Atypical MOPA fiber laser device integration device, system and method

Abstract

The invention provides an atypical MOPA fiber laser device integration device, system and method. The device comprises an optical resonant cavity, a first device group and a second device group, wherein the first device group comprises a first amplification stage gain optical fiber, a first reverse pumping beam combiner, a first pumping source and a first cladding light stripper, and the second device group comprises a second amplification stage gain optical fiber, a second reverse pumping beam combiner, a second pumping source and a second cladding light stripper; the optical resonant cavity is used for receiving the pump light transmitted by the first amplification stage gain optical fiber and the second amplification stage gain optical fiber, transmitting the pump light which is not absorbed to the second amplification stage gain optical fiber and the first amplification stage gain optical fiber, and generating signal light under the action of the absorbed pump light; and the signal light is transmitted to the first amplification stage gain fiber and the second amplification stage gain fiber in positive and negative directions. The device number and the manufacturing cost are remarkably reduced, the light-to-light conversion efficiency and the system reliability are improved, and meanwhile high-power beam combination and miniaturization integration are facilitated.

Description

Technical Field

[0001] This invention relates to the field of fiber lasers, and more specifically, to an integrated device, system, and method for atypical MOPA fiber laser devices. Background Technology The basic structures of current high-power fiber lasers are mainly divided into two categories: one is the fiber oscillator structure, and the other is the master oscillator-power amplifier (MOPA) structure.

[0002] The fiber optic oscillator structure consists of a pump source, a fiber pump combiner, a fiber grating, a gain fiber, a cladding optical filter, and a fiber end cap. The pump light output from the pump source is combined by the fiber pump combiner and then injected into the gain fiber through the fiber grating. Under the action of the optical resonant cavity formed by the two fiber gratings, laser light is generated within the gain fiber. This laser light is output through a low-reflection grating, and after passing through the cladding optical filter to remove cladding light or higher-order modes, the laser light is finally output from the fiber end cap.

[0003] The MOPA structure uses an optical fiber oscillator as a seed source, which is then used in conjunction with a subsequent optical fiber amplifier to amplify the signal power. The optical fiber amplifier typically consists of a pump source, an optical fiber combiner, a gain fiber, and a cladding stripper. In the MOPA structure, the signal light generated by the optical fiber oscillator and filtered by the cladding is injected into the optical fiber amplifier. The laser beam undergoes secondary amplification in the amplifier, is then processed again by the cladding filter, and finally output from the fiber end cap. By separating the oscillation and amplification functions, the MOPA structure can achieve high output power while maintaining good beam quality.

[0004] However, both of these structures have their own technical bottlenecks. While the MOPA structure boasts advantages such as high power and high beam quality, its operation relies on the stable output of the seed light source. If the fiber amplifier is activated without a signal light injection (i.e., without a seed light source), it can easily lead to overheating or damage of the gain fiber within the amplifier. Furthermore, as the output power of the MOPA fiber laser, especially the power density within the fiber core, increases, nonlinear effects become more pronounced, primarily manifested as stimulated Raman scattering (SRS) and transverse mode instability (TMI), causing unstable operation of the fiber laser and, in severe cases, even device burnout. While existing technologies have attempted to mitigate nonlinearity issues by increasing the core diameter, reducing fiber length, employing bidirectional pumping, and optimizing the winding structure, these methods also introduce new problems such as increased modes, decreased beam quality, and reduced conversion efficiency.

[0005] Specifically, increasing the fiber core diameter and reducing the fiber length can effectively reduce the stimulated Raman effect, while using bidirectional pumping and reducing the bending radius of the gain fiber coil can significantly improve the TMI threshold, thereby further increasing the output power. However, increasing the fiber core diameter will lead to an increase in laser modes and a deterioration in beam quality; while reducing the fiber length and coil radius will reduce the optical-to-optical conversion efficiency of the laser.

[0006] In addition, fiber lasers with MOPA structures generally suffer from power ramp-up problems, with ramp-up delays ranging from milliseconds to several seconds, which seriously affect the stability of power output after the laser is started.

[0007] To address the aforementioned problems in current high-power fiber lasers, existing technologies have proposed improved schemes for "dual-ended output fiber lasers and multimode bundled fiber lasers" (see patent CN114583539A for details). These technologies are based on either a dual-cavity structure or a dual-MOPA structure, and improve pump light utilization efficiency by cascading two highly reflective gratings to recover opposing pump light. Specific solutions include: Scheme 1 uses two traditional fiber oscillator structures to form a dual-output fiber laser, connecting two high-reflectivity gratings to recover the transmitted pump light from the opposing optical resonators. The transmitted pump light, to some extent, acts as a positive pump, which can reduce some nonlinear effects and improve the overall output power. Scheme 2 uses two traditional MOPA structures to form a dual-output fiber laser, connecting two high-reflectivity gratings to recover the transmitted pump light from the opposing optical resonators, thus improving the overall output power. Scheme 3 is a simplification of Scheme 1, where the two optical resonators share the same high-reflectivity grating.

[0008] This existing technology achieves dual-ended output of two typical oscillators or two typical MOPA structures by sharing a high-reflectivity grating. Although it recovers the pump light from the opposing laser to some extent, it still has the following shortcomings: 1. The structure is relatively complex, with a large number of components, and it does not deviate from the traditional oscillating cavity and MOPA laser structure layout. Its dual-oscillating cavity scheme uses two sets of active optical fibers and two pairs of high-low reflection gratings; its dual-MOPA structure scheme requires four sets of active optical fibers, four beam combiners, four cladding strippers, and two pairs of high-low reflection gratings. 2. High cost: Due to the use of traditional simple and cumulative structures, more optical components are used, resulting in higher material and labor costs.

