室温稳定的多波长光纤激光器(MWFL)中最关键的技术是如何有效抑制掺杂光纤的均匀展宽效应。综述了国际上近年来提出的实现室温稳定多波长光纤激射的主要技术。介绍了近几年我们在该领域的一些创新性研究工作：提出了多种基于多谐振峰的光纤布拉格光栅(FBG),如多模光纤布拉格光栅、保偏光纤布拉格光栅、取样光纤布拉格光栅等的可开关多波长光纤激光器的新方法和新结构,实现了多种波长间隔小于2 nm,室温工作稳定性好、波长及波长间隔可调的可开关多波长光纤激光器; 提出了基于非线性光纤环镜(NOLM)和非线性偏振旋转(NPR)效应的两种多波长掺铒光纤激光器(EDFL)实现技术,实现了室温稳定、功率谱分布平坦的宽带多波长激光输出,3 dB带宽内的波长个数可达50个,每个波长的功率波动在2 h内小于0.1 dB。

The key technologies of achieving room-temperature stable multi-wavelength fiber lasers (MWFLs) are how to restrain the homogeneous broadening effect of the doped fiber at room temperature. We summarize the main technologies and methods reported recently to realize the room-temperature MWFLs, and introduce our innovative works in this field, including proposing several novel structures and operable technologies of switchable multi-wavelength fiber lasers using special fiber Bragg gratings (FBG) with several resonance peaks, such as FBG in multimode fiber, FBG in polarization maintaining fiber and sampled FBG. Switchable multi-wavelength fiber lasing oscillations with less than 2 nm wavelength spacing, tunable wavelength and spacing and excellent room-temperature stability were demonstrated and realized. Two other erbium-doped MWFL designs are proposed respectively by using nonlinear polarization rotation (NPR) effect and a nonlinear optical loop mirror (NOLM) to induce intensity-dependent loss. As a result, power-stable, broad bandwidth and uniform multiwavelength operations are obtained for both laser sources. Up to 50 wavelengths lasing oscillations with wavelength spacing of 0.8 nm within a 3 dB spectral range of 1562～1605 nm have been achieved. The measured power fluctuation of each wavelength is about 0.1 dB within a two-hour period.