Common-cavity laser module

Abstract

Different from the prior art, the common-cavity laser module provided by the invention is characterized in that seed signal light is firstly amplified through a first pumping assembly to generate first signal light, and then the intra-cavity field intensity of the first signal light is enhanced through an optical fiber resonance outer cavity; therefore, the pumping absorption rate of the gain medium of the optical fiber resonance inner cavity to the first signal light is effectively increased, the gain medium of the optical fiber resonance inner cavity can convert more second signal light, and finally the common-cavity laser module obtains high-power and high-stability target laser. The common-cavity laser module has a common-cavity structure, so that high-selectivity filtering of specific wavelengths can be realized, and the output power of the common-cavity laser module is increased to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber laser, and particularly relates to a common cavity laser module. Background Art

[0002] Lasers in the 2.1μm band are widely used in fields such as biomedical, plastic processing, atmospheric transmission, gas sensing, nonlinear optics, and military applications. High-frequency, high-energy density, 2.1μm laser modules can be used for the measurement of atmospheric pollutants in the air. In addition, the absorption coefficient of water in human tissues for the 2.1μm band is as high as 600 cm -1 , and the use of a 2.1μm laser module can better control the penetration depth of the laser into biological tissues and achieve good surgical hemostasis effects.

[0003] The rare earth ions used for laser output in the 2.1μm band are mainly Tm 3+ , Ho 3+ ions. For thulium-doped fiber, 2.1μm is far from the emission peak of thulium ions, so the use of thulium-doped fiber to emit 2.1μm band laser has extremely low efficiency. Holmium ions have a high emission peak at 2.1μm, but due to its absorption peak in the 1.9μm band, there is no mature commercial pump source to pump holmium ions for the time being. Currently, thulium-holmium co-doped fiber is usually used as the gain fiber in the market, and a mature 793nm semiconductor pumped active fiber is used to emit 2.1μm band laser. However, in thulium-holmium co-doped fiber, since the doping regions of thulium ions and holmium ions are the same, energy up-conversion will occur when thulium ions transfer energy to holmium ions, affecting the efficiency of thulium-holmium co-doped fiber. At the same time, thulium-holmium co-doped fiber has a high quantum loss and serious heat accumulation, which also reduces the energy level lifetime of the 3f4 energy level and similarly limits the efficiency of thulium-holmium co-doped fiber.

[0004] Therefore, there is an urgent need for a common cavity laser module to solve the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a common cavity laser module for improving the technical problem of the low output power of the existing laser module.

[0006] To solve the above technical problems, the present invention provides a common cavity laser module, including a fiber resonant outer cavity and a first cladding light filter connected in the transmission direction from the signal input end to the signal output end. The fiber resonant outer cavity sequentially includes a first high-reflection fiber grating, a first pump assembly, a fiber resonant inner cavity, and a second high-reflection fiber grating along the transmission direction; wherein, the fiber resonant outer cavity is used to enhance the intracavity field strength of the first signal light emitted by the first pump assembly, and enable the first signal light to be absorbed by the gain medium in the fiber resonant inner cavity to generate a second signal light; the fiber resonant inner cavity is used to output the second signal light after oscillation amplification.

[0007] Preferably, the first pumping component is a forward pumping structure, and the first pumping component includes a first pump source, a second pump source, a first beam combiner, and a first gain fiber; Wherein, the first input end of the first beam combiner is connected to the first pump source, the second input end of the first beam combiner is connected to the reflection end of the first high reflection fiber grating, and the third input end of the first beam combiner is connected to the second pump source; the output end of the first beam combiner is fusion spliced to the first end of the first gain fiber.

[0008] Preferably, the fiber resonant cavity includes a third high reflection fiber grating, a second gain fiber, and a low reflection fiber grating in sequence along the transmission direction, and the output end of the low reflection fiber grating is connected to the input end of the first cladding light filter.

[0009] Preferably, the common cavity laser module further includes a second cladding light filter, the input end of the second cladding light filter is fusion spliced to the second end of the first gain fiber, and the output end of the second cladding light filter is connected to the incident end of the third high reflection fiber grating.

