Fiber laser
By using reverse pumping and low absorption coefficient doped truncated fiber technology in 1940nm lasers, the problem of low optical conversion efficiency and output power of existing lasers is solved, achieving higher optical conversion efficiency and output power, while reducing thermal burden and damage risk.
Patent Information
- Application Number
- CN202421851905.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-30
- Publication Date
- 2025-06-10
- Estimated Expiration
- 2034-07-30
AI Technical Summary
The existing 1940nm laser has low light conversion efficiency and low output power.
The 792nm ± 4nm laser output by multiple semiconductor lasers is used as pump light, and the gain is performed through the low absorption coefficient thulle-doped fiber to output a 1940nm laser.
Improves the optical conversion efficiency and output power and peak power, while reducing the risk of damage to the output fiber grating and reducing the thermal burden of the fiber laser.
Smart Images
Figure CN222966498U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of medical devices, and particularly relates to a fiber laser. Background Art
[0002] Because the laser with a wavelength of 1940nm is exactly located on the water absorption peak of the human body, the laser with this wavelength can be used to precisely cut tissues and hardly cause damage to other tissues. In addition, the penetration depth of the laser with a wavelength of 1940nm in tissues is relatively shallow, about 0.1mm - 0.2mm, so the trauma to the human body is small and the harm to the human body is low. Therefore, 1940nm lasers have been developed and applied in the medical field. However, the light conversion efficiency of existing 1940nm lasers is relatively low and the output power is relatively low. Summary of the Utility Model
[0003] The purpose of the utility model is to provide a fiber laser to solve the technical problem of relatively low light conversion efficiency of fiber lasers in the prior art.
[0004] In the fiber laser provided by the utility model, the pump source is connected to the thulium-doped fiber in the resonant cavity in a reverse pumping manner. The pump source includes a plurality of semiconductor lasers and a beam combiner. The wavelength of the laser output by each semiconductor laser is 792nm ± 4nm. The output end of each semiconductor laser is connected to the input end of the beam combiner. The output end of the beam combiner outputs pump light and is connected to the thulium-doped fiber. The fiber laser outputs laser with a wavelength of 1940nm, and the absorption coefficient of the thulium-doped fiber for the pump light is 2.0dB / m - 5.0dB / m.
[0005] The fiber laser provided by the utility model can produce the following beneficial effects:
[0006] The fiber laser provided by the utility model uses the relatively easily obtained laser with a wavelength of 792nm ± 4nm as the pump light to output laser with a wavelength of 1940nm. In order to improve the light conversion efficiency, the utility model uses a thulium-doped fiber with an absorption coefficient of 2.0dB / m - 5.0dB / m for the pump light as the gain medium. Since the absorption coefficient for the pump light is low, a good gain effect can be achieved.
[0007] Compared with forward pumping, the fiber laser provided by the utility model adopts reverse pumping, and the number of reflections of the pump light in the resonant cavity increases. Therefore, the light conversion efficiency, output power and peak power can be further improved. Moreover, by adopting reverse pumping, it can effectively avoid the high-power pump light directly passing through the output fiber grating, thereby reducing the damage risk of the output fiber grating.
[0008] In addition, without considering power loss, the output power and peak power of the fiber laser are respectively the sum of the output powers and the sum of the peak powers of multiple semiconductor lasers. Therefore, by using multiple semiconductor lasers, sufficient output power and peak power can be obtained. When the required output power is fixed, by using multiple semiconductor lasers, the output power of each semiconductor laser can be relatively low, thus effectively controlling heat generation, reducing the thermal burden of the entire fiber laser, and ensuring the normal operation of the fiber laser.
[0009] Further, the thulium doping amount of the thulium-doped fiber is 0.1 at% to 1.1 at%. Through experiments, it is found that the absorption coefficient of the thulium-doped fiber with a thulium doping amount of 0.1 at% to 1.1 at% for laser with a wavelength of 792 nm ± 4 nm is relatively low. Therefore, the fiber laser provided by the present invention uses the thulium-doped fiber with a thulium doping amount of 0.1 at% to 1.1 at% as the gain medium and the laser with a wavelength of 792 nm ± 4 nm as the pump light, which can obtain a relatively high optical conversion efficiency, as well as relatively high output power and peak power.
[0010] Further, the thulium doping amount of the thulium-doped fiber is 0.7 at%; the wavelength of the laser output by each semiconductor laser is 793 nm, and the pump light is the laser with a wavelength of 793 nm. Through experiments, it is found that the absorption coefficient of the thulium-doped fiber with a thulium doping amount of about 0.7 at% for the laser with a wavelength of 793 nm is relatively low, and the laser with a wavelength of 793 nm is relatively easy to obtain. Therefore, in order to obtain higher optical conversion efficiency, output power and peak power as much as possible, and at the same time to make the fiber laser provided by the present invention more simple, the present invention uses the thulium-doped fiber with a thulium doping amount of 0.7 at% as the gain medium and the laser with a wavelength of 793 nm as the pump light.