[0009] 3. Although a high-reflectivity grating pump light recovery scheme is partially adopted, the cladding light stripper between the seed and amplification in its MOPA structure still consumes the pump light transmitted from the fiber amplifier, resulting in waste. The optical-to-optical conversion efficiency needs to be further improved.

[0010] 4. Its dual MOPA structure still has the fatal flaw of a typical MOPA structure, namely, the amplification stage must be inserted under the premise of light output from the seed light source, otherwise the gain fiber of the amplification stage will be damaged.

[0011] Therefore, there is an urgent need for a fiber laser structure that is simpler, has higher pump light utilization, higher nonlinear threshold, and can avoid the "seed dependence" of the traditional MOPA structure. Summary of the Invention

[0012] To address the problems of complex structure, low pump light utilization, severe nonlinear effects, and strong dependence on seed light source in existing high-power fiber lasers, this invention provides an atypical MOPA fiber laser device integration device, system, and method that integrates oscillation and amplification functions. By connecting the first amplification stage gain fiber, the optical resonant cavity active fiber, and the second amplification stage gain fiber in series to form a continuous optical path, a three-segment pump absorption structure is formed, achieving efficient multi-segment utilization of pump light.

[0013] Unlike traditional MOPA structures, this invention significantly reduces dependence on seed light source stability by constructing an architecture of "oscillator-like + atypical amplifier," effectively avoiding the fiber damage risk caused by "only opening the amplifier without opening the seed light." Simultaneously, the synergistic absorption of pump light in the three gain regions significantly improves pump energy conversion efficiency, helps reduce the nonlinear effect threshold, and enhances overall system stability and output power.

[0014] Furthermore, this invention can also integrate multiple functional segments in a single optical fiber and form a resonant cavity by etching a reflective grating inside the optical fiber, making the device structure more compact, reducing the number of components, and lowering the manufacturing cost, thus having significant engineering application value.

[0015] In a first aspect, the present invention provides an integrated device for an atypical MOPA fiber laser, characterized in that the device comprises: an optical resonant cavity, a first device group, and a second device group, wherein the first device group comprises a first amplification stage gain fiber, a first reverse pump combiner, a first pump source, and a first cladding optical stripper, and the second device group comprises a second amplification stage gain fiber, a second reverse pump combiner, a second pump source, and a second cladding optical stripper; wherein The first pump source and the second pump source are used to provide pump light, respectively; The first reverse pump combiner and the second reverse pump combiner are respectively used to receive the pump light output from the first pump source and the second pump source, and to couple and inject the pump light into the first amplification stage gain fiber and the second amplification stage gain fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are respectively connected to the first reverse pump combiner and the second reverse pump combiner to receive the pump light and absorb it, while transmitting the unabsorbed pump light to the optical resonant cavity. The optical resonant cavity is used to receive pump light transmitted from the first amplification stage gain fiber and the second amplification stage gain fiber, and at the same time transmit the unabsorbed pump light to the second amplification stage gain fiber and the first amplification stage gain fiber, and generate signal light under the action of the pump light absorbed therein, and transmit the signal light bidirectionally to the first amplification stage gain fiber and the second amplification stage gain fiber. The first amplification stage gain fiber and the second amplification stage gain fiber are also used to receive the signal light and the pump light from the optical resonant cavity, and to amplify the signal light by using the pump light absorbed by them, and output the amplified signal light to the first reverse pump combiner and the second reverse pump combiner respectively. The first reverse pump combiner and the second reverse pump combiner are also used to transmit the amplified signal light to the first cladding light stripper and the second cladding light stripper, respectively. The first cladding light stripper and the second cladding light stripper are used to filter out the cladding light in the amplified signal light.

[0016] Secondly, the present invention also provides an atypical MOPA pulsed fiber laser system, characterized in that the laser system comprises: a signal combiner, a third cladding optical stripper, a third output cap, and at least one device according to any one of claims 1-8; wherein The signal combiner is connected to the first cladding light stripper and the second cladding light stripper in the device, and is used to combine the filtered amplified signal light and output the combined signal light to the third cladding light stripper. The third cladding light stripper is used to filter out the cladding light in the combined signal light; The third output cap is used to output the filtered combined signal light.

[0017] Thirdly, the present invention also provides a method for integrating atypical MOPA fiber laser devices, characterized in that the atypical MOPA fiber laser device integration device includes: an optical resonant cavity, a first device group and a second device group, wherein the first device group includes a first amplification stage gain fiber, a first reverse pump combiner, a first pump source and a first cladding light stripper, and the second device group includes a second amplification stage gain fiber, a second reverse pump combiner, a second pump source and a second cladding light stripper; The method includes: The first pump source and the second pump source each provide pump light; The first reverse pump combiner and the second reverse pump combiner respectively receive the pump light output from the first pump source and the second pump source, and couple the pump light into the first amplification stage gain fiber and the second amplification stage gain fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are respectively connected to the first reverse pump combiner and the second reverse pump combiner to receive the pump light and absorb it, while transmitting the unabsorbed pump light to the optical resonant cavity. The optical resonant cavity receives pump light transmitted from the first amplification stage gain fiber and the second amplification stage gain fiber, and simultaneously transmits unabsorbed pump light to the second amplification stage gain fiber and the first amplification stage gain fiber, and generates signal light under the action of the pump light it absorbs, and transmits the signal light bidirectionally to the first amplification stage gain fiber and the second amplification stage gain fiber. The first amplification stage gain fiber and the second amplification stage gain fiber receive the signal light and the pump light from the optical resonant cavity, and amplify the signal light by using the pump light they absorb, and output the amplified signal light to the first reverse pump combiner and the second reverse pump combiner, respectively. The first reverse pump combiner and the second reverse pump combiner transmit the amplified signal light to the first cladding light stripper and the second cladding light stripper, respectively. The first cladding light stripper and the second cladding light stripper respectively filter out the cladding light in the amplified signal light.