[0010] Preferably, the common cavity laser module further includes a second pumping component, the second pumping component is located between the first gain fiber and the second cladding light filter, or the second pumping component is located between the output end of the low reflection fiber grating and the reflection end of the second high reflection fiber grating.

[0011] Preferably, the second pumping component includes a second beam combiner, a third pump source, and a fourth pump source, the first input end of the second beam combiner is connected to the third pump source, the second input end of the second beam combiner is connected to the reflection end of the second cladding light filter or the second high reflection fiber grating, and the third input end of the second beam combiner is connected to the fourth pump source.

[0012] Preferably, the central wavelength bands of the pump light emitted by the first pump source, the second pump source, the third pump source, and the fourth pump source are all within the absorption peak range of the first gain fiber, and the central wavelength band of the first signal light emitted by the first gain fiber is within the absorption peak range of the second gain fiber.

[0013] Preferably, the reflectivities of the first high reflection fiber grating and the second high reflection fiber grating for the central wavelength band of the first signal light are both greater than 99.5%, the reflectivity of the third high reflection fiber grating for the central wavelength band of the second signal light is greater than 99.5%, and the reflectivity of the low reflection fiber grating for the central wavelength band of the second signal light is 5% - 20%.

[0014] Preferably, the reflection bandwidths of the first high reflection fiber grating, the second high reflection fiber grating, the third fiber grating, and the low reflection fiber grating are greater than or equal to 0.5 nm.

[0015] Preferably, the first gain fiber is a thulium-doped fiber, and the second gain fiber is a holmium-doped fiber.

[0016] The beneficial effects of the present invention are as follows: Different from the prior art, the present invention provides a common-cavity laser module. First, the seed signal light is amplified by the first pump assembly to generate the first signal light, and then the intracavity field strength of the first signal light is enhanced by the fiber resonant external cavity, thereby effectively increasing the pump absorption rate of the gain medium in the fiber resonant internal cavity for the first signal light. Furthermore, the gain medium in the fiber resonant internal cavity can convert more second signal lights, and finally, the common-cavity laser module obtains the target laser with high power and high stability. Since the above-mentioned common-cavity laser module has a "common-cavity structure", it can achieve high-selectivity filtering for specific wavelengths, thereby maximizing the output power of the common-cavity laser module. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of a common-cavity laser module provided by an embodiment of the present invention; Figure 2 It is a schematic structural diagram of a common-cavity laser module provided by another embodiment of the present invention; Figure 3 It is a schematic structural diagram of a co-doped all-fiber laser module provided in Comparative Example 1; In the figure: 100 - fiber resonant external cavity; 10 - first high-reflection fiber grating; 20 - first pump assembly; 21 - first pump source; 22 - second pump source; 23 - first beam combiner; 24 - first gain fiber; 30 - second cladding light filter; 40 - fiber resonant internal cavity; 41 - third high-reflection fiber grating; 42 - second gain fiber; 43 - low-reflection fiber grating; 50 - second high-reflection fiber grating; 60 - first cladding light filter; 70 - second pump assembly; 71 - second beam combiner; 72 - third pump source; 73 - fourth pump source. Detailed Embodiments

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] The purpose of the present invention is to provide a common-cavity laser module for the defects of the prior art, which can output high-power and high-quality continuous laser.

[0020] Please refer to Figure 1 , Figure 1 For Figure 1Schematic diagram of the structure of a common-cavity laser module provided by an embodiment of the present invention; wherein, the present invention provides a common-cavity laser module, including an optical fiber resonant external cavity 100 and a first cladding light filter 60 connected along the transmission direction from the signal input end to the signal output end. The optical fiber resonant external cavity 100 sequentially includes a first high-reflection fiber grating 10, a first pump assembly 20, an optical fiber resonant internal cavity 40, and a second high-reflection fiber grating 50 along the transmission direction; Wherein, the optical fiber resonant external cavity 100 is used to enhance the intracavity field strength of the first signal light emitted by the first pump assembly 20, and enable the first signal light to be absorbed by the gain medium of the optical fiber resonant internal cavity 40 to generate a second signal light; the optical fiber resonant internal cavity 40 is used to output the second signal light after oscillation amplification.