[0011] Further, the length range of the thulium-doped fiber is 3 m to 7 m. Within this length range, good gain can be obtained while controlling the cost from being too high.
[0012] Further, the beam combiner is a (6 + 1)*1 beam combiner, and the lasers output by the six semiconductor lasers form the pump light through the (6 + 1)*1 beam combiner.
[0013] Under this technical solution, the pump source uses six semiconductor lasers, and the number of semiconductor lasers is relatively large, and the (6 + 1)*1 beam combiner is relatively easy to obtain. Therefore, such a setting can make the fiber laser provided by the present invention more simple while obtaining high output power, high peak power and low thermal burden, and can reduce the manufacturing difficulty of the fiber laser.
[0014] Further, the output power range of the semiconductor laser is 5W to 50W.
[0015] Further, a high-reflection fiber grating is provided at the input end of the thulium-doped fiber, and a low-reflection fiber grating is provided at the output end of the thulium-doped fiber. The reflectivity of the high-reflection fiber grating to the laser with a wavelength of 1940 nm is greater than 98%, and the transmittance to the pump light is greater than 99%; the reflectivity of the low-reflection fiber grating to the laser with a wavelength of 1940 nm is 5% to 20%; the resonant cavity is formed between the high-reflection fiber grating and the low-reflection fiber grating.
[0016] Under this technical solution, the high-reflection fiber grating as the input fiber grating can effectively reflect the laser of the target wavelength and transmit the pump light, thereby improving the purity of the output laser; while the low-reflection fiber grating as the output fiber grating can allow most of the laser of the target wavelength to output, ensuring power output, and at the same time can retain a part of the laser of the target wavelength to continue to oscillate in the resonant cavity. For example, a fiber grating with a reflectivity of 10% to the laser of the target wavelength can be selected as the output fiber grating, which can make 90% of the laser of the target wavelength output, while retaining 10% of the laser of the target wavelength to continue to oscillate in the resonant cavity.
[0017] Further, a light detection element is provided at the input end of the resonant cavity of the fiber laser for detecting the intensity of the laser with a wavelength of 1940 nm in the optical path.
[0018] Under this technical solution, the light detection element can be a photodiode. By detecting the intensity of the laser of the target wavelength in the optical path, information such as whether the output power is sufficient and whether the fiber laser is normal can be obtained. For example, if the light detection element cannot detect the laser of the target wavelength, it means that the fiber laser may malfunction; if the light detection element detects that the intensity of the laser of the target wavelength is insufficient, it means that the output laser of the fiber laser is not enough to meet the usage requirements.
[0019] Further, the wavelength of the aiming light of the fiber laser is 520 nm, and its light source and the light detection element are both connected to the input end of the resonant cavity of the fiber laser through a multiplexer. Description of the Drawings
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.
[0021] Figure 1Schematic diagram of the principle of the fiber laser provided by the embodiment of the present invention.
[0022] Explanation of reference numerals:
[0023] 100 - Thulium-doped fiber; 200 - Semiconductor laser; 300 - (6 + 1)*1 beam combiner; 400 - High-reflection fiber grating; 500 - Low-reflection fiber grating; 600 - Optical detection element; 700 - Light source for aiming light; 800 - Multiplexer; 900 - Fiber jumper. Detailed implementation manners
[0024] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0025] This embodiment provides a fiber laser, as Figure 1 shown. Its pump source is connected to the thulium-doped fiber 100 in a reverse pumping manner in the resonant cavity. The pump source includes a plurality of semiconductor lasers 200 and a beam combiner. The wavelength of the laser output by each semiconductor laser 200 is 792 nm ± 4 nm. The output end of each semiconductor laser 200 is connected to the input end of the beam combiner. The output end of the beam combiner outputs pump light and is connected to the thulium-doped fiber 100. The fiber laser outputs laser with a wavelength of 1940 nm. The absorption coefficient of the thulium-doped fiber 100 for the pump light is 2.0 dB / m to 5.0 dB / m.
[0026] The fiber laser provided by this embodiment uses the relatively easily obtained laser with a wavelength of 792 nm ± 4 nm as the pump light to output laser with a wavelength of 1940 nm. In order to improve the optical conversion efficiency, this embodiment uses the thulium-doped fiber 100 with an absorption coefficient of 2.0 dB / m to 5.0 dB / m for the pump light as the gain medium. Since the absorption coefficient for the pump light is low, it can achieve a good gain effect.
