Method for improving output power, qualities of spectrum and light beam in laser of optical fiber

A fiber laser and output power technology, used in lasers, laser parts, phonon exciters, etc., can solve the problems of wavefront deformation, destruction of ideal mode output, serious thermal distortion effect of high-power fiber lasers, etc., to improve the output. Power, the effect of suppressing the effect of stimulated Raman scattering

Inactive Publication Date: 2005-08-31
TSINGHUA UNIV
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Problems solved by technology

The thermal distortion effect of high-power fiber lasers is severe, causing wavefront deformation and destroying ideal mode output

Method used

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  • Method for improving output power, qualities of spectrum and light beam in laser of optical fiber
  • Method for improving output power, qualities of spectrum and light beam in laser of optical fiber
  • Method for improving output power, qualities of spectrum and light beam in laser of optical fiber

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Experimental program
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Effect test

Embodiment 1

[0038] Such as Figure 9 As shown, the length of the fiber gain medium of the fiber laser is 60m, which is divided into two equal sections, and a section of optical fiber with a high nonlinear coefficient is set between the two sections as a forward phase conjugation device. The nonlinear coefficient of optical fiber is 10W -1 km -1 , the second order dispersion is -1×10 -29 the s 2 / m, the fourth order dispersion is -2×10 -57 the s 4 / m, the fiber length is 1m. The output spectrum processed by the phase conjugate device is as follows Figure 10 shown. Due to the remaining part of the Stokes light in the process of phase conjugation without spectral inversion, this part of the light wave will be parametrically amplified when it is transmitted in a highly nonlinear fiber, which will cause the energy of the laser center frequency to rapidly shift to the Stokes The light transfer of Sri Lanka seriously affects the output power and spectrum quality of the light source. ex...

Embodiment 2

[0040] In order to improve the effect of embodiment 1, on the basis of the structure described in embodiment 1, filters are respectively added at both ends of the high nonlinear fiber to form a forward phase conjugate device, such as Figure 11 shown. The output spectrum processed by the phase conjugate device is as follows Figure 12 shown.

[0041] In Example 2, the low-frequency Stokes light that does not undergo spectrum inversion during the phase conjugation process is filtered out by the filters at both ends of the highly nonlinear fiber, which effectively slows down the transfer of energy at the center frequency to the Stokes light , the output spectrum has been significantly improved. exist Figure 12 Among them, the peak power of the center frequency is 51.3dBm, the peak power of the Stokes spectrum generated by SRS is 31.9dBm, and the difference between the two reaches 19.4dBm. The influence of the SBS effect on the fiber laser can basically be ignored. Compared ...

Embodiment 3

[0044] This embodiment adopts figure 2 In the structure shown, the backward phase conjugate device is realized by using a section of highly nonlinear optical fiber using the principle of stimulated Brillouin scattering. The backward phase conjugate device is used as a cavity mirror of the fiber laser, on the one hand to provide laser feedback, and on the other hand On the one hand, laser spectrum inversion is performed. Since the threshold value of the stimulated Brillouin scattering of the highly nonlinear fiber is very small, the efficiency of the stimulated Brillouin scattering generated by laser incident into the highly nonlinear fiber is very high, and the generated phase conjugate light is opposite to the direction of the incident light. After phase conjugation, the Stokes light of the SRS effect undergoes spectrum inversion, and in the subsequent transmission, the energy is transferred from the Stokes light to the original center frequency as the pump light, thereby su...

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Abstract

The present invention relates to a method for raising output power of fibre-optic laser and quality of its optical spectrum and beam, belonging to the field of laser and optoelectronics. Said invention is characterized by that it utilizes forward phase conjugation and backward phase conjugation to suppress the stimulated Raman scattering effect and compensate the effects of harmful nonlinear optics and thermal aberration, etc. so as to raise the output power of fibre-optic laser and quality of its optical spectrum and beam.

Description

technical field [0001] The invention belongs to the field of laser and optoelectronics. Background technique [0002] Since the first laser came out in 1960, lasers have been widely used in many fields because of their good monochromaticity, directivity and high power. A fiber laser is a laser with an optical fiber as the gain medium. Fiber lasers have lower optical losses and longer gain medium lengths, allowing pump light energy to be absorbed more efficiently. The intracavity laser of high-power fiber lasers is confined in the fiber core, and the core diameter is only a few microns to tens of microns, and the numerical aperture is also low, so the single-mode or low-order intracavity laser can be guaranteed by mode control. Modularity, which structurally ensures that the fiber laser can obtain high beam quality close to the diffraction limit even at very high power output. Fiber lasers use optical fiber as the gain medium. The area-to-volume ratio of the optical fiber ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02F1/35H01S3/00
Inventor 杨昌喜高士明肖晓晟田雨陆思
Owner TSINGHUA UNIV
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