[0021] In the embodiment of the present invention, the first pump assembly 20 is a forward pumping structure. The first pump assembly 20 includes a first pump source 21, a second pump source 22, a first beam combiner 23, and a first gain fiber 24; wherein, the first input end (first pump input arm) of the first beam combiner 23 is connected to the first pump source 21, the second input end of the first beam combiner 23 is connected to the reflection end of the first high-reflection fiber grating 10, and the third input end (second pump input arm) of the first beam combiner 23 is connected to the second pump source 22; the output end of the first beam combiner 23 is fusion spliced to the first end of the first gain fiber 24.

[0022] Specifically, the central wavelengths of the pump light emitted by the first pump source 21 and the second pump source 22 are both within the absorption peak range of the first gain fiber 24. The first pump assembly 20 adopts a forward pumping structure, and the main purpose is to provide pump energy for the first gain fiber 24 in the whole system, so that it can realize functions such as optical signal amplification. The functions of the first pump source 21 and the second pump source 22 are to generate pump light with specific wavelengths and powers. The first pump source 21 and the second pump source 22 work together, and the pump light they output will provide energy for the population inversion in the first gain fiber 24 and create conditions for optical amplification.

[0023] Specifically, the first beam combiner 23 has three input ends. The first input end is connected to the first pump source 21 and is used to input the pump light generated by the first pump source 21; the second input end is connected to the reflection end of the first high-reflection fiber grating 10. The first high-reflection fiber grating 10 is generally used to reflect optical signals with specific wavelengths, and the reflected optical signals here will enter the beam combiner. The third input end is connected to the second pump source 22 and is used to input the pump light generated by the second pump source 22. The function of the beam combiner is to combine these three different optical signals together without mutual interference, so that the combined light can be effectively injected into the first gain fiber 24, thereby enabling the first gain fiber 24 to generate the first signal light.

[0024] In an embodiment of the present invention, the fiber optic resonant cavity 40 sequentially includes a third high - reflection fiber grating 41, a second gain fiber 42, and a low - reflection fiber grating 43 along the transmission direction. The output end of the low - reflection fiber grating 43 is connected to the input end of the first cladding - light filter 60; the central wavelength band of the first signal light emitted by the first gain fiber 24 is within the absorption peak range of the second gain fiber 42.

[0025] Specifically, the third high - reflection fiber grating 41 has the characteristic of high reflection for light of a specific wavelength. Its function is to reflect the optical signals that meet its reflection conditions back into the fiber optic resonant cavity 40, so that these lights form stable resonance in the cavity, thereby enhancing the optical field intensity of the specific wavelength, playing the role of frequency selection and signal enhancement, and ensuring that only the light of a specific wavelength can continuously oscillate and transmit in the cavity.

[0026] Specifically, when the first signal light transmits through the second gain fiber 42 in the fiber optic resonant cavity 40, since the central wavelength band of the first signal light emitted by the first gain fiber 24 is within the absorption peak range of the second gain fiber 42, the active ions in the second gain fiber 42 achieve population inversion distribution and energy - level transition under the action of the first signal light, and then generate the second signal light.

[0027] In an embodiment of the present invention, the common - cavity laser module further includes a second cladding - light filter 30. The input end of the second cladding - light filter 30 is fusion - spliced to the second end of the first gain fiber 24, and the output end of the second cladding - light filter 30 is connected to the input end of the third high - reflection fiber grating 41. Among them, the second cladding - light filter 30 is used to filter out the residual pump light and high - order modes in the first signal light, and the first cladding - light filter 60 is used to filter out the residual pump light and high - order modes in the second signal light.