[0027] Compared with forward pumping, the fiber laser provided by this embodiment uses reverse pumping. The number of reflections of the pump light in the resonant cavity increases. Therefore, it can further improve the optical conversion efficiency, output power, and peak power. Moreover, by using reverse pumping, it can also effectively avoid the high-power pump light directly passing through the output fiber grating, thereby reducing the risk of damage to the output fiber grating.
[0028] In addition, since, without considering power loss, the output power and peak power of the fiber laser are respectively the sum of the output powers and the sum of the peak powers of multiple semiconductor lasers 200, multiple semiconductor lasers 200 can be used to obtain sufficient output power and peak power. When the required output power is fixed, by using multiple semiconductor lasers 200, the output power of each semiconductor laser 200 can be relatively low, thereby effectively controlling heat generation, reducing the thermal burden of the entire fiber laser, and ensuring the normal operation of the fiber laser.
[0029] Specifically, in this embodiment, the thulium doping amount of the thulium-doped fiber 100 is 0.1 at% to 1.1 at%, that is, the doping amount of thulium ions (Tm 3+ ) in the gain medium is 0.1 at% to 1.1 at%. Through experiments, it is found that the absorption coefficient of the thulium-doped fiber with a thulium doping amount of 0.1 at% to 1.1 at% for laser with a wavelength of 792 nm ± 4 nm is relatively low. Therefore, the fiber laser provided in this embodiment uses a thulium-doped fiber with a thulium doping amount of 0.1 at% to 1.1 at% as the gain medium and laser with a wavelength of 792 nm ± 4 nm as the pump light, which can obtain a relatively high optical conversion efficiency, as well as relatively high output power and peak power. The absorption coefficient of the thulium-doped fiber 100 for laser with a wavelength of 792 nm ± 4 nm is proportional to the thulium doping amount. In actual situations, the thulium doping amount of the thulium-doped fiber 100 can be adjusted according to needs.
[0030] More specifically, in this embodiment, the thulium doping amount of the thulium-doped fiber 100 is 0.7 at%, the wavelength of the laser output by each semiconductor laser 200 is 793 nm, the pump light is laser with a wavelength of 793 nm, and the absorption coefficient of the thulium-doped fiber 100 for laser with a wavelength of 793 nm is 3.5 dB / m. Through experiments, it is found that the absorption coefficient of the thulium-doped fiber 100 with a thulium doping amount of about 0.7 at% for laser with a wavelength of 793 nm is relatively low, and laser with a wavelength of 793 nm is relatively easy to obtain. Therefore, in order to obtain as high optical conversion efficiency, output power, and peak power as possible, and at the same time to make the fiber laser provided in this embodiment simpler, this embodiment uses a thulium-doped fiber 100 with a thulium doping amount of 0.7 at% as the gain medium and laser with a wavelength of 793 nm as the pump light.
[0031] More specifically, in this embodiment, the length range of the thulium-doped fiber 100 is 3 m to 7 m. Within this length range, good gain can be obtained while controlling the cost from being too high.
[0032] Specifically, in this embodiment, as Figure 1As shown, the beam combiner is a (6 + 1)*1 beam combiner 300. The lasers output by six semiconductor lasers 200 form pump light through the (6 + 1)*1 beam combiner 300. The pump source uses six semiconductor lasers 200. The number of semiconductor lasers 200 is relatively large, and the (6 + 1)*1 beam combiner 300 is relatively easy to obtain. Therefore, such a setting can make the fiber laser provided in this embodiment simpler while obtaining high output power, high peak power, and low heat load, and can reduce the manufacturing difficulty of the fiber laser.
[0033] Specifically, in this embodiment, the output power range of the semiconductor laser 200 is 5W to 50W. More specifically, when the total power of multiple semiconductor lasers 200 is 100W, 180W, 500W respectively, and the thulium doping amount of the thulium-doped gain fiber is 0.7 at%, the lengths of the optimal thulium-doped gain fibers are 3.1m, 4.2m, 5.5m respectively. In this way, the obtained laser conversion efficiency is relatively high, and the generated additional heat load is relatively small.
[0034] Specifically, in this embodiment, a high-reflection fiber grating 400 is provided at the input end of the thulium-doped fiber 100, and a low-reflection fiber grating 500 is provided at the output end of the thulium-doped fiber 100. The reflectivity of the high-reflection fiber grating 400 to the laser with a wavelength of 1940nm is greater than 98%, and the transmittance to the pump light is greater than 99%; the reflectivity of the low-reflection fiber grating 500 to the laser with a wavelength of 1940nm is 5% to 20%; a resonant cavity is formed between the high-reflection fiber grating 400 and the low-reflection fiber grating 500. With such a setting, the high-reflection fiber grating 400 as the input fiber grating can effectively reflect the laser of the target wavelength and transmit the pump light, thereby improving the purity of the output laser and reducing the damage risk of the output fiber grating; while the low-reflection fiber grating 500 as the output fiber grating can allow most of the laser of the target wavelength to output, ensure power output, and at the same time can retain a part of the laser of the target wavelength to continue to oscillate in the resonant cavity. For example, a fiber grating with a reflectivity of 10% to the laser of the target wavelength can be selected as the output fiber grating, so that 90% of the laser of the target wavelength can be output, and 10% of the laser of the target wavelength can be retained to continue to oscillate in the resonant cavity. The output end of the low-reflection fiber grating 500 is connected to the fiber patch cord 900.
