A laser line width measurement method and system

Abstract

The invention discloses a laser line width measurement method and system. The method includes steps: S1, focusing the laser beam to be measured, measuring the spot size value on the focal plane as ω0, and obtaining the initial divergence angle f of the laser beam to be measured as Focal length; S2, performing grating diffraction on the laser beam to be measured to obtain -1-order diffracted light, after focusing the -1-order diffracted light, measure the spot size value on the focal plane as ω', and obtain the grating diffraction to be measured The divergence angle θ' of the laser beam, S3, calculate the line width Δλ=Δθ·d·cosθ of the laser beam to be measured, where d is the grating constant, θ is the diffraction angle of the grating, and the laser to be measured is diffracted by the grating The amount of increase in the divergence angle of the light beam Δθ=θ′−θ0. The present invention also provides a system for realizing the above method. The system includes a diffraction grating, a focusing device, and a light spot measuring device sequentially placed along the exiting optical path of the laser. Compared with the prior art, the system structure of the invention is simple, the method is easy to realize, and is especially suitable for measuring the line width of a narrow line width laser.

Description

technical field [0001] The invention relates to the field of laser technology, in particular to a method and system for measuring the line width of a laser. Background technique [0002] Fiber lasers have the characteristics of high conversion efficiency, compact structure, and excellent beam quality, and have broad application prospects in industry, national defense and other fields. With the development of large mode field double-clad fiber and high-brightness pump source technology, the output power of fiber lasers has increased rapidly. In order to obtain a higher laser output power, a combination technology is proposed, that is, to combine multiple lasers into one output, such as coherent combination and spectral combination, and narrow linewidth lasers are the premise of these high-power laser combination systems. In addition, narrow linewidth lasers have important applications in optical fiber communication networks, optical fiber sensing, and high-precision spectros...

AI Technical Summary

Problems solved by technology

This method has high measurement accuracy, but the biggest limitation is that it cannot measure lasers with wide linewidths, and to obtain second-order Stokes light requires a large injection power, which cannot be tested for low-power lasers.

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