output signal optical fiber 2, the Raman laser in the output signal optical fiber 2, the coupling coefficient of the signal laser in the output signal optical fiber 2, and the coupling coefficient of the Raman laser in the output signal optical fiber 2 satisfy the following formula:

[0016]

[0017]

[0018]

[0019]

[0020] Wherein, λ1 represents the wavelength of the signal laser of the output signal optical fiber 2, and λ2 represents the wavelength of the Raman laser in the output signal optical fiber 2. represents the coupling coefficient of the signal laser, represents the coupling coefficient of the Raman laser, and Z represents the fusion length.

[0021] Preferably, the output signal optical fiber 2 and the coupling optical fiber 5 are cut from the same optical fiber, so as to ensure that the parameters of the output signal optical fiber 2 and the coupling optical fiber 5 are the same.

[0022] Preferably, the outer wall of the quartz tube 3 is roughened by solution etching or laser micromachining.

[0023] Preferably, the output signal optical fiber 2 at the corroded portion and the coupling optical fiber 5 at the corroded portion are connected by heating and melting through an oxyhydrogen flame or a graphite filament.

[0024] In a second aspect, relative to the multifunctional optical fiber combiner of the first aspect, the present invention further provides a method for manufacturing the multifunctional optical fiber combiner, comprising:

[0025] At least one pump fiber 1 is evenly arranged on the outer wall of one end of the output signal fiber 2 to form a fiber bundle, and the input signal fiber 4 is fused with the fiber bundle to form a pump laser beam combining structure;

[0026] The quartz tube 3 is sleeved on the pump laser beam combining structure, and glue is filled and cured between the inner wall of the quartz tube 3 and the outer wall of the pump laser beam combining structure, and the outer wall of the quartz tube 3 is roughened. The glue layer 6 formed by the glue, the quartz tube 3, and the pump laser beam combining structure are coaxially arranged.

[0027] The cladding at a preset distance from the other end of the output signal optical fiber 2 and at a preset position of the coupling optical fiber 5 is etched to a preset thickness, and the output signal optical fiber 2 and the coupling optical fiber 5 at the etched location are fused to a preset fusion length and a preset fusion depth to complete the production of the multifunctional optical fiber combiner.

[0028] Preferably, the method further includes determining whether to fuse the output signal optical fiber 2 at the corroded location and the coupling optical fiber 5 at the corroded location to a preset fusion length and a preset fusion depth, specifically comprising:

[0029] Laminating the output signal fiber 2 to the etched area of ​​the coupling fiber 5, heating the etched area to a molten state, and then performing a tapering process;

[0030] During the tapering process, the signal laser and the Raman laser are input into the fiber combiner through the input signal fiber 4. The tapering is stopped when the Raman laser power in the coupling fiber 5 and the signal laser power in the output signal fiber 2 are the maximum.

[0031] When the Raman laser power in the coupling optical fiber 5 and the signal laser power in the output signal optical fiber 2 are the maximum, the output signal optical fiber 2 and the coupling optical fiber 5 at the corresponding corroded location are melted to a preset fusion length and a preset melting depth.

[0032] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows: in the embodiments of the present invention, by roughening the outer wall of the quartz tube 3, the total reflection structure of the outer wall of the quartz tube 3 is destroyed, and the high-order modes with large numerical aperture are stripped away, thereby reducing the problem of heating of the coating layer; after the residual pump light in the laser light path is transmitted to the cladding of the output signal optical fiber 2, the residual pump laser is stripped away after passing through the corroded area of ​​the output signal optical fiber 2; in addition, by fusing the output signal optical fiber 2 at the corroded location and the coupling optical fiber 5 at the corroded location to a preset fusion length and a preset fusion depth, the purpose of filtering out the Raman laser in the laser is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0034] Figure 1 This is a schematic structural diagram of a multifunctional optical fiber combiner provided by the present invention;

[0035] Figure 2 This is a schematic structural diagram of a quartz tube of a multifunctional optical fiber combiner provided by the present invention;