[0035] Specifically, in this embodiment, a light detection element 600 is provided at the input end of the resonant cavity of the fiber laser for detecting the intensity of the laser with a wavelength of 1940 nm in the optical path. More specifically, the light detection element 600 can be a photodiode. By detecting the intensity of the laser with the target wavelength in the optical path, information such as whether the output power is sufficient and whether the fiber laser is normal can be obtained. For example, if the light detection element 600 fails to detect the laser with the target wavelength, it indicates that the fiber laser may malfunction; if the light detection element 600 detects that the intensity of the laser with the target wavelength is insufficient, it means that the output laser of the fiber laser is not sufficient to meet the usage requirements.
[0036] Specifically, in this embodiment, the wavelength of the aiming light of the fiber laser is 520 nm, and the light source 700 of the aiming light and the light detection element 600 are both connected to the input side of the resonant cavity of the fiber laser through a multiplexer 800. Of course, in other embodiments of the present application, light with a wavelength near 520 nm can also be used as the aiming light as long as its output effect can be ensured.
[0037] In summary, this embodiment provides a fiber laser. The gain medium is a thulium-doped fiber 100, and the pump light is pumped in the resonant cavity in the reverse direction, capable of outputting laser with a wavelength of 1940 nm. It not only has a high optical conversion efficiency, but also has relatively high output power and peak power, and the output laser has high safety for the human body. In addition, the fiber laser provided in this embodiment has a simple structure and a relatively small volume, which is convenient to use.
[0038] Finally, it should also be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to this process, method, article or device.
[0039] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to the embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A fiber laser, characterized in that: The pump source of the fiber laser is connected to the thulium-doped fiber (100) in a resonant cavity by reverse pumping. The pump source comprises a plurality of semiconductor lasers (200) and a beam combiner. The wavelength of the laser light output by each semiconductor laser (200) is 792nm±4nm. The output end of each semiconductor laser (200) is connected to the input end of the beam combiner. The output end of the beam combiner outputs pump light and is connected to the thulium-doped fiber (100). The fiber laser outputs 1940nm laser light. The absorption coefficient of the thulium-doped fiber (100) to the pump light is 2.0dB / m to 5.0dB / m.
2. The fiber laser according to claim 1, characterized in that: The thulium doping amount of the thulium-doped optical fiber (100) is 0.1 at-1.1 at%.
3. The fiber laser according to claim 2, characterized in that: The thulium doping amount of the thulium-doped optical fiber (100) is 0.7 at %; the wavelength of the laser light output by each of the semiconductor lasers (200) is 793 nm, and the pump light is a laser light with a wavelength of 793 nm.
4. The fiber laser according to any one of claims 1 to 3, characterized in that: The length of the thulium-doped optical fiber (100) ranges from 3m to 7m.
5. The optical fiber laser according to claim 4, characterized in that: The beam combiner is a (6+1)*1 beam combiner (300), and the lasers output by the six semiconductor lasers (200) form the pump light through the (6+1)*1 beam combiner (300).
6. The optical fiber laser according to claim 5, characterized in that: The output power range of the semiconductor laser (200) is 5W to 50W.
7. The optical fiber laser according to claim 1, characterized in that: The input end of the thulium-doped optical fiber (100) is provided with a high-reflection optical fiber grating (400), and the output end of the thulium-doped optical fiber (100) is provided with a low-reflection optical fiber grating (500); the reflectivity of the high-reflection optical fiber grating (400) to laser light with a wavelength of 1940 nm is greater than 98%, and the transmittance to the pump light is greater than 99%; the reflectivity of the low-reflection optical fiber grating (500) to laser light with a wavelength of 1940 nm is 5% to 20%; the resonant cavity is formed between the high-reflection optical fiber grating (400) and the low-reflection optical fiber grating (500).
8. The fiber laser according to claim 1, characterized in that: The input end of the resonant cavity of the optical fiber laser is provided with a light detection element (600) for detecting the intensity of the laser with a wavelength of 1940 nm in the optical path.
9. The optical fiber laser according to claim 8, characterized in that: The wavelength of the aiming light of the fiber laser is 520 nm, and the light source (700) of the aiming light and the light detection element (600) are both connected to the input end of the resonant cavity of the fiber laser via a multiplexer (800).