Optical fiber laser mode decomposition method based on phase recovery, and implementation device thereof

Abstract

The invention discloses an optical fiber laser mode decomposition method based on phase recovery, and an implementation device thereof. The method comprises the following four steps: 1, calibrating amode decomposition device through employing a single-mode laser, and adjusting the relative position of an optical element in the mode decomposition device; 2, replacing an optical fiber laser in themode decomposition device, achieving few-mode laser output, and collecting few-mode light spots needed by mode decomposition through the mode decomposition device; 3, recovering the phase of the multimode light spot by using a GS iterative algorithm of the multi-position light spot to obtain the complex amplitude of the multimode light spot; and 4, carrying out mode decomposition on the complex amplitude by adopting a related projection algorithm, and optimizing by taking a mode decomposition result as an initial value of a random parallel gradient descent algorithm. The problem that a traditional random parallel gradient descent algorithm is prone to falling into local optimum due to sensitivity to an initial value is solved, and the number of decomposable modes is increased while the precision is kept.

Description

technical field [0001] The invention relates to the field of laser measurement, in particular to a phase recovery-based optical fiber laser mode decomposition method and an implementation device thereof. Background technique [0002] Laser technology is one of the four major inventions of the twentieth century, along with atomic energy, semiconductors and computers. For more than 40 years, laser technology based on lasers has developed rapidly and has been widely used in various fields such as industrial production, communications, information processing, medical and health, military affairs, cultural education, and scientific research, and has achieved good results. Economic and social benefits play an increasingly important role in national economic and social development. The fiber laser has the advantages of no optical lens in the resonator, no adjustment, no maintenance, and high stability, and is widely used in high-power lasers. However, mode-involved processes such...

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Problems solved by technology

[0004] The object of the present invention is to provide a fiber laser mode decomposition method based on phase recovery and its implementation device, which is not only insensitive to the influence of aberration, but also solves the problem that the traditional numerical analysis method (SPGD) is easy to fall into local problems due to its sensitivity to the initial value. The optimal problem has increased the number of mode decompositions from the original three modes to the current dozen modes

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