[0036] Figure 3 This is a schematic diagram of the cross-sectional structure of a quartz tube of a multifunctional optical fiber combiner provided by the present invention after assembly;

[0037] Figure 4 This is a schematic structural diagram of a multifunctional fiber combiner provided by the present invention, in which the coupling fiber and the other end of the output signal fiber are fused together;

[0038] Figure 5 This is a schematic diagram of the principle of stripping residual pump laser of a multifunctional optical fiber combiner provided by the present invention;

[0039] Figure 6 This is a schematic diagram of the principle of stripping the high-order mode of the coating of the input signal optical fiber of a multifunctional optical fiber combiner provided by the present invention;

[0040] Figure 7 This is a flow chart of a method for manufacturing a multifunctional optical fiber combiner provided by the present invention;

[0041] Wherein, the reference numerals:

[0042] 1-Pump fiber; 2-Output signal fiber; 3-Quartz tube; 4-Input signal fiber; 5-Coupling fiber; 6-Glue layer. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] In the description of the present invention, the terms "inside", "outside", "longitudinal", "lateral", "upper", "lower", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0045] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] Embodiment 1:

[0047] Embodiment 1 of the present invention provides a multifunctional optical fiber combiner, such as Figure 1 As shown, it includes at least one pump fiber 1, an output signal fiber 2, a quartz tube 3, an input signal fiber 4 and a coupling fiber 5;

[0048] The pump fiber 1 is arranged on the outer wall of one end of the output signal fiber 2, and the end of the fiber bundle composed of the pump fiber 1 and the output signal fiber 2 is connected to the end of the input signal fiber 4 to facilitate the combination of the fiber pump signal;

[0049] The inner diameter of the quartz tube 3 is greater than the outer diameter of the input signal optical fiber 4 by a preset length. The quartz tube 3 is sleeved on the input signal optical fiber 4, and a glue layer 6 is filled between the inner wall of the quartz tube 3 and the outer wall of the input signal optical fiber 4. The outer wall of the quartz tube 3 is roughened. When high-order modes are transmitted to the outer wall of the quartz tube 3, they are scattered by the roughened outer wall of the quartz tube 3, thereby preventing the high-order modes from causing heating of the coating layer of the input signal optical fiber 4;

[0050] Among them, in a universal understanding, "high-order mode" and "low-order mode" are interpreted as follows: light can be transmitted in a multimode optical fiber along many possible paths, and these paths have different loss characteristics. The paths or modes confined to the center of the optical fiber core are called "low-order modes", while those paths or modes that are transmitted close to the core / cladding interface are called "high-order modes". For the present invention, it can be understood that the corresponding pump laser when the incident angle is greater than or equal to the critical angle of total reflection is called "low-order mode", and the corresponding pump laser when the incident angle is less than the critical angle of total reflection is called "high-order mode". It is worth noting that the angle between the pump laser of the present invention and the normal to the axial direction of the output signal optical fiber 2 is called the incident angle.

[0051] The cladding of the output signal optical fiber 2 at a preset length from the other end is etched to a preset thickness, and the cladding at a preset distance from one end of the coupling optical fiber 5 is etched to a preset thickness, and the output signal optical fiber 2 and the coupling optical fiber 5 at the etched location are fused to a preset fusion length and a preset fusion depth to facilitate filtering out the Raman laser in the laser.

