A novel widely tunable and interval-adjustable multi-wavelength erbium-doped fiber laser (EDFL) is experimentally demonstrated in this paper. It is based on the cascaded structure of two-segment Sagnac filter and Lyot filter with the assistance of nonlinear polarization rotation (NPR). By properly adjusