Fiber laser for improving Raman optical threshold
Technical Field
The invention relates to the technical field of lasers, in particular to a fiber laser for improving a Raman light threshold.
Background
In the technical field of high-power continuous fiber lasers, the raman effect is a bottleneck limiting a single-cavity laser to realize higher power output. Since the raman effect, after it has increased to a certain extent, will cause irreversible damage to the laser. Raising the raman threshold of the fiber itself requires research in the materials from which the fiber is made. At present, under the condition that the materials for manufacturing optical fibers do not break through, how to utilize other technologies to improve the threshold value of raman light and obtain higher output power of a single-cavity laser is a technical problem to be solved urgently by many laser manufacturers at home and abroad.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: how to obtain higher output power of the single-cavity laser.
In order to solve the technical problems, the invention adopts the technical scheme that:
the invention provides an optical fiber laser for improving a Raman optical threshold, which comprises at least 2 first pump sources, a first pump light beam combiner, a resonant cavity, a gain optical fiber, a passive optical fiber and an output head;
the first pumping source comprises at least two wavelengths, the pumping source is connected with the first pumping light beam combiner, the gain optical fiber is arranged in the resonant cavity, and the passive optical fiber is sequentially connected with the first pumping light beam combiner, the resonant cavity and the output head.
The passive optical fiber laser further comprises a second pump light beam combiner, the second pump light beam combiner is connected with at least two second pump sources, the second pump sources comprise at least two wavelengths, and the passive optical fiber is connected with the second pump light beam combiner.
Further, the pump power of one side of the second pump light beam combiner is greater than the pump power of one side of the first pump light beam combiner.
Furthermore, the core diameters of the passive optical fiber, the gain optical fiber and the passive optical fiber connected with the output head in the resonant cavity are larger than or equal to 20 microns.
Further, the length of the passive optical fiber in the resonant cavity is not more than 3 m.
Further, the length of the gain fiber is not less than ten meters.
Further, the length of the gain fiber is 25 meters.
The invention has the beneficial effects that: the pump with two or more wavelengths is used as the pump source of the laser, and the length of the gain fiber can be shortened by using the pump source with high absorption rate wavelength in the absorption spectrum of the gain fiber on the premise of ensuring the absorption value of the gain fiber of the laser, so that the threshold value of Raman light is improved.
Drawings
The detailed structure of the invention is described in detail below with reference to the accompanying drawings
Fig. 1 is a schematic structural diagram of a fiber laser for increasing a raman optical threshold according to the present invention.
In fig. 1:
101-A wavelength pump source, 102-B wavelength pump source, 103-first pump light beam combiner, 104-resonant cavity, 105-gain fiber, 106-second pump light beam combiner, 107-passive fiber connected with output head, 108-output head, 109-passive fiber in resonant cavity, 110-passive fiber, 111-A wavelength pump source, 112-B wavelength pump source
Detailed Description
In order to explain technical contents, structural features, and objects and effects of the present invention in detail, the following detailed description is given with reference to the accompanying drawings in conjunction with the embodiments.
Referring to fig. 1, the present invention provides a fiber laser for increasing a raman optical threshold, which includes at least 2 first pump sources (an a-wavelength pump source 101 and a B-wavelength pump source 102), a first pump beam combiner 103, a resonant cavity 104, a gain fiber 105, a passive fiber 110, and an output head 108. The first pump source comprises at least two wavelengths, the first pump source is connected to the first pump beam combiner 103, a gain fiber 105 is disposed in the resonant cavity 104, and the passive fiber 110 is sequentially connected to the first pump beam combiner 103, the resonant cavity 104, and the output head 108.
The output wavelength of the B-wavelength pump source 102 has a higher absorption in the absorption spectrum of the gain fiber 105 than the output wavelength of the a-wavelength pump source 101.
From the above description, the beneficial effects of the present invention are: the pump with two or more wavelengths is used as the pump source of the laser, and the length of the gain fiber can be shortened by using the pump source with high absorption rate wavelength in the absorption spectrum of the gain fiber on the premise of ensuring the absorption value of the gain fiber of the laser, so that the threshold value of Raman light is improved.
Example 1
In a specific embodiment, the present invention provides a fiber laser for increasing a raman light threshold, the fiber laser further includes a second pump light beam combiner 106, the second pump light beam combiner 106 is connected to at least two second pump sources (an a-wavelength pump source 111 and a B-wavelength pump source 112), the second pump sources include at least two wavelengths, the passive fiber 110 is connected to the second pump light beam combiner 106, and a pump power of a side of the second pump light beam combiner 106 is greater than a pump power of a side of the first pump light beam combiner 103. Under the condition of adopting double-end pumping, the pumping power of one side of the second pumping light beam combiner 106 is larger than that of one side of the first pumping light beam combiner 103, so that the power distribution in the laser can be dispersed, the power density of the optical fiber core of the laser is reduced, and the threshold value of Raman light is improved.
Example 2
In a specific embodiment, the invention provides a fiber laser for increasing the raman light threshold, in which the core diameters of the passive fiber 109, the gain fiber 105 and the passive fiber 107 connected to the output head 108 in the resonant cavity 104 are greater than or equal to 20 μm. The core diameter of the optical fiber core is increased, and under the same laser power, the power density of the optical fiber core of the laser is obviously reduced, so that the threshold value of Raman light is improved.
Example 3
In a specific embodiment, the invention provides a fiber laser for increasing the raman light threshold, in which the passive fiber 109 in the resonant cavity 104 does not exceed 3 m. The passive fiber 109 in the cavity 104 does not exceed 3m, which reduces the internal power density of the laser and thus increases the threshold of the raman light.
Example 4
In a specific embodiment, the present invention provides a fiber laser for increasing a raman optical threshold, where a length of a gain fiber 105 in the fiber laser for increasing the raman optical threshold is not less than ten meters, and further, a length of the gain fiber 105 is 25 meters. Setting the gain fiber 105 to 25 meters reduces the power density of the laser fiber core, thereby increasing the threshold of the raman light.
In summary, in the fiber laser for increasing the raman light threshold provided by the present invention, two or more wavelength pumps are used as the pump sources of the laser, and the length of the gain fiber can be shortened by using the pump source having a high absorption wavelength in the absorption spectrum of the gain fiber on the premise of ensuring the absorption value of the gain fiber of the laser, so that the raman light threshold is increased. Under the condition of adopting double-end pumping, the pumping power of one side of the second pumping light beam combiner is larger than that of one side of the first pumping light beam combiner, so that the power distribution in the laser can be dispersed, the power density of the optical fiber core of the laser is reduced, and the threshold value of Raman light is improved. The increase of the core diameter of the optical fiber core can obviously reduce the power density of the optical fiber core of the laser under the same laser power, and further improve the threshold value of Raman light. The passive optical fiber in the resonant cavity does not exceed 3m, so that the internal power density of the laser can be reduced, and the threshold value of Raman light is further improved. The gain fiber is set to be 25 meters, so that the power density of the fiber core of the laser fiber is reduced, and the threshold value of Raman light is further improved.
The first … … and the second … … are only used for name differentiation and do not represent how different the importance and position of the two are.
Here, the upper, lower, left, right, front, and rear merely represent relative positions thereof and do not represent absolute positions thereof
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.