[0052] like Figure 1 As shown, the fiber combiner of the embodiment of the present invention includes three parts. The first part includes a structure consisting of at least one pump fiber 1, an input signal fiber 4 and one end of an output signal fiber 2. In the first part, the pump fiber 1 is arranged on the outer wall of one end of the output signal fiber 2 to form a fiber bundle containing the pump fiber 1 and the output signal fiber 2. The fiber bundle is coupled with the input signal fiber 4 after being tapered to form the first part of the embodiment of the present invention, which is mainly used to combine the pump signal. Figure 2 and Figure 3 As shown, the second part includes a quartz tube 3 and an input signal optical fiber 4, wherein the input signal optical fiber 4 plays the role of input signal laser. The quartz tube 3 is the main structure of the second part. The outer wall of the quartz tube 3 is roughened to destroy the total reflection structure of the outer wall of the quartz tube 3, so that part of the high-order mode can be scattered outside the device. It is mainly used to prevent the coating layer outside the cladding of the input signal optical fiber 4 from absorbing too many high-order modes and generating too much heat, thereby avoiding overheating of the coating layer of the input signal optical fiber, resulting in a reduction in the life of the coating layer or even damage. Figure 4 As shown, the third part includes the other end of the output signal fiber 2 and the coupling fiber 5. The cladding at a preset distance from the end of the other end of the output signal fiber 2 is etched, and the cladding of the coupling fiber 5 is etched (usually, most of the cladding of the output signal fiber 2 and the coupling fiber 5 is removed by etching. The specific size is determined according to the actual situation. After etching, the diameters of the coupling fiber 5 and the output signal fiber 2 in the etched area must be equal). The etched areas of the coupling fiber 5 and the output signal fiber 2 are melted to form the third part of the embodiment of the present invention. It is worth noting that Figure 1The signal laser propagates from the right to the left. Figure 4 The structural correspondence in Figure 1 In the structure on the left side of the figure, in the process of actually manufacturing the optical fiber combiner of the embodiment of the present invention, the output signal optical fiber 2 and the coupling optical fiber 5 are usually fused together (corresponding to Figure 4 The structure in the figure) cuts off the coupling fiber 5 on the front side of the laser transmission (in Figure 4 The transmission of the laser signal is from left to right, that is, cut off Figure 4 In the first structure of the embodiment of the present invention, the residual pump laser in the laser enters the cladding of the output signal fiber 2 through the input signal fiber 4; Figure 5 As shown, the residual pump laser is transmitted in the cladding, and after passing through the corrosion area of ​​the output signal optical fiber 2 of the third part, the residual pump light is stripped off, effectively avoiding the influence of the residual pump laser on the laser; in addition, as shown Figure 6 As shown, the outer wall of the quartz tube 3 in the second part of the structure is roughened, which destroys the total reflection structure of the outer wall of the quartz tube 3, and can effectively strip the high-order mode signal laser with a large numerical aperture incident at a certain angle, thereby reducing the problem of heating of the coating layer of the input signal optical fiber 4. It is worth noting that the number of pump fibers 1 in the embodiment of the present invention is determined based on the actual power required. Generally speaking, the more pump fibers 1 there are, the more pump lasers are installed (usually one pump laser can be connected to one pump fiber 1), and the greater the power that can be provided to the system. In the embodiment of the present invention, glue is filled between the quartz tube 3 and the input signal fiber 4 to form a glue layer 6. The diameter of the quartz tube 3 is greater than the outer diameter of the input signal fiber 4. The preset length is determined based on actual conditions (the thickness of the glue layer 6). The location of the corrosion of the output signal fiber 2 and the coupling fiber 5, as well as the degree of cladding corrosion (cladding corrosion thickness), are set according to actual needs and can be determined through experiments. In addition, the purpose of fusing the output signal fiber 2 and the coupling fiber 5 to a preset fusion length and preset fusion depth is to filter out the Raman laser generated in the laser. Therefore, the preset fusion length and preset fusion depth in the embodiment of the present invention must satisfy the corresponding formula to theoretically filter out the Raman laser to the greatest extent possible. The embodiments of the present invention will be further described later and will not be elaborated on here.

[0053] In the embodiment of the present invention, the outer wall of the quartz tube 3 is roughened to destroy the total reflection structure of the outer wall of the quartz tube 3, and the high-order modes with a large numerical aperture are stripped away, thereby reducing the problem of heating of the coating layer. After the residual pump light in the laser is transmitted to the cladding of the output signal optical fiber 2, the residual pump laser is stripped away after passing through the corroded area of ​​the output signal optical fiber 2. In addition, the output signal optical fiber 2 at the corroded location and the coupling optical fiber 5 at the corroded location are fused to a preset fusion length and a preset fusion depth to achieve the purpose of filtering out the Raman laser generated in the laser.