[0028] In another embodiment of the present invention, the common - cavity laser module further includes a second pump - component 70. The second pump - component 70 includes a second beam combiner 71, a third pump source 72, and a fourth pump source 73. The first input end of the second beam combiner 71 is connected to the third pump source 72, the second input end of the second beam combiner 71 is connected to the reflection end of the second cladding - light filter 30 or the second high - reflection fiber grating 50, and the third input end of the second beam combiner 71 is connected to the fourth pump source 73; Among them, the central wavelength bands of the pump lights emitted by the third pump source 72 and the fourth pump source 73 are both within the absorption peak range of the first gain fiber 24; the second pump - component 70 is located between the first gain fiber 24 and the second cladding - light filter 30, or the second pump - component 70 is located between the output end of the low - reflection fiber grating 43 and the reflection end of the second high - reflection fiber grating 50.

[0029] Specifically, when the second pump assembly 70 is located between the first gain fiber 24 and the second cladding mode stripper 30, or when the second pump assembly 70 is located between the output end of the low reflection fiber grating 43 and the reflection end of the second high reflection fiber grating 50, since the central wavelengths of the pump lights emitted by the third pump source 72 and the fourth pump source 73 are both within the absorption peak range of the first gain fiber 24, and the second gain fiber 42 does not absorb the pump light, the second pump assembly 70 and the first pump assembly 20 form a bidirectional pumping structure, which can pump the first gain fiber 24 more uniformly, making the population inversion distribution in the first gain fiber 24 more uniform and at a higher level, so that a higher output power can be achieved. In contrast, the forward pumping structure injects pump light only from one end. In the case where the first gain fiber 24 is long or the power requirement is high, it may not be able to fully utilize the entire first gain fiber 24 to achieve high-power output.

[0030] In the embodiments of the present invention, the reflectivities of the first high reflection fiber grating 10 and the second high reflection fiber grating 50 for the central wavelength band of the first signal light are both greater than 99.5%, the reflectivity of the third high reflection fiber grating 41 for the central wavelength band of the second signal light is greater than 99.5%, and the reflectivity of the low reflection fiber grating 43 for the central wavelength band of the second signal light is 5% - 20%.

[0031] In the embodiments of the present invention, the reflection bandwidths of the first high reflection fiber grating 10, the second high reflection fiber grating 50, the third fiber grating, and the low reflection fiber grating 43 are greater than or equal to 0.5 nm. A reflection bandwidth greater than or equal to 0.5 nm means that these fiber gratings can effectively reflect light in at least a 0.5 nm wavelength range.

[0032] In the embodiments of the present invention, the combination formed by the first gain fiber 24 and the second gain fiber 42 can be one of a combination formed by a thulium-doped fiber and a holmium-doped fiber, a combination formed by an erbium-ytterbium co-doped fiber and a low-absorption thulium-doped fiber, a combination formed by a ytterbium-doped fiber and an erbium-doped fiber, and a combination formed by a low-absorption thulium-doped fiber and a high-absorption thulium-doped fiber.

[0033] Specifically, the specific working principle of the common cavity laser module provided by the embodiments of the present invention is as follows: The seed signal light enters the first pump assembly 20 through the incident end of the first high-reflection fiber grating 10. The first beam combiner 23 couples the seed signal light and the pump light into the first gain fiber 24. The first gain fiber 24 converts the pump light into the first signal light. After the residual pump light is removed by the second cladding light filter 30, the first signal light enters the fiber resonant inner cavity 40. Since the absorption peak range of the second gain fiber 42 in the fiber resonant inner cavity 40 includes the central band of the first signal light, the active ions in the second gain fiber 42 achieve population inversion distribution and energy level transition under the action of the first signal light, and then generate the second signal light. After the second signal light oscillates and amplifies multiple times in the fiber resonant inner cavity 40 through the third high-reflection fiber grating 41 and the low-reflection fiber grating 43, it is output to the first cladding light filter 60 through the output end of the low-reflection fiber grating 43. The first cladding light filter 60 removes the residual pump light of the second signal light and then outputs it. Since the reflectivities of the first high-reflection fiber grating 10 and the second high-reflection fiber grating 50 for the central band of the first signal light are both greater than 99.5%, the field strength of the first signal light increases due to multiple reflections in the fiber resonant outer cavity 100, thereby effectively increasing the pump absorption rate of the second gain fiber 42 in the fiber resonant inner cavity 40 for the first signal light. Furthermore, the second gain fiber 42 can convert more second signal light, and finally the common-cavity laser module obtains the target laser with high power and high stability.

