Fiber laser beam quality measurement method base on photoelectric detector and CCD camera

Abstract

The invention relates to a fiber laser beam quality measurement method base on a photoelectric detector and a CCD camera. The method comprises: an optical axis of a measured light beam is adjusted to be in a horizontal state, and a beam splitter is arranged at an optical path and thus the measured light beam is divided into two parts that are used for measuring a near field and a far field of the light beam. On the basis of measurement of the near field and the far field of the measured light beam as well as a related data analysis, a near field width and a far field width of the light beam are calculated, so that light beam quality M <2> x and light beam quality M <2>y at a corresponding direction are obtained by calculation. An M<2> factor expression based on near field and far field light intensity distribution of a beam is deduced in theory, so that a defect that the existing M<2> factor measuring instrument can not evaluate the large-size fiber laser beam quality easily can be overcome. The provided fiber laser beam quality measurement method is suitable for fiber laser beam quality measurement including a few of high order modes and some cut fiber laser beam quality measurement.

Description

technical field [0001] The invention relates to a method for measuring optical fiber laser beam quality, in particular to a method for measuring optical fiber laser beam quality based on a photodetector and a CCD camera. Background technique [0002] Beam quality is a very important indicator in the practical application of lasers, and it is generally considered to evaluate the characteristics of laser beams from a qualitative aspect. At present, there are many methods for evaluating the quality of laser beams, such as M 2 factor, beta factor, Strehl ratio, etc. [Feng Guoying, Zhou Shouhuan, "Discussion on Comprehensive Evaluation of Laser Beam Quality", China Laser, 36, 1643-1653 (2009)]. In the 1990s, A.E. Siegman proposed using M 2 factor to evaluate beam quality. M 2 The factor is defined as the ratio of the product of the beam waist width of the actual beam and its far-field divergence angle to the corresponding product of the ideal beam. It is also the most widely ...

AI Technical Summary

Problems solved by technology

The three-point method and the two-point method are more convenient to measure, but the accuracy is not high; the hyperbola fitting method performs hyperbola fitting by measuring multiple points (usually the far field and the near field should measure at least 5 effective points each), so the accuracy Higher, but the implementation is complicated, usually with the help of related precision instruments

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