A wavelength tunable linear cavity erbium-doped fiber (EDF) laser based on Sagnac loop incorporating with polarization-maintaining photonic crystal fiber (PM-PCF) was proposed and demonstrated experimentally. The Sagnac loop was composed of 0.5 m length PM-PCF, 1 2 optical coupler with 50:50 splitting ratio, and one polarization controller (PC). For the proposed fiber laser, the working threshold was 35 mW, the 3 m length EDF was used as gain medium, and 0.5 m length EDF was selected as saturable absorber to improve lasers stability. In the experiment, the comb filter effect was generated by Sagnac interferometer, and period was 2.52 nm. When the pump power was 150 mW, single-wavelength tunable laser output was realized within the range of 1528.73–1531.45 nm through adjusting PC, wavelength tuning interval was more than 0.58 nm, power difference was less than 3.681 dB, and signal to noise ratio (SNR) were higher than 31.101 dB. For the designed fiber laser, different groups of dual- and triple-wavelength lasers output were obtained, the power difference was lower than 7.349 and 7.724 dB, and SNR was more than 31.752 and 38.623 respectively. The single-, dual- and triple-wavelength laser stability was test within 20 min, and power and wavelength fluctuation were 3.325 dB and 0.07 nm respectively.

提出了一种基于萨格纳克环并结合保偏光子晶体光纤 (PM-PCF) 的波长可调线性腔掺铒光纤 (EDF) 激光器并进行了实验验证。Sagnac 环路由 0.5 m 长的 PM-PCF、1 个 2 分光比为 50:50 的光耦合器和一个偏振控制器 (PC) 组成。对于所提出的光纤激光器，工作阈值为 35 mW，使用 3 m 长 EDF 作为增益介质，并选择 0.5 m 长 EDF 作为可饱和吸收体以提高激光器稳定性。实验中，梳状滤波器效应由萨格纳克干涉仪产生，周期为2.52 nm。当泵浦功率为150 mW时，通过调整PC实现了1528.73-1531.45 nm范围内的单波长可调激光输出，波长调谐间隔大于0.58 nm，功率差小于3.681 dB，信噪比（SNR）大于31.101 dB。对于所设计的光纤激光器，获得了不同组的双波长和三波长激光器输出，功率差分别小于7.349和7.724 dB，信噪比分别大于31.752和38.623。单波长、双波长和三波长激光器的稳定性在20 min内进行测试，功率和波长波动分别为3.325 dB和0.07 nm。