[0018] Fourthly, the present invention also provides a method for implementing an atypical MOPA pulsed fiber laser, characterized in that the atypical MOPA pulsed fiber laser system includes: a signal combiner, a third cladding light stripper, a third output cap, and at least one device corresponding to the method of any one of claims 11-18. The method includes: The signal combiner is connected to the first cladding light stripper and the second cladding light stripper in the device, and combines the filtered amplified signal light and outputs the combined signal light to the third cladding light stripper. The third cladding light stripper filters out the cladding light in the combined signal light; The third output cap outputs the filtered combined signal light.

[0019] The atypical MOPA fiber laser device integration device, system, and method provided by this invention have the following significant advantages compared to existing technologies: First, the structure is simple and the number of components is greatly reduced. While retaining the advantages of dual-end output of fiber lasers, this invention integrates the first amplification stage gain fiber, the optical resonator active fiber, and the second amplification stage gain fiber into a "three-segment pump absorption structure" in the form of a continuous optical path. This merges the original two typical oscillating cavity or MOPA structures into a single structure, thereby simplifying the system layout. The number of optical components in the whole machine is reduced from 22 to 13, and the number of main line fusion points is reduced from 17 to 11, significantly reducing the structural complexity.

[0020] Secondly, it boasts low manufacturing costs and high production efficiency. Due to the significant reduction in components and welding points, fewer optical components are required, resulting in a more compact component layout. This effectively reduces material costs and production time, while also lowering the tolerance for errors during assembly and improving manufacturing efficiency.

[0021] Third, the pump light utilization efficiency is high, improving the optical-to-optical conversion efficiency. Three sets of active optical fibers work together to form a continuous optical path, participating in the absorption and conversion of bidirectional six-segment pump light. This allows the pump light to be effectively absorbed multiple times in multiple quantum conversion regions, avoiding waste and greatly improving the pump light utilization rate and overall optical-to-optical conversion efficiency.

[0022] Fourth, it offers high reliability and optimized thermal management. It reduces the risk of failure caused by the number of components and fusion splices. Simultaneously, pump absorption is distributed across multiple fiber segments, avoiding single-point heat accumulation and effectively reducing the thermal load on the gain fiber, especially the fusion splice area, thereby improving the laser's operational stability and lifespan. Furthermore, the multi-quantum conversion region structure formed by the three active fiber segments effectively distributes the quantum conversion pressure, reducing the thermal effects in the conversion section and further enhancing thermal management capabilities.

[0023] Fifth, the size can be further reduced, which is beneficial for system integration. Fewer optical components and a simpler layout provide space for the miniaturization of the laser, making it easier to achieve compact system integration and facilitating the modularization, portable packaging, and mass production of subsequent products. In addition, thanks to the ability to achieve dual-output by sharing a single resonant cavity, this invention retains the advantages of dual-end output while avoiding the duplication of cooling and control systems caused by the dual-oscillator configuration in traditional structures, further reducing the overall size, system weight, and overall cost.

[0024] Sixth, it offers stronger nonlinear effect suppression and more stable output. The dual-end output structure ensures uniform laser power distribution within the cavity, reducing the peak power density and improving nonlinear thresholds such as TMI (transverse mode instability) and SRS (stimulated Raman scattering). Although the overall cavity length increases slightly, potentially leading to a decrease in the SRS threshold, this can be effectively compensated for by adjusting parameters such as the core size of the active fiber, the numerical aperture, and the reflectivity of the reflection grating, ensuring stable system operation.

[0025] Seventh, it overcomes the "seed dependence" defect of traditional MOPA. Because this invention has the characteristics of an oscillating cavity, it can start autonomously and no longer depends on an external seed light source. This avoids the problem of gain fiber damage caused by "only opening the large light source without opening the seed light source", thus improving operational safety and system fault tolerance.

[0026] Eighth, high beam combining consistency and low debugging difficulty. The present invention adopts a single-cavity dual-end output structure, which naturally ensures the consistency of the two output lasers in terms of frequency, phase and modulation characteristics. Compared with the traditional "dual-machine beam combining" scheme, it greatly simplifies the debugging requirements of the beam combining system, avoids complex phase-locking or temperature control processes, and improves beam combining efficiency and stability, which is especially suitable for high-power parallel processing scenarios.

[0027] Ninth, it boasts strong application expansion capabilities and broad industrial prospects. While simplifying its structure, the dual-output laser of this invention retains and enhances the advantages of dual-output, enabling higher power output through beam combining and supporting high-power parallel processing. It is particularly suitable for high-power scenarios such as industrial processing, material handling, laser welding, and 3D printing, possessing excellent application scalability and commercial value. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, 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 these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of an atypical MOPA fiber laser device integration device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of a MOPA pulsed fiber laser system, including an atypical MOPA fiber laser device integration device, provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of a MOPA pulsed fiber laser system, which includes multiple atypical MOPA fiber laser device integration devices, provided in an embodiment of the present invention. Detailed Implementation

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Invention Overview As mentioned above, the present invention provides a highly centralized atypical MOPA fiber laser device integration device, system and method, which significantly reduces the number of devices and manufacturing costs, improves optical-to-optical conversion efficiency and system reliability, and facilitates high-power beam combining and miniaturized integration.

