多波长掺铒光纤激光器在波分复用光学通信等领域具有广阔的应用前景, 引起了大量关注。为了满足不同场合的应用需求, 本文报道了一种结构紧凑、基于非线性放大光纤环镜的双波长连续运转掺铒光纤激光器。该激光器采用全保偏光纤结构。除了光纤外, 激光腔内只含有波分复用器、2×2光纤耦合器和光纤反射镜3个器件。非线性放大光纤环镜在腔内引入强度相关损耗, 当腔内损耗随着入射光强增加而增加时, 可以有效抑制腔内激光模式竞争。当强度相关损耗的抑制作用和激光模式竞争达到平衡时, 激光器即可实现稳定的多波长输出。在260 mW泵浦功率下, 激光器运转在双波长振荡状态, 输出波长分别为1 5605 nm和1 5632 nm, 边模抑制比达到468 dB。随着泵浦功率的提高, 激光器依次工作在单波长、双波长和三波长运转状态。该激光器结构简单, 操作方便, 具有很好的应用前景。

Multiwavelength erbium-doped fiber lasers can be applied to many fields, such as wavelength division multiplexing optical communication and others attracting considerable attention. To meet the requirements of different applications, we propose a compact dual-wavelength continuous-wave erbium-doped fiber laser based on nonlinear amplifying loop mirror. An all-polarization-maintaining fiber cavity is adopted in which there are only three intracavity devices besides fiber itself: a wavelength division multiplexer, a 2×2 fiber coupler and a fiber reflector. The intensity-dependent loss effect induced by the nonlinear amplifying loop mirror is used to equalize the intensity in the cavity. The input laser with higher power suffers a higher loss than the one with lower power. This feature can be used to suppress mode competition and achieve stable multiwavelength oscillation. With a pump power of 260 mW, dual-wavelength erbium-doped fiber laser can be achieved, with wavelengths of 1 5605 nm and 1 5632 nm, respectively. The side-mode suppression ratio is 468 dB. As pump power increases, the laser can operate in single-, dual- and triple-wavelength regions in proper order. As the multi-wavelength lasing oscillation is a balance between intensity-dependent loss and mode competition, the intensity change breaks the original balance state, resulting in the change in number and wavelength of lasing lines. This laser is simply structured and easy to operate. It can have applications in many fields.