[0054] In order to illustrate the complete solution of the embodiment of the present invention, the details of the combiner of the embodiment of the present invention are described in detail below. In order to remove the high-order mode with a large numerical aperture as much as possible and reduce the heat generation of the coating layer. The refractive index of the quartz tube 3 in the embodiment of the present invention is not less than the refractive index of the glue layer 6, and the refractive index of the glue layer 6 is not less than the refractive index of the coating layer of the input signal optical fiber 4. Theoretically, the conditions for total internal reflection are: light enters an optically sparse medium from an optically dense medium (the refractive index of the optically dense medium is large, and the refractive index of the optically sparse medium is small), and the angle of incidence is greater than or equal to the critical angle. In the combiner of the embodiment of the present invention, the refractive indices of the quartz tube 3, glue layer 6, and input signal fiber 4 decrease in order from the outside to the inside (or may be equal). During the process of injecting the pump laser from the pump fiber 1 into the input signal fiber 4, due to factors such as excessive pump fiber taper ratio or melting point scattering, some high-order modes are generated that cannot be stably transmitted in the cladding of the input signal fiber 4. These high-order modes are directly scattered into the air after passing through the roughened quartz tube 3, thereby further preventing the coating layer of the input signal fiber in the combiner of the embodiment of the present invention from absorbing excessive heat, resulting in a reduced lifespan or even damage to the coating layer of the input signal fiber 4 of the combiner of the embodiment of the present invention. It is worth noting that when filling the glue in the embodiment of the present invention, the quartz tube 3, the input signal fiber 4, and the glue layer 6 are generally coaxially arranged to prevent uneven glue layer 6 from causing local overheating of the input signal fiber 4, which would have a certain impact on the normal operation of the optical fiber combiner of the present invention.

[0055] When the other end of the output signal fiber 2 is melted with the etched area of ​​the coupling fiber 5, in order to eliminate the influence of the coupling fiber 5 and the output signal fiber 2 on the combiner as much as possible, the diameter of the etched area of ​​the output signal fiber 2 in the embodiment of the present invention is equal to the diameter of the etched area of ​​the coupling fiber 5; and the output signal fiber 2 and the coupling fiber 5 are cut from the same fiber, so as to ensure that the parameters of the output signal fiber (2) and the coupling fiber (5) are the same (parameters include core diameter, fiber model, and fiber specifications). In order to ensure that the parameters of the coupling fiber 5 and the output signal fiber 2 are exactly the same, in the actual process of manufacturing the fiber combiner of the embodiment of the present invention, two sections are usually cut from the same bundle of optical fibers, one section is used as the output signal fiber 2, and the other section is used as the coupling fiber 5, so as to ensure that the parameters of the output signal fiber 2 and the coupling fiber 5 are exactly the same.

[0056] In order to filter out the Raman laser generated in the beam combiner of the embodiment of the present invention as much as possible, the preset fusion length and preset fusion depth of the embodiment of the present invention must satisfy the corresponding formula. Specifically, the signal laser in the output signal fiber 2, the Raman laser in the output signal fiber 2, the coupling coefficient of the signal laser in the output signal fiber 2, and the coupling coefficient of the Raman laser in the output signal fiber 2 satisfy the following formula:

[0057]

[0058]

[0059]

[0060]

[0061] Wherein, λ1 represents the wavelength of the signal laser of the output signal optical fiber 2, and λ2 represents the wavelength of the Raman laser generated in the output signal optical fiber 2. represents the coupling coefficient of the signal laser, represents the coupling coefficient of the Raman laser, and Z represents the fusion length.