[0032] Exemplary device Figure 1 This is a schematic diagram of an atypical MOPA fiber laser device integration device provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the device 100 provided in this embodiment includes: An optical resonant cavity, a first device group, and a second device group. The first device group includes a first amplification stage gain fiber 4, a first reverse pump combiner 3, a first pump source 12, and a first cladding optical stripper 2. The second device group includes a second amplification stage gain fiber 6, a second reverse pump combiner 9, a second pump source 13, and a second cladding optical stripper 10.

[0033] The device parameters of the first and second device groups are independent of each other. Based on achieving dual-end output, this invention allows the two amplification channels to be configured with the same or different parameters according to different application requirements, providing greater system flexibility and adaptability. Independent parameter settings not only enhance the application coverage of fiber lasers in multiple scenarios but also facilitate differentiated customized development.

[0034] When the parameters of the first and second device groups are set to be the same, the output beams from the two channels can be highly consistent in terms of power, spectrum, and mode characteristics. This is beneficial for applications requiring high beam consistency, such as beam combining, interferometric processing, and high-power parallel processing. For example, in high-power laser welding, laser cladding, or 3D printing, having identical parameters for the two output channels helps improve processing efficiency and consistency.

[0035] When the two sets of parameters are set differently, it is suitable for applications requiring dual-wavelength output, different power channel output, or special beam characteristic combination output. For example, it can be used for simultaneous roughing and finishing, or for applying lasers of different wavelengths or powers to different materials in multi-material processing, so as to achieve more precise process control and higher energy efficiency.

[0036] The device parameters include, but are not limited to, the output wavelength of the pump source, the output power of the pump source, the mode type of the pump light, the length of the gain fiber, the doping concentration of the gain fiber, the core diameter and cladding diameter of the gain fiber, the numerical aperture (NA) of the gain fiber, the coupling efficiency of the reverse pump combiner, the wavelength range applicable to the reverse pump combiner, and the stripping efficiency of the cladding stripper. By combining and configuring these parameters, comprehensive control can be achieved over the pump light absorption efficiency, signal light amplification uniformity, output stability, and nonlinear suppression capability in the amplification path, further improving the overall optical-to-optical conversion efficiency, operational reliability, and application scalability of the system. This independent parameter configuration also facilitates later debugging, maintenance, or upgrades, contributing to the development of customized, modular, and serialized products.

[0037] The first pump source 12 and the second pump source 13 are used to provide pump light, respectively.

[0038] The output wavelengths of the first pump source 12 and the second pump source 13 are 915nm, 940nm, 960nm, 965nm, 970nm, 976nm or 985nm.

[0039] The first pump source 12 and the second pump source 13 can be flexibly controlled in terms of activation mode and parameter adjustment according to actual application requirements. The two pump sources can be activated simultaneously to achieve symmetrical drive, maximum output power and high-efficiency operation; or, under specific operating conditions, only one set of pump sources can be activated to simplify the control strategy or adapt to different power level operating modes.

[0040] The first reverse pump combiner 3 and the second reverse pump combiner 9 are respectively used to receive the pump light output from the first pump source 12 and the second pump source 13, and to couple and inject the pump light into the first amplification stage gain fiber 4 and the second amplification stage gain fiber 6.

[0041] The reverse pumping structure effectively improves the distribution of pump light in the optical fiber and extends the interaction length between the pump light and the signal light, thereby enhancing the pump light absorption efficiency and laser amplification efficiency. Compared with the traditional unidirectional pumping method, this structure has higher gain uniformity and thermal load distribution stability, effectively reducing the risk of nonlinear effects during high-power operation and improving overall performance and reliability.

[0042] The first amplification stage gain fiber 4 and the second amplification stage gain fiber 6 are active fibers, which are connected to the first reverse pump combiner 3 and the second reverse pump combiner 9, respectively, to receive and absorb the pump light, and at the same time transmit the unabsorbed pump light (i.e. the pump light transmitted from the first amplification stage gain fiber 4 and the second amplification stage gain fiber 6) to the optical resonant cavity, thereby realizing the deep utilization of pump light energy and improving the overall pump efficiency.

[0043] The optical resonant cavity comprises an active optical fiber 5 and two reflective gratings 7 and 8 disposed at both ends of the active optical fiber 5. It receives pump light transmitted from the first amplification stage gain fiber 4 and the second amplification stage gain fiber 6, and simultaneously transmits unabsorbed pump light to the second amplification stage gain fiber 6 and the first amplification stage gain fiber 4. Under the action of the absorbed pump light, it generates signal light, which is then transmitted bidirectionally to the first amplification stage gain fiber 4 and the second amplification stage gain fiber 6. The reflectivity of the two reflective gratings 7 and 8 of the optical resonant cavity is set to any value between 5% and 95% according to actual requirements.

[0044] Unlike existing MOPA structures, the optical resonant cavity in this invention consists of an independent active optical fiber and reflective gratings 7 and 8 at its two ends, forming a closed optical feedback path. This structure itself possesses laser oscillation initiation capability, generating signal light after absorbing pump light and feeding it back and forth within the cavity to form laser oscillation. This structure is fundamentally different from the MOPA system that relies on an external seed light source. The optical resonant cavity forms an independent closed feedback path, coupled with the gain fibers on both sides to form an overall oscillation amplification system, realizing a complete laser functional module from pump absorption, laser oscillation initiation to signal light output. This structure can both self-oscillate and output laser light, and also work with the amplification sections on both sides to increase the output power. In summary, this invention adopts a cavity-like structure to achieve autonomous laser output initiation, without relying on an external seed light source, avoiding the damage to the gain fiber caused by "only opening the amplification without the seed light," and improving operational safety and fault tolerance.

