Abstract

The multi-dithering method has been well verified in the phase-locking of polarization coherent combination experiments. However, it is difficult to apply to low repetition rate pulsed laser coherent combination, since there exists an overlap in the frequency domain between the pulse laser and the large amplitude-phase noise resulting in traditional filters being unable to effectively separate the phase noise. Aiming to solve the problem, we propose, to the best of our knowledge, a novel method of pulse noise detection, identification, and filtering based on the autocorrelation characteristics between noise signals. The self-designed adaptive window filtering algorithm can effectively filter the pulse signal doped in the phase noise around 0.1 ms. After the pulses are filtered out, the remaining phase noise signal is used as the input signal of the multi-dithering method for phase locking; the phase difference of two pulsed beams (10 kHz) is successfully compensated to zero; and the coherent combination of the closed-loop phase lock is realized. Simultaneously, the phase correction periods are short, the phase lock effect is stable, and the intensity of the final combined pulses rises to the ideal value (${0.9}\;{I_{\rm{max}}}$). In addition, the adaptive window filtering algorithm we proposed can be applied to the coherent combined system of large array fiber lasers and further lay the foundation for fiber phased array lidar.

© 2022 Optica Publishing Group

System design for coherent combined massive fiber laser array based on cascaded internal phase control

Jinhu Long, Rongtao Su, Tianyue Hou, Qi Chang, Min Jiang, Hongxiang Chang, Yu Deng, Yanxing Ma, Pengfei Ma, and Pu Zhou
Appl. Opt. 61(34) 10222-10227 (2022)

Modal decomposition of an incoherent combined laser beam based on the combination of residual networks and a stochastic parallel gradient descent algorithm

Fan Chen
Appl. Opt. 61(14) 4120-4131 (2022)

Phase locking of slab laser amplifiers via square wave dithering algorithm

Zhimeng Huang, Xuan Tang, Dayong Zhang, Xiaojun Wang, Jianfeng Li, Cangli Liu, and Qingsong Gao
Appl. Opt. 53(10) 2163-2169 (2014)

Solid-state biased coherent detection of ultra-broadband terahertz pulses generated in a spintronic emitter for high repetition rate, low pulse energy lasers

Tim Suter, Alessandro Tomasino, Matteo Savoini, Sarah Houver, Roberto Morandotti, Steven L. Johnson, and Elsa Abreu
Opt. Express 30(25) 45202-45211 (2022)

FPGA-based phase control of acousto-optic modulator Fourier synthesis system through gradient descent phase-locking algorithm

Kenneth J. Underwood, Andrew M. Jones, and Juliet T. Gopinath
Appl. Opt. 54(18) 5624-5628 (2015)