[0062] Among them, for the embodiment of the present invention and In the formula, λ1 and λ2 represent the subscripts of the corresponding coupling coefficients, which are related to the wavelength of the corresponding laser (i.e., different laser wavelengths correspond to different coupling coefficients). Z represents the fusion length, which can be understood as the coupling length between the coupling fiber 5 and the output signal fiber 2. Furthermore, the fusion depth also affects the coupling coefficient. Theoretically, when the above formula is satisfied, the corresponding fusion length and fusion depth of the coupling fiber 5 and the output signal fiber 2 can be calculated. In this state, the Raman laser generated by the fiber combiner of the present embodiment can be completely filtered out, and the power of the Raman laser of the coupling fiber 5 within the fiber combiner and the signal laser of the output signal fiber 2 are both at their maximum. Furthermore, the outer wall of the quartz tube 3 described in the present embodiment is typically, but not limited to, roughened by solution etching or laser micromachining. The output signal fiber 2 and the coupling fiber 5 at the etched portion are typically, but not limited to, connected by heating and melting with an oxyhydrogen flame or graphite filament.

[0063] In the embodiment of the present invention, the outer wall of the quartz tube 3 is roughened so that the total reflection structure of the outer wall of the quartz tube 3 is destroyed, and the high-order mode with a large numerical aperture is stripped off, thereby reducing the problem of heating of the coating layer; after the residual pump laser is transmitted to the cladding of the output signal optical fiber 2, the residual pump laser is stripped off after passing through the corrosion area of ​​the output signal optical fiber 2; the output signal optical fiber 2 at the corrosion site and the coupling optical fiber 5 at the corrosion site are melted to a preset fusion length and a preset melting depth to achieve the purpose of filtering out the Raman laser generated in the laser; in addition, in order to make the fiber combiner of the embodiment of the present invention The effect is better. The coupling optical fiber 5 of the optical fiber combiner of the embodiment of the present invention has the same parameters as the output signal optical fiber 2, so as to eliminate the influence of the coupling optical fiber 5 and the output signal optical fiber 2 on the optical fiber combiner of the embodiment of the present invention; the refractive index of the quartz tube 3 is not less than the refractive index of the glue layer 6, and the refractive index of the glue layer 6 is not less than the refractive index of the coating layer of the input signal optical fiber 4, further avoiding the coating layer outside the cladding of the input signal optical fiber 4 absorbing too many high-order modes and generating too much heat, thereby avoiding the problem of overheating of the coating layer of the input signal optical fiber, resulting in a reduction in the life of the coating layer or even damage.

[0064] Example 2:

[0065] Compared with the multifunctional optical fiber combiner of embodiment 1 of the present invention, embodiment 2 of the present invention further proposes a method for manufacturing the multifunctional optical fiber combiner, such as Figure 7 As shown, the multifunctional optical fiber combiner in the embodiment is manufactured, and the manufacturing method includes:

[0066] Step 201: uniformly arrange at least one pump fiber 1 on the outer wall of one end of the output signal fiber 2 to form a fiber bundle, and fuse the input signal fiber 4 to the fiber bundle to form a pump laser beam combining structure.

[0067] In the process of manufacturing the fiber combiner of the embodiment of the present invention, at least one pump fiber 1 and one end of the output signal fiber 2 are combined, fused and tapered into a fiber bundle, and the combined end is then cut flat and fused with the input signal fiber 4 at high temperature to form a pump laser beam combining structure. Alternatively, the pump fiber 1 can be pre-drawn and then attached to the output signal fiber 2 and fused together to form a pump laser beam combining structure. It is worth noting that when there are multiple pump fibers 1, the pump fibers 1 are usually evenly arranged outside the output signal fiber 2 to facilitate better tapering.

[0068] Step 202: The quartz tube 3 is sleeved onto the pump laser beam combining structure, and glue is filled and cured between the inner wall of the quartz tube 3 and the outer wall of the pump laser beam combining structure, and the outer wall of the quartz tube 3 is roughened. The glue layer 6 formed by the glue, the quartz tube 3, and the pump laser beam combining structure are coaxially arranged.

[0069] The roughening process of the quartz tube 3 in the embodiment of the present invention and the reason why the glue layer 6, the quartz tube 3 and the pump laser beam combining structure are coaxially arranged have been explained above and will not be repeated here.

[0070] Step 203: Etch the cladding at a preset distance from the other end of the output signal optical fiber 2 and at a preset position of the coupling optical fiber 5 to a preset thickness, and fuse the output signal optical fiber 2 and the coupling optical fiber 5 at the corroded location to a preset fusion length and a preset fusion depth to complete the production of the multifunctional optical fiber combiner.