[0045] The first amplification stage gain fiber 4 and the second amplification stage gain fiber 6 not only serve as the primary absorption section of the pump light, but also amplify the signal light. They are also used to receive the signal light and the pump light from the optical resonant cavity, and to amplify the signal light using the absorbed pump light (which includes pump light transmitted from the reverse pump combiner and unabsorbed pump light transmitted from the optical resonant cavity), outputting the amplified signal light to the first reverse pump combiner 3 and the second reverse pump combiner 9, respectively.

[0046] The length, doping concentration, core diameter, cladding diameter, and numerical aperture of the first amplification stage gain fiber 4, the second amplification stage gain fiber 6, and the active fiber in the optical resonant cavity are set according to actual requirements (such as required output power, pump light power density, nonlinear threshold control requirements, etc.). Typically, in medium-to-high power scenarios, to prevent fiber nonlinear effects (such as stimulated Raman scattering (SRS) or transverse mode instability (TMI), the core diameter can be appropriately increased and the fiber length extended to dilute the power density; while in applications with high requirements for compactness and beam quality, relatively short fibers with smaller core diameters can be selected to achieve high-quality near-single-mode output.

[0047] The first amplification stage gain fiber 4, the second amplification stage gain fiber 6, and the active fiber in the optical resonant cavity form a continuous optical path. These three components work together to absorb pump light, forming a three-segment pump absorption structure. This merges the original two MOPA structures into a single structure, significantly reducing the number of components and greatly lowering structural complexity. Unlike existing MOPA structures, the optical resonant cavity not only absorbs energy but also serves as the core of the entire laser system's oscillation, forming an independent oscillation cavity with self-feedback and self-laser output capabilities. Together with the amplification sections on both sides, it constitutes an atypical MOPA structure.

[0048] Furthermore, this structure utilizes three sets of active optical fibers to form a continuous optical path, participating in bidirectional six-segment pump light absorption. This achieves multi-segment distributed absorption of the pump light, significantly improving the utilization efficiency of the pump light and the overall optical-to-optical conversion efficiency, while avoiding pump light waste caused by single-segment fiber overload. Simultaneously, multi-segment absorption effectively distributes the thermal load in the optical fiber, reducing the risk of localized heating and related thermal damage, and enhancing the system's thermal stability and operational reliability.

[0049] The three-stage pump absorption structure can also be integrated into the same optical fiber, that is, the first amplification stage gain fiber 4, the second amplification stage gain fiber 6, and the central optical resonator are fabricated using the same doped fiber, avoiding fusion splicing at intermediate connection points, thereby improving system stability and assembly consistency. The two reflection gratings 7 and 8 of the optical resonator can be directly inscribed on the integrated same fiber. This integrated structure not only reduces the number of optical components and fusion points, resulting in a compact device layout, lower material costs and production time, improved manufacturing efficiency, and simplified assembly tolerance, but also facilitates modular product packaging, contributing to improved mass production consistency and beam quality control capabilities. The single resonator with dual-ended output avoids duplication of cooling and control systems for dual oscillators, further reducing the overall size and weight of the device.

[0050] The dual-end output structure uniformly distributes power, reducing peak power density and improving TMI and SRS thresholds. Adjustments to parameters such as the active fiber core size, numerical aperture, and reflectivity of the reflection grating effectively compensate for changes in nonlinear effect thresholds, ensuring stable output. Although this invention significantly improves pump light absorption efficiency and overall optical-to-optical conversion efficiency through a three-segment continuous pump structure, the introduction of a shared optical resonator increases the overall cavity length compared to traditional MOPA structures, potentially leading to a decrease in the threshold for nonlinear effects such as stimulated Raman scattering (SRS). To address this, optimization schemes can be adopted in the active fiber design and reflection grating matching. For example, by controlling the active fiber length, numerical aperture, and doping concentration, and adjusting the reflectivity and spectral width of reflection gratings 7 and 8, intracavity gain equalization and power density control can be achieved, effectively compensating for the nonlinear risks that may arise from the increased cavity length and ensuring the stability and reliability of the system at high power.

[0051] The first reverse pump combiner 3 and the second reverse pump combiner 9 are also used to transmit the amplified signal light to the first cladding light stripper 2 and the second cladding light stripper 10, respectively.

[0052] The first cladding light stripper 2 and the second cladding light stripper 10 are used to filter out the cladding light in the amplified signal light to prevent optical loss and potential system instability caused by the cladding light.

[0053] The first device group may further include a first output cap 1, and the second device group may further include a second output cap 11. The first output cap 1 and the second output cap 11 are respectively connected to the first cladding light stripper 2 and the second cladding light stripper 10, and are used to output the filtered amplified signal light.

[0054] Exemplary System Accordingly, embodiments of the present invention also provide a MOPA pulsed fiber laser system, such as... Figure 2 As shown, a schematic diagram of a MOPA pulsed fiber laser system including an atypical MOPA fiber laser device integration device is illustrated; as shown Figure 3 As shown, a schematic diagram of a MOPA pulsed fiber laser system is presented, which includes an integrated device of multiple atypical MOPA fiber laser devices.

