关键词: 激光技术, 被动锁模光纤激光器, 非线性增益管理放大, 自相似脉冲

Abstract: In mode-locked fiber laser, pump coupling, spectral filtering and polarization dependent isolation loss were simultaneously obtained based on highly integrated fiber component, so as to achieve self-similar passive mode-locked pulses at 1550 nm. At the same time, an all-fiber amplifier was also built for nonlinear gain management amplification, so that the self-similar pulses with 10 dB spectral width of 25.9 nm were successfully amplified and broadened to 52.6 nm, and then compressed to 66 fs by anomalous dispersion fiber. Finally, numerical simulations based on the generalized nonlinear Schrödinger equation and the laser rate equation were carried out to explore the pulses operation process in mode locked fiber laser and fiber amplifier theoretically. The simulation results show that narrow band filter inside the cavity and long normal dispersion gain fiber are necessary conditions for the generation of linearly chirped self-similar mode-locked pulses. And after pre-compression by fiber, self-similar amplification and nonlinear gain-managed amplification of the pulses can be achieved simultaneously with sufficiently long normal dispersion gain fiber, thereby outputting mode-locked pulses with duration less than 100 fs in all-fiber structure.

Key words: laser technique, passively mode-locked fiber laser, nonlinear gain-managed amplification, self-similar pulse