[0071] At the other end of the output signal fiber 2, a portion of the coating is stripped and the cladding is etched until the cladding diameter approaches the core diameter. A section of fiber identical to the output signal fiber 2 is used as the coupling fiber 5, ensuring that the parameters of the coupling fiber 5 and the output signal fiber 2 are consistent. The same process is used to partially strip the coating and etch the cladding to the same diameter. The cladding-etched areas of the coupling fiber 5 and the output signal fiber 2 are bonded together. Heat and melt the cladding using an oxyhydrogen flame or graphite filament, slowly tapering the cladding. The fusion length and depth are controlled to ensure that the Raman laser light in the output signal fiber 2 is output from the coupling fiber 5, thereby maintaining the signal laser power in the input signal fiber 4 essentially unchanged.

[0072] In order to filter out the Raman laser light generated within the combiner of the embodiment of the present invention as much as possible, the preset fusion length and preset fusion depth of the embodiment of the present invention must satisfy corresponding formulas. While satisfying the corresponding formulas, the power of the Raman laser light of the coupling fiber 5 in the fiber combiner and the signal laser light within the output signal fiber 2 are both at maximum. Based on this, the embodiment of the present invention also includes the determination of fusing the output signal fiber 2 and the coupling fiber 5 at the corroded area to the preset fusion length and preset fusion depth, specifically comprising: laminating the output signal fiber 2 and the corroded area of ​​the coupling fiber 5, heating the laminating corroded area to a molten state, and then performing a tapering process; during the tapering process, the signal laser light and the Raman laser light are input into the fiber combiner through the input signal fiber 4, and the tapering process is stopped when the Raman laser light power within the coupling fiber 5 and the signal laser light power within the output signal fiber 2 are at maximum; wherein, when the Raman laser light power within the coupling fiber 5 and the signal laser light power within the output signal fiber 2 are at maximum, the output signal fiber 2 and the coupling fiber 5 corresponding to the corroded area are fused to the preset fusion length and preset fusion depth.

[0073] During the actual production of the optical fiber combiner of the embodiment of the present invention, the portion where the coupling optical fiber 5 and the output signal optical fiber 2 are fused during the tapering process is in a high-temperature environment, and the fusion length and fusion depth are constantly in a dynamic state. Under high-temperature conditions, it is difficult to accurately control the fusion length and fusion depth during the tapering process. As a result, the corresponding fusion length and fusion depth when the Raman laser is completely filtered out are measured by the aforementioned formula. However, it is difficult to accurately adjust the corresponding fusion length and fusion depth during the actual production of the optical fiber combiner of the embodiment of the present invention. Therefore, during the production of the optical fiber combiner of the embodiment of the present invention, based on the characteristic that the power of the Raman laser of the coupling optical fiber 5 and the signal laser in the output signal optical fiber 2 are both maximum when the Raman laser is completely filtered out, a power meter is used to monitor the power of the Raman laser and the signal laser in the output signal optical fiber 2 during the slow fusion and tapering process of the coupling optical fiber 5 and the output signal optical fiber 2. When the power meter shows that the Raman laser power in the corresponding coupling optical fiber 5 is the maximum and the signal laser power in the output signal optical fiber 2 is the maximum, the tapering process is stopped, and the production of the multifunctional optical fiber combiner of the present invention is completed.

[0074] Example 3:

[0075] Next, a specific optical fiber model is selected to illustrate the fabrication of the multifunctional optical fiber combiner according to the embodiment of the present invention. It should be noted that the multifunctional combiner according to the embodiment of the present invention is not limited to the models and parameters of the corresponding components selected in Example 3.