[0055] The laser system includes: Signal combiner 13, third cladding optical stripper 14, third output cap 15, and at least one atypical MOPA fiber laser device integrated device 100; wherein The signal combiner 13 is connected to the first cladding light stripper 2 and the second cladding light stripper 10 in the device 100, and is used to combine the filtered amplified signal light and output the combined signal light to the third cladding light stripper 14. The third cladding light stripper 14 is used to filter out the cladding light in the combined signal light; The third output cap 15 is used to output the filtered combined signal light.

[0056] Compared to the traditional method of combining two independent lasers, the device 100 in this invention adopts a dual-end output structure with a single common optical resonant cavity, which can easily ensure that the optical frequency, phase and modulation characteristics of the two output channels are highly consistent. It does not require additional complex debugging such as frequency synchronization, temperature control adjustment or phase locking, which significantly simplifies the system beam combining process and improves beam combining efficiency and stability. It is especially suitable for high-power industrial scenarios that require multiple beams to work in parallel.

[0057] It should be noted that although several devices, units, or modules of atypical MOPA fiber laser device integration systems have been mentioned in the detailed description above, this classification is merely exemplary and not mandatory. In fact, according to embodiments of the present invention, the features and functions of two or more modules described above can be embodied in one module. Conversely, the features and functions of one module described above can be further divided and embodied by multiple modules.

[0058] While the spirit and principles of the invention have been described with reference to several specific embodiments, it should be understood that the invention is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for ease of description. The invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0059] The present invention also provides the following solutions: 1. An integrated device for an atypical MOPA fiber laser, characterized in that the device comprises: an optical resonant cavity, a first device group, and a second device group; the first device group comprises a first amplification stage gain fiber, a first reverse pump combiner, a first pump source, and a first cladding optical stripper; the second device group comprises a second amplification stage gain fiber, a second reverse pump combiner, a second pump source, and a second cladding optical stripper; wherein... The first pump source and the second pump source are used to provide pump light, respectively; The first reverse pump combiner and the second reverse pump combiner are respectively used to receive the pump light output from the first pump source and the second pump source, and to couple and inject the pump light into the first amplification stage gain fiber and the second amplification stage gain fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are respectively connected to the first reverse pump combiner and the second reverse pump combiner to receive the pump light and absorb it, while transmitting the unabsorbed pump light to the optical resonant cavity. The optical resonant cavity is used to receive pump light transmitted from the first amplification stage gain fiber and the second amplification stage gain fiber, and at the same time transmit the unabsorbed pump light to the second amplification stage gain fiber and the first amplification stage gain fiber, and generate signal light under the action of the pump light absorbed therein, and transmit the signal light bidirectionally to the first amplification stage gain fiber and the second amplification stage gain fiber. The first amplification stage gain fiber and the second amplification stage gain fiber are also used to receive the signal light and the pump light from the optical resonant cavity, and to amplify the signal light by using the pump light absorbed by them, and output the amplified signal light to the first reverse pump combiner and the second reverse pump combiner respectively. The first reverse pump combiner and the second reverse pump combiner are also used to transmit the amplified signal light to the first cladding light stripper and the second cladding light stripper, respectively. The first cladding light stripper and the second cladding light stripper are used to filter out the cladding light in the amplified signal light.

[0060] 2. The atypical MOPA fiber laser device integration device according to item 1, characterized in that the optical resonant cavity is composed of an active optical fiber and two reflective gratings disposed at both ends of the active optical fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are active fibers.

[0061] 3. The atypical MOPA fiber laser device integration device according to item 2 is characterized in that the reflectivity of the two reflective gratings of the optical resonant cavity is set to any value between 5% and 95% according to actual needs.

[0062] 4. The atypical MOPA fiber laser device integration device according to item 2, characterized in that the length doping concentration, core diameter, cladding diameter and numerical aperture of the first amplification stage gain fiber, the second amplification stage gain fiber and the active fiber in the optical resonant cavity are set according to actual requirements.

[0063] 5. The atypical MOPA fiber laser device integration device according to item 2 is characterized in that the first amplification stage gain fiber, the second amplification stage gain fiber and the active fiber in the optical resonant cavity constitute a continuous optical path, and the three cooperate to absorb pump light to form a three-segment pump absorption structure.

[0064] 6. The atypical MOPA fiber laser device integration device according to item 5, characterized in that the three-segment pump absorption structure is integrated in the same optical fiber; The two reflective gratings of the optical resonant cavity are inscribed on the same integrated optical fiber.

[0065] 7. The atypical MOPA fiber laser device integration device according to item 1, characterized in that the device parameters of the first device group and the second device group are independent of each other and can be set to be the same or different according to actual needs; The device parameters include the output wavelength of the pump source, the output power of the pump source, the mode type of the pump light, the length of the gain fiber, the doping concentration of the gain fiber, the core diameter and cladding diameter of the gain fiber, the numerical aperture of the gain fiber, the coupling efficiency of the reverse pump combiner, the wavelength range applicable to the reverse pump combiner, and the stripping efficiency of the cladding stripper.

[0066] 8. The atypical MOPA fiber laser device integration device according to item 7, characterized in that the output wavelengths of the first pump source and the second pump source are 915nm, 940nm, 960nm, 965nm, 970nm, 976nm or 985nm.

[0067] 9. An atypical MOPA fiber laser device integration device according to any one of items 1-8, characterized in that the first device group further includes a first output cap, the second device group further includes a second output cap, the first output cap and the second output cap are respectively connected to the first cladding light stripper and the second cladding light stripper for outputting filtered amplified signal light.

