Passive noise suppression in Yb-doped fiber amplifier based on nonlinear amplifying loop mirror

• Published in: Optics and laser technology Vol. 160; p. 109088
• Main Authors: Tang, Zhenqiang, Luo, Daping, Zhou, Lian, Xie, Gehui, Gu, Chenglin, Deng, Zejiang, Xiong, Shiping, Liu, Yang, Li, Wenxue
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2023
• Subjects: Fiber amplifier; Noise suppression; Nonlinear amplifying loop mirror; Nonlinear amplifying loop mirror; Fiber amplifier; Noise suppression
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2022.109088

•A Yb-doped fiber amplifier based on a nonlinear amplifying loop mirror for broadband passive noise suppression and signal amplification.•All polarization-maintaining fiber structure, alignment-free, compact low-noise ultrafast laser amplifier.•The fiber laser system suppressed the amplitude noises from the signal pulses and amplification pump, achieving suppression ratios exceeding 12.7 and 23.0 dB, respectively, with a simultaneous signal amplification ratio reaching 10.0 dB.•The intensity jitter decreased from 0.1 % to 0.03 % (10 Hz–1 MHz) and the phase jitter can be suppressed from 63 to 46 μrad (1 kHz–1 MHz). We investigated the frequency-dependent transfer function of amplitude noise in an all-polarization-maintaining Yb-doped fiber amplifier based on nonlinear amplifying loop mirror (NALM). We generated artificially designed amplitude noise in laser by adding weak sinusoidal modulation into the seed pulses and pump. After transmitting through the NALM-based amplifier, we obtained the amplitude-frequency and phase-frequency responses of the amplitude noise at different gains. Systematic measurements indicate that pump power optimization in the NALM-based amplifier suppresses the amplitude noises from the signal pulses and amplification pump, achieving suppression ratios exceeding 12.7 and 23.0 dB, respectively, with a simultaneous signal amplification ratio reaching 10.0 dB. Moreover, the output noise characteristics confirm that the NALM-based amplifier exhibits broadband amplitude noise and phase noise suppression. Clarifying the mechanism and bandwidth of this amplifier is necessary for low-noise laser generation because it provides insight into the nonlinear laser dynamics of broadband passive noise suppression and signal amplification.