Composite chamber adjustable Raman optical fiber laser

Abstract

This invention relates to a fiber laser, the technology of which includes: taking the output light of a large power laser with the central wavelength of 1070nm as the pump light to enter into the cascade structure linear resonate cavity composed of Raman gain fiber and fiber gratings, the energy of which is converted to the long wavelength light steadily via Stokes at different levels to get the necessary output band. In the process of the transformation from the last-but-one level Stokes light to the last, a narrowband tuned filter ring resonate cavity is used to obtain large sphere of laser output at the needed bands under the combined action of wide band gain property of the Si elements in Raman fiber and the narrow band tuning.

Description

technical field [0001] The invention relates to a fiber laser, in particular to a tunable Raman fiber laser with a composite cavity. Background technique [0002] At present, there are generally the following methods for making tunable lasers at home and abroad: (1) tunable distributed feedback lasers; (2) tunable distributed Bragg reflector lasers; (3) tunable micro-motor system vertical cavity surface emitting lasers; (4) Tunable external cavity laser; (5) Tunable laser based on erbium-doped fiber. Among them, methods (1) and (2) both use the method of changing the injection current to adjust the refractive index of some materials in the laser, so as to realize the tuning of the laser wavelength, but the tuning range of the laser is greatly limited by this method , the maximum is only about 16nm; method (3) using the method of moving the mirror position to change the laser wavelength can greatly improve the tuning range, but usually it is necessary to construct two Braggs...

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Problems solved by technology

Among them, methods (1) and (2) both use the method of changing the injection current to adjust the refractive index of some materials in the laser, so as to realize the tuning of the laser wavelength, but the tuning range of the laser is greatly limited by this method , the maximum is only about 16nm; method (3) using the method of moving the mirror position to change the laser wavelength can greatly improve the tuning range, but usually it is necessary to construct two Braggs on both sides of the quantum well light emitting region with a thickness of only tens of nanometers Mirror, the process is complicated and the cost is high; method (4) uses the grating to form an external cavity to adjust the laser wavelength, which can also improve the tuning range, but requires bulky mechanical and optical components, which limits its application range. Although the external cavity tunable laser produced by the micro-mechanical system reduces the volume, it also has the problems of complex process and high cost; method (5) utilizes the broadband gain of the erbium fiber, and adds a filter element in the loop to control the excitation of the laser. The method is simple and stable, but the tuning range is limited by the gain bandwidth of erbium ions (generally about 30nm), which is still difficult to meet the needs

Therefore, there are defects in these several methods, and it is difficult to fully meet the actual needs.

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