[0034] Now, the technical solution of the present invention will be described in conjunction with specific embodiments.

[0035] Embodiment 1: Please refer to Figure 1 , the common-cavity laser module provided in this Embodiment 1 includes a fiber resonant outer cavity 100 and a first cladding light filter 60 connected along the transmission direction from the signal input end to the signal output end. The fiber resonant outer cavity 100 sequentially includes a first high-reflection fiber grating 10, a first pump assembly 20, a fiber resonant inner cavity 40, and a second high-reflection fiber grating 50 along the transmission direction; Among them, the fiber resonant outer cavity 100 is used to enhance the intracavity field strength of the first signal light emitted by the first pump assembly 20, and enable the first signal light to be absorbed by the gain medium in the fiber resonant inner cavity 40 to generate the second signal light; the fiber resonant inner cavity 40 is used to output the second signal light after oscillation amplification.

[0036] Specifically, each optical element in the common-cavity laser module in this Embodiment 1 is connected by means of fiber fusion splicing, and the above-mentioned optical elements are configured as follows: The reflectivity of the reflection end of the first high-reflection fiber grating 10 and the reflection end of the second high-reflection fiber grating 50 to 1940 nm is greater than 99.5%, and the bandwidth is 0.5 nm; both the first pump source 21 and the second pump source 22 are 793 nm semiconductor laser modules; the first beam combiner 23 is a high-efficiency fiber beam combiner to ensure low-loss transmission of the signal light when it is transmitted from multiple energy-transmitting fibers to a single fiber in the signal fiber; the first gain fiber 24 is a special thulium-doped fiber, and the 793 nm pump light is within the absorption peak range of the first gain fiber 24; the second gain fiber 42 is a special holmium-doped fiber, and the 1940 nm laser is within the absorption peak range of the second gain fiber 42; the third high-reflection fiber grating 41, the reflectivity of its reflection end to 2100 nm is greater than 99.5%, and the bandwidth is 0.5 nm; the low-reflection fiber grating 43, the reflectivity of its reflection end to 2100 nm is about 10%, and the bandwidth is 0.5 nm; the first cladding light stripper and the second cladding light stripper are used to filter out the residual pump light and high-order modes in the signal light, and their fiber specifications should ensure low-loss transmission of the required components of the passing signal light.

[0037] Specifically, the specific working process of the common-cavity laser module provided in Embodiment 1 is as follows: The 1940 nm seed signal light enters the first pump assembly 20 through the incident end of the first high-reflection fiber grating 10. The first beam combiner 23 couples the 1940 nm seed signal light and the 793 nm pump light into the first gain fiber 24. The first gain fiber 24 converts the pump light into 1940 nm first signal light. After the 1940 nm first signal light removes the residual pump light and high-order modes through the second cladding light filter 30, it enters the fiber resonant inner cavity 40. After the second gain fiber 42 absorbs the 1940 nm first signal light, population inversion distribution and energy level transition are achieved, and then 2100 nm second signal light is generated. After the 2100 nm second signal light is amplified by multiple oscillations in the fiber resonant inner cavity 40, it is output to the first cladding light filter 60 through the output end of the low-reflection fiber grating 43. The first cladding light filter 60 removes the residual pump light of the 2100 nm second signal light and then outputs high-power and high-stable 2100 nm laser.

[0038] Embodiment 2: Please refer to Figure 2, the structure of the common cavity laser module provided in Embodiment 2 is substantially the same as that of the common cavity laser module provided in Embodiment 1, and the difference is only that: the common cavity laser module further includes a second pump assembly 70 located between the output end of the low-reflection fiber grating 43 and the reflection end of the second high-reflection fiber grating 50. The second pump assembly 70 includes a second beam combiner 71, a third pump source 72, and a fourth pump source 73. The first input end of the second beam combiner 71 is connected to the third pump source 72, the second input end of the second beam combiner 71 is connected to the reflection end of the second high-reflection fiber grating 50, and the third input end of the second beam combiner 71 is connected to the fourth pump source 73.

