The authors experimentally demonstrate an ultra-low repetition rate passive mode-locked fibre ring laser with a semiconductor optical amplifier works like as a gain medium and non-linear polarisation rotation. A unidirectional erbium-doped fibre amplifier provides additional gain to increase cavity power. By exploiting non-linear polarisation rotation combined with dispersion management stable 5.18 ps optical pulses with 67.2 kHz repetition rate and energy of 1.75 nJ were generated with an extinction ratio >35 dB. The central wavelength is 1557.89 nm and the optical 3-dB bandwidth 1.82 nm very appropriate for optical applications that often require high-peak-power, low repetition rate and picosecond pulses.

中文翻译：

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皮秒脉宽超低重复率无源锁模光纤环形激光器

作者通过实验证明了具有半导体光放大器的超低重复率无源锁模光纤环形激光器的工作原理类似于增益介质和非线性偏振旋转。单向掺铒光纤放大器提供额外增益以增加腔功率。通过利用非线性偏振旋转结合色散管理，产生了具有 67.2 kHz 重复率和 1.75 nJ 能量的稳定 5.18 ps 光脉冲，消光比 > 35 dB。中心波长为 1557.89 nm，光学 3-dB 带宽为 1.82 nm，非常适合通常需要高峰值功率、低重复率和皮秒脉冲的光学应用。