[0076] Six 105 / 125 numerical aperture (NA) 0.22 pump fibers 1 and a single 14 / 250 numerical aperture (NA) 0.065 output signal fiber 2 were selected for bundle assembly and tapered into a fiber bundle with a cladding diameter of 250 μm. The bundle was then fusion-spliced ​​with an input signal fiber 4 with a core diameter of 14 / 250 μm and a numerical aperture (NA) of 0.065 to produce a pump laser combiner. The coating thickness of the input signal fiber 4 was 350 μm, the numerical aperture (NA) of the cladding and inner coating was 0.46, and the refractive index of the coating was 1.50. Glue with a refractive index of 1.52 was applied to the coating of the input signal fiber 4. Take a quartz tube 3 with an inner diameter of 380μm, an outer diameter of 500μm, and a length of 15mm. The refractive index of the quartz tube 3 is 1.52. The outer wall of the quartz tube 3 is roughened by etching or laser processing. The roughened quartz tube 3 is placed on the high-refractive glue coating and the glue is cured. A 5cm section of the coating is stripped from the output signal optical fiber 2, and the remaining cladding is etched to a thickness of 25μm. Take another 14 / 250 signal optical fiber with the same parameters, and similarly strip 5cm of the coating and etch the cladding to 25 microns. The cladding corrosion areas of the two optical fibers are bonded together, and the bonded area is heated to a molten state in a high-temperature hydrogen-oxygen flame or graphite filament environment and slightly tapered. During the tapering process, a signal laser with a wavelength of 1080nm and a Raman laser with a wavelength of 1130nm are injected into the input signal fiber 4, and the output power in the coupling fiber 5 and the output signal fiber 2 is observed. The tapering is stopped when the power of the Raman laser with a wavelength of 1130nm in the coupling fiber 5 is maximized and the power of the 1080nm signal in the output signal fiber is maximized, thus completing the manufacture of the multifunctional optical fiber combiner of the present invention.

[0077] Combined with the function of the multifunctional fiber combiner described in this embodiment, the 915nm pump laser enters the inner cladding of the input signal fiber 4 through the 105 / 125 optical fiber. When some high-order modes pass through the coating of the input signal fiber, they will pass through the coating and enter the corroded quartz tube 3 due to the numerical aperture (NA) greater than 0.46. In the roughened structure of the outer wall of the corroded quartz tube 3, the total reflection is destroyed, and the high-order modes with large numerical aperture (NA) are stripped off, reducing the problem of coating heating. On the other hand, when the residual pump light in the output signal fiber 2 in the laser passes through the fusion point of the output signal fiber 2 and the coupling fiber 5, the residual pump laser is filtered out due to the corrosion of the cladding in the output signal fiber 2. At the same time, the 1130nm Raman laser in the core of the output signal fiber 2 is guided through the output signal fiber 2 and coupled to the coupling fiber 5, while the 1080nm signal laser continues to propagate along the output signal fiber 2.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multifunctional optical fiber combiner, characterized in that: The device comprises at least one pump optical fiber (1), an output signal optical fiber (2), a quartz tube (3), an input signal optical fiber (4), and a coupling optical fiber (5); The pump fiber (1) is arranged on the outer wall of one end of the output signal fiber (2), and the end of the fiber bundle formed by the pump fiber (1) and the output signal fiber (2) is connected to the end of the input signal fiber (4) to facilitate the combination of the fiber pump signal; The inner diameter of the quartz tube (3) is larger than the outer diameter of the input signal optical fiber (4), the quartz tube (3) is sleeved on the input signal optical fiber (4), and a glue layer (6) is filled between the inner wall of the quartz tube (3) and the outer wall of the input signal optical fiber (4), and the outer wall of the quartz tube (3) is roughened. When a high-order mode is transmitted to the outer wall of the quartz tube (3), it is scattered by the roughened outer wall of the quartz tube (3), so as to avoid the high-order mode causing the coating layer of the input signal optical fiber (4) to heat up; The cladding of the output signal optical fiber (2) at a preset length from the other end is etched to a preset thickness, the cladding at a preset distance from one end of the coupling optical fiber (5) is etched to a preset thickness, and the output signal optical fiber (2) at the etched location and the coupling optical fiber (5) at the etched location are melted to a preset fusion length and a preset fusion depth, so as to filter out the Raman laser generated by the laser; The refractive index of the quartz tube (3) is not less than the refractive index of the glue layer (6), and the refractive index of the glue layer (6) is not less than the refractive index of the coating layer of the input signal optical fiber (4); The coupling coefficient of the signal laser in the output signal optical fiber (2) in the melting zone and the coupling coefficient of the Raman laser in the output signal optical fiber (2) in the melting zone satisfy the following formula: in, represents the wavelength of the signal laser of the output signal optical fiber (2), represents the wavelength of the Raman laser of the output signal optical fiber (2), represents the coupling coefficient of the signal laser in the melting zone, represents the coupling coefficient of the Raman laser in the melting zone, Indicates the fusion length.