[0039] In Embodiment 2, both the third pump source 72 and the fourth pump source 73 are 793nm semiconductor laser modules; the second beam combiner 71 is a high-efficiency fiber beam combiner.

[0040] Comparative Example 1: Please refer to Figure 3 , Figure 3 is a schematic structural diagram of the co-doped all-fiber laser module provided in Comparative Example 1; among them, the co-doped all-fiber laser module provided in Comparative Example 1 is substantially the same as the common cavity laser module provided in Embodiment 1, and the difference is only that: the co-doped all-fiber laser module provided in Comparative Example 1 does not use the "common cavity structure" and does not include the first high-reflectivity fiber grating, the first gain fiber 24, the second cladding light filter 30, and the second high-reflectivity fiber grating.

[0041] Specifically, in Embodiments 1 to 2, the thulium-ho holmium co-doped fiber is split into a single-doped thulium fiber (the first gain fiber 24) and a single-doped holmium fiber (the second gain fiber 42). By using the characteristic that the quantum loss of the single-doped thulium fiber is lower than that of the thulium-ho holmium co-doped fiber, the heat generation of the fiber is reduced and the fiber efficiency is improved; according to the relationship that the less the heat accumulation at the first gain fiber 24 or the second gain fiber 42, the stronger the stability of the laser module. By optimizing the optical structure design of the laser module, the stability of the laser module is enhanced, the maximum output power of the laser module is increased, and the electro-optical conversion efficiency is improved.

[0042] In addition, in Embodiments 1 to 2, the pump absorption of the second gain fiber 42 is enhanced through a special laser module design (the fiber resonant external cavity 100 structure). This structure can effectively improve the conversion efficiency of the 2100nm laser module, reduce the local accumulation of heat, improve the stability of the laser module, and maximally increase the output power of the laser module. The high-efficiency thulium-ho common cavity all-fiber laser module described in Embodiments 1 to 2 can adapt to various complex usage environments and can achieve high-efficiency laser output in the 2100nm band.

[0043] Specifically, in Embodiments 1 to 2 of the present invention, the means of thulium-holmium co-cavity pumping can better apply various characteristics of 2.1 μm band lasers, reasonably utilize the phenomenon to achieve efficient utilization of the pump beam, reduce local heat accumulation, and thus achieve the purpose of improving the conversion efficiency, increasing the maximum output power threshold, and compacting the laser module structure.

[0044] Comparing Embodiment 2 with Embodiment 1, it can be seen that since the double-directional pumping structure is provided in the fiber resonant external cavity 100 of Embodiment 2, the absorption efficiency of the second gain fiber 42 can be further improved, and the heat accumulation can be reduced. Finally, the 2100 nm laser output power of Embodiment 2 is increased by 15% to 20% compared with that of Embodiment 1.

[0045] When the fiber heat resistance tests are carried out on Embodiment 1 and Comparative Example 1 simultaneously, it can be known that when the pump laser with the same power is injected, the highest melting point temperature of the second gain fiber 42 in Embodiment 1 is 56 °C, while the highest melting point temperature of the second gain fiber 42 in Comparative Example 1 is 86 °C. In addition, the 2100 nm laser output power of Embodiment 1 is significantly higher than that of Comparative Example 1.

[0046] Therefore, in Embodiments 1 to 2 of the present invention, through the co-cavity structure design combined with external cavity enhanced pump absorption and internal cavity high-efficiency oscillation amplification, the output power and stability of the 2.1 μm laser are significantly improved, and at the same time, the energy up-conversion problem of the thulium-holmium co-doped fiber is avoided.

[0047] In summary, different from the prior art, the present invention provides a co-cavity laser module. First, the seed signal light is amplified by the first pump assembly 20 to generate the first signal light, and then the intracavity field strength of the first signal light is enhanced by the fiber resonant external cavity 100, thereby effectively increasing the pump absorption rate of the gain medium in the fiber resonant internal cavity 40 for the first signal light. Furthermore, the gain medium in the fiber resonant internal cavity 40 can convert more second signal lights, and finally, the co-cavity laser module obtains the target laser with high power and high stability. Due to the "co-cavity structure" of the above co-cavity laser module, high-selectivity filtering for a specific wavelength can be achieved, thereby maximally increasing the output power of the co-cavity laser module.