[0068] 10. An atypical MOPA pulsed fiber laser system, characterized in that the laser system comprises: a signal combiner, a third cladding optical stripper, a third output cap, and at least one of the devices described in items 1-8; wherein... The signal combiner is connected to the first cladding light stripper and the second cladding light stripper in the device, and is used to combine the filtered amplified signal light and output the combined signal light to the third cladding light stripper. The third cladding light stripper is used to filter out the cladding light in the combined signal light; The third output cap is used to output the filtered combined signal light.

[0069] 11. A method for integrating atypical MOPA fiber laser devices, characterized in that the atypical MOPA fiber laser device integration device includes: an optical resonant cavity, a first device group and a second device group, wherein the first device group includes a first amplification stage gain fiber, a first reverse pump combiner, a first pump source and a first cladding optical stripper, and the second device group includes a second amplification stage gain fiber, a second reverse pump combiner, a second pump source and a second cladding optical stripper; The method includes: The first pump source and the second pump source each provide pump light; The first reverse pump combiner and the second reverse pump combiner respectively receive the pump light output from the first pump source and the second pump source, and couple the pump light into the first amplification stage gain fiber and the second amplification stage gain fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are respectively connected to the first reverse pump combiner and the second reverse pump combiner to receive the pump light and absorb it, while transmitting the unabsorbed pump light to the optical resonant cavity. The optical resonant cavity receives pump light transmitted from the first amplification stage gain fiber and the second amplification stage gain fiber, and simultaneously transmits unabsorbed pump light to the second amplification stage gain fiber and the first amplification stage gain fiber, and generates signal light under the action of the pump light it absorbs, and transmits the signal light bidirectionally to the first amplification stage gain fiber and the second amplification stage gain fiber. The first amplification stage gain fiber and the second amplification stage gain fiber receive the signal light and the pump light from the optical resonant cavity, and amplify the signal light by using the pump light they absorb, and output the amplified signal light to the first reverse pump combiner and the second reverse pump combiner, respectively. The first reverse pump combiner and the second reverse pump combiner transmit the amplified signal light to the first cladding light stripper and the second cladding light stripper, respectively. The first cladding light stripper and the second cladding light stripper respectively filter out the cladding light in the amplified signal light.

[0070] 12. The atypical MOPA fiber laser device integration method according to item 11, characterized in that the optical resonant cavity is composed of an active optical fiber and two reflective gratings disposed at both ends of the active optical fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are active fibers.

[0071] 13. The atypical MOPA fiber laser device integration method according to item 12 is characterized in that the reflectivity of the two reflective gratings of the optical resonant cavity is set to any value between 5% and 95% according to actual needs.

[0072] 14. The atypical MOPA fiber laser device integration method according to item 12, characterized in that the length doping concentration, core diameter, cladding diameter and numerical aperture of the first amplification stage gain fiber, the second amplification stage gain fiber and the active fiber in the optical resonant cavity are set according to actual requirements.

[0073] 15. The atypical MOPA fiber laser device integration method according to item 12 is characterized in that the first amplification stage gain fiber, the second amplification stage gain fiber and the active fiber in the optical resonant cavity constitute a continuous optical path, and the three cooperate to absorb pump light to form a three-segment pump absorption structure.

[0074] 16. The method for integrating atypical MOPA fiber laser devices according to item 15, characterized in that the three-segment pump absorption structure is integrated in the same fiber; The two reflective gratings of the optical resonant cavity are inscribed on the same integrated optical fiber.

[0075] 17. The atypical MOPA fiber laser device integration method according to item 11, characterized in that the device parameters of the first device group and the second device group are independent of each other and can be set to be the same or different according to actual needs; The device parameters include the output wavelength of the pump source, the output power of the pump source, the mode type of the pump light, the length of the gain fiber, the doping concentration of the gain fiber, the core diameter and cladding diameter of the gain fiber, the numerical aperture of the gain fiber, the coupling efficiency of the reverse pump combiner, the wavelength range applicable to the reverse pump combiner, and the stripping efficiency of the cladding stripper.

[0076] 18. The method for integrating atypical MOPA fiber laser devices according to item 17, characterized in that the output wavelengths of the first pump source and the second pump source are 915nm, 940nm, 960nm, 965nm, 970nm, 976nm or 985nm.

[0077] 19. The method for integrating atypical MOPA fiber laser devices according to any one of items 11-18, characterized in that the first device group further includes a first output cap, and the second device group further includes a second output cap; The method further includes: the first output cap and the second output cap are respectively connected to the first cladding light stripper and the second cladding light stripper to output the filtered amplified signal light.

[0078] 20. A method for implementing an atypical MOPA pulsed fiber laser, characterized in that the atypical MOPA pulsed fiber laser system includes: a signal combiner, a third cladding light stripper, a third output cap, and an apparatus corresponding to the method described in at least one of items 11-18; The method includes: The signal combiner is connected to the first cladding light stripper and the second cladding light stripper in the device, and combines the filtered amplified signal light and outputs the combined signal light to the third cladding light stripper. The third cladding light stripper filters out the cladding light in the combined signal light; The third output cap outputs the filtered combined signal light.

