A pulse-pumped low repetition rate fiber laser coherent combining system

Abstract

Provided is a low-repetition-frequency fiber laser coherent combination system of a pulse pump. According to the system, a continuous laser, an optical fiber coupler and an intensity modulator are used for generating pulse laser seeds, the laser seeds are divided into N branches through a beam splitter, and all branches of laser is amplified through a multi-stage pulse pump optical fiber laser amplifier and then combined into one beam through a beam combiner. Partial combined beams are extracted through a beam splitter mirror and used as feedback signals. In the process of detecting the feedback signals, the intensity modulator is used for eliminating light intensity of a pulse portion, and only continuous signal light among pulses is reserved. Meanwhile, a phase controller operates phase control algorithms only when a detector defects the continuous signal light, and stops the algorithms when the amplifier outputs pulses. Therefore, influences of laser pulse light intensity change on phase control can be removed, phase information contained in continuous lasers is used for real-time correction on phase differences, and finally coherent combination output of the multi-stage pulse pump optical fiber amplifier is achieved.

Description

technical field [0001] The invention relates to coherent combining of fiber lasers, in particular to a coherent combining system of pulse-pumped low repetition frequency fiber lasers. technical background [0002] Fiber lasers have the advantages of high conversion efficiency, good beam quality, convenient thermal management, compact structure, etc., and can obtain laser output with high power and high beam quality. However, due to effects such as optical nonlinear effects and thermal damage, the output power of a single fiber is limited. In order to meet the requirements of high output power of lasers in some application fields, the method of synthesizing and outputting multiple fiber lasers is generally used to obtain high-power fiber laser output. Document 1: S. J. Augst, J. K. Ranka, T. Y. Fan, A. Sanchez. Beam combining of ytterbium fiber amplifiers (Invited) [J]. J. Opt. Soc. Am. B, 2007, 24(8): 1707-1713) . Among them, the coherent combined fiber laser array can ob...

AI Technical Summary

Problems solved by technology

However, the current coherent combination of fiber lasers is aimed at continuous lasers and pulsed lasers with a repetition rate higher than 10 kHz, and there is no effective way to coherently combine such low repetition rate pulsed pump lasers.

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