2. The multifunctional optical fiber combiner according to claim 1, characterized in that: The quartz tube (3), the input signal optical fiber (4) and the glue layer (6) are coaxially arranged.

3. The multifunctional fiber combiner according to claim 1, wherein: The diameter of the corroded portion of the output signal optical fiber (2) is equal to the diameter of the corroded portion of the coupling optical fiber (5).

4. The multifunctional fiber combiner according to claim 1, characterized in that: The output signal optical fiber (2) and the coupling optical fiber (5) are cut from the same optical fiber, so as to ensure that the parameters of the output signal optical fiber (2) and the coupling optical fiber (5) are the same.

5. The multifunctional optical fiber combiner according to claim 1, characterized in that: The outer wall of the quartz tube (3) is roughened by solution etching or laser micromachining.

6. The multifunctional optical fiber combiner according to claim 1, characterized in that: The output signal optical fiber (2) at the corroded portion and the coupling optical fiber (5) at the corroded portion are connected by heating and melting through an oxyhydrogen flame or graphite filament.

7. A method for manufacturing a multifunctional optical fiber combiner, characterized in that: include: At least one pump optical fiber (1) is evenly arranged on the outer wall side of one end of the output signal optical fiber (2) to form an optical fiber bundle, and the input signal optical fiber (4) is fused with the optical fiber bundle to form a pump laser beam combining structure; The quartz tube (3) is sleeved on the pump laser beam combining structure, and glue is filled and solidified between the inner wall of the quartz tube (3) and the outer wall of the pump laser beam combining structure, and the outer wall of the quartz tube (3) is roughened, wherein the glue layer (6) formed by the glue, the quartz tube (3) and the pump laser beam combining structure are coaxially arranged; Etching the cladding at a preset distance from the other end of the output signal optical fiber (2) and at a preset position of the coupling optical fiber (5) to a preset thickness, and fusing the output signal optical fiber (2) at the etched location and the coupling optical fiber (5) at the etched location to a preset fusion length and a preset fusion depth, thereby completing the manufacture of the multifunctional optical fiber combiner; The method further includes the step of fusing the output signal optical fiber (2) at the corroded portion and the coupling optical fiber (5) at the corroded portion to a preset fusion length and a preset fusion depth, specifically comprising: laminating the corroded portion of the output signal optical fiber (2) and the coupling optical fiber (5), heating the laminating corroded portion to a molten state, and then performing a taper process; During the taper pulling process, the signal laser and the Raman laser are input into the optical fiber combiner through the input signal optical fiber (4), and the taper pulling is stopped when the Raman laser power in the coupling optical fiber (5) and the signal laser power in the output signal optical fiber (2) are maximum; When the Raman laser power in the coupling optical fiber (5) and the signal laser power in the output signal optical fiber (2) are maximum, the output signal optical fiber (2) corresponding to the corroded portion and the coupling optical fiber (5) at the corroded portion are fused to a preset fusion length and a preset fusion depth; The coupling coefficient of the signal laser in the output signal optical fiber (2) in the melting zone and the coupling coefficient of the Raman laser in the output signal optical fiber (2) in the melting zone satisfy the following formula: in, represents the wavelength of the signal laser of the output signal optical fiber (2), represents the wavelength of the Raman laser of the output signal optical fiber (2), represents the coupling coefficient of the signal laser in the melting zone, represents the coupling coefficient of the Raman laser in the melting zone, Indicates the fusion length.

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