[0048] It should be noted that the above embodiments all belong to the same inventive concept. The descriptions of the embodiments have their own emphases. For the parts not described in detail in individual embodiments, reference can be made to the descriptions in other embodiments.

[0049] The above embodiments merely represent the implementation modes of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A common cavity laser module, characterized in that: It includes a fiber resonant external cavity and a first cladding light filter connected along the transmission direction from the signal input end to the signal output end, and the fiber resonant external cavity includes a first high-reflection fiber Bragg grating, a first pump component, a fiber resonant inner cavity and a second high-reflection fiber Bragg grating in sequence along the transmission direction; The optical fiber resonant external cavity is used to enhance the intracavity field strength of the first signal light emitted by the first pump component, and to make the first signal light be absorbed by the gain medium of the optical fiber resonant inner cavity to generate a second signal light; the optical fiber resonant inner cavity is used to output the second signal light after oscillation and amplification.

2. The common cavity laser module according to claim 1, characterized in that: The first pump component is a forward pump structure, and the first pump component includes a first pump source, a second pump source, a first beam combiner and a first gain fiber; Among them, the first input end of the first beam combiner is connected to the first pump source, the second input end of the first beam combiner is connected to the reflection end of the first high-reflection fiber grating, and the third input end of the first beam combiner is connected to the second pump source; the output end of the first beam combiner is fused with the first end of the first gain fiber.

3. The common cavity laser module according to claim 2, characterized in that: The optical fiber resonant cavity includes a third high-reflection optical fiber Bragg grating, a second gain optical fiber and a low-reflection optical fiber Bragg grating in sequence along the transmission direction, and the output end of the low-reflection optical fiber Bragg grating is connected to the input end of the first cladding light filter.

4. The common cavity laser module according to claim 3, characterized in that: The common cavity laser module further comprises a second cladding light filter, the input end of the second cladding light filter is fused with the second end of the first gain optical fiber, and the output end of the second cladding light filter is connected with the incident end of the third high-reflection optical fiber grating.

5. The common cavity laser module according to claim 4, characterized in that: The common cavity laser module further comprises a second pump component, which is located between the first gain fiber and the second cladding light filter, or between the output end of the low-reflection fiber grating and the reflection end of the second high-reflection fiber grating.

6. The common cavity laser module according to claim 5, characterized in that: The second pump assembly includes a second beam combiner, a third pump source and a fourth pump source, wherein a first input end of the second beam combiner is connected to the third pump source, a second input end of the second beam combiner is connected to the second cladding light filter or the reflection end of the second high-reflection fiber grating, and a third input end of the second beam combiner is connected to the fourth pump source.

7. The common cavity laser module according to claim 6, characterized in that: The central wavelength bands of the pump lights emitted by the first pump source, the second pump source, the third pump source, and the fourth pump source are all within the absorption peak range of the first gain fiber, and the central wavelength band of the first signal light emitted by the first gain fiber is within the absorption peak range of the second gain fiber.

8. The common cavity laser module according to claim 3, characterized in that: The reflectivity of the first high-reflection fiber Bragg grating and the second high-reflection fiber Bragg grating to the central band of the first signal light is greater than 99.5%, the reflectivity of the third high-reflection fiber Bragg grating to the central band of the second signal light is greater than 99.5%, and the reflectivity of the low-reflection fiber Bragg grating to the central band of the second signal light is 5% to 20%.

9. The common cavity laser module according to claim 8, characterized in that: The reflection bandwidths of the first high-reflection fiber grating, the second high-reflection fiber grating, the third fiber grating and the low-reflection fiber grating are greater than or equal to 0.5 nm.

10. The common cavity laser module according to claim 3, characterized in that: The first gain fiber is a thulium-doped fiber, and the second gain fiber is a holmium-doped fiber.

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