A Fiber Laser Coherent Combination Method Based on Digital Holography

Abstract

The invention discloses an optical fiber laser coherent combining method based on digital holography. The optical fiber laser coherent combining method based on the digital holography is characterizedin that a detection laser emits a laser beam; the laser beam is divided into two beams by a first polarization beam split prism after going through a first half wave plate and a laser beam expansioncollimating system; the two laser beams perform interference; a local oscillation laser emits laser and the laser is outputted upwardly after being reflected by a second polarization beam split prismafter the laser is amplified in an Er-doped fiber bundle and goes through an optical fiber coupling system and coherent combination is realized. The optical laser coherent combining method based on digital holography only needs a detection CCD camera to realize coherent combining of multiple paths of optical fiber laser. If the number of paths of the laser is increased and then an oversize sectional area is caused, the optical laser coherent combining method based on digital holography can reduce the sectional area to a detectable area of the CCD camera without using an iteration algorithm, avoids facts that the algorithm cannot converge or convergence speed is too slow, has a fast feedback speed, does not need to perform phase control on wavefront of strong laser, avoids thermal distortion and thermal damage of an optical member and is applicable to application in a high power laser system.

Description

technical field [0001] The invention relates to the technical field of laser coherent combination, in particular to a digital holography-based optical fiber laser coherent combination method. Background technique [0002] There are four main ways of beam combining, namely spectral combining, polarization combining, incoherent combining and coherent combining. Spectrum synthesis is to coaxially superimpose and output multi-channel lasers with subtle differences in wavelength to achieve the purpose of increasing laser output power; polarization synthesis is to use a beam splitter coated with a special film system to allow two beams of light with perpendicular polarization to Transmission, one way reflection, through phase locking, the amplitude vectors of transmitted light and reflected light are superimposed stably, so as to achieve the purpose of synthesis; incoherent synthesis is to control the directivity of each beam so that it can be simply superimposed on the target. I...

AI Technical Summary

Problems solved by technology

However, due to many factors such as laser instability, electrical interference, and algorithm errors, the algorithm is not easy to converge in actual use, resulting in the failure of coherent combination

At the same time, due to the influence of thermal damage and nonlinear effects, the theoretical maximum power of a single fiber laser output single-mode laser is limited

If we continue to increase the output power of a single laser on this basis, due to the influence of thermal effects and nonlinear effects of the medium, the beam quality of the output beam will become worse and worse and it is difficult to directly apply it in practice.

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