Claims

1. An integrated device for atypical MOPA fiber laser devices, characterized in that, The device includes: an optical resonant cavity, a first device group, and a second device group. The first device group includes a first amplification stage gain fiber, a first reverse pump combiner, a first pump source, and a first cladding optical stripper. The second device group includes a second amplification stage gain fiber, a second reverse pump combiner, a second pump source, and a second cladding optical stripper. The first pump source and the second pump source are used to provide pump light, respectively; The first reverse pump combiner and the second reverse pump combiner are respectively used to receive the pump light output from the first pump source and the second pump source, and to couple and inject the pump light into the first amplification stage gain fiber and the second amplification stage gain fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are respectively connected to the first reverse pump combiner and the second reverse pump combiner to receive the pump light and absorb it, while transmitting the unabsorbed pump light to the optical resonant cavity. The optical resonant cavity is used to receive pump light transmitted from the first amplification stage gain fiber and the second amplification stage gain fiber, and at the same time transmit the unabsorbed pump light to the second amplification stage gain fiber and the first amplification stage gain fiber, and generate signal light under the action of the pump light absorbed therein, and transmit the signal light bidirectionally to the first amplification stage gain fiber and the second amplification stage gain fiber. The first amplification stage gain fiber and the second amplification stage gain fiber are also used to receive the signal light and the pump light from the optical resonant cavity, and to amplify the signal light by using the pump light absorbed by them, and output the amplified signal light to the first reverse pump combiner and the second reverse pump combiner respectively. The first reverse pump combiner and the second reverse pump combiner are also used to transmit the amplified signal light to the first cladding light stripper and the second cladding light stripper, respectively. The first cladding light stripper and the second cladding light stripper are used to filter out the cladding light in the amplified signal light.

2. The atypical MOPA fiber laser device integration device according to claim 1, characterized in that, The optical resonant cavity is composed of an active optical fiber and two reflective gratings disposed at both ends of the active optical fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are active fibers.

3. The atypical MOPA fiber laser device integration device according to claim 2, characterized in that, The reflectivity of the two reflective gratings of the optical resonant cavity is set to any value between 5% and 95% according to actual needs.

4. The atypical MOPA fiber laser device integration device according to claim 2, characterized in that, The length, doping concentration, core diameter, cladding diameter, and numerical aperture of the first amplification stage gain fiber, the second amplification stage gain fiber, and the active fiber in the optical resonant cavity are set according to actual requirements.

5. An atypical MOPA pulsed fiber laser system, characterized in that, The laser system comprises: a signal beam combiner, a third cladding stripper, a third output cap, and at least one device according to any one of claims 1-4; wherein The signal combiner is connected to the first cladding light stripper and the second cladding light stripper in the device, and is used to combine the filtered amplified signal light and output the combined signal light to the third cladding light stripper. The third cladding light stripper is used to filter out the cladding light in the combined signal light; The third output cap is used to output the filtered combined signal light.

6. A method for integrating atypical MOPA fiber laser devices, characterized in that, The atypical MOPA fiber laser device integration device includes: an optical resonant cavity, a first device group and a second device group. The first device group includes a first amplification stage gain fiber, a first reverse pump combiner, a first pump source and a first cladding optical stripper. The second device group includes a second amplification stage gain fiber, a second reverse pump combiner, a second pump source and a second cladding optical stripper. The method includes: The first pump source and the second pump source each provide pump light; The first reverse pump combiner and the second reverse pump combiner respectively receive the pump light output from the first pump source and the second pump source, and couple the pump light into the first amplification stage gain fiber and the second amplification stage gain fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are respectively connected to the first reverse pump combiner and the second reverse pump combiner to receive the pump light and absorb it, while transmitting the unabsorbed pump light to the optical resonant cavity. The optical resonant cavity receives pump light transmitted from the first amplification stage gain fiber and the second amplification stage gain fiber, and simultaneously transmits unabsorbed pump light to the second amplification stage gain fiber and the first amplification stage gain fiber, and generates signal light under the action of the pump light it absorbs, and transmits the signal light bidirectionally to the first amplification stage gain fiber and the second amplification stage gain fiber. The first amplification stage gain fiber and the second amplification stage gain fiber receive the signal light and the pump light from the optical resonant cavity, and amplify the signal light by using the pump light they absorb, and output the amplified signal light to the first reverse pump combiner and the second reverse pump combiner, respectively. The first reverse pump combiner and the second reverse pump combiner transmit the amplified signal light to the first cladding light stripper and the second cladding light stripper, respectively. The first cladding light stripper and the second cladding light stripper respectively filter out the cladding light in the amplified signal light.

7. The method for integrating atypical MOPA fiber laser devices according to claim 6, characterized in that, The optical resonant cavity is composed of an active optical fiber and two reflective gratings disposed at both ends of the active optical fiber; The first amplification stage gain fiber and the second amplification stage gain fiber are active fibers.

8. The method for integrating atypical MOPA fiber laser devices according to claim 7, characterized in that, The reflectivity of the two reflective gratings of the optical resonant cavity is set to any value between 5% and 95% according to actual needs.

9. The method for integrating atypical MOPA fiber laser devices according to claim 7, characterized in that, The length, doping concentration, core diameter, cladding diameter, and numerical aperture of the first amplification stage gain fiber, the second amplification stage gain fiber, and the active fiber in the optical resonant cavity are set according to actual requirements.

10. A method for implementing an atypical MOPA pulsed fiber laser, characterized in that, The atypical MOPA pulsed fiber laser system includes: a signal combiner, a third cladding optical stripper, a third output cap, and at least one device corresponding to the method of any one of claims 6-9; The method includes: The signal combiner is connected to the first cladding light stripper and the second cladding light stripper in the device, and combines the filtered amplified signal light and outputs the combined signal light to the third cladding light stripper. The third cladding light stripper filters out the cladding light in the combined signal light; The third output cap outputs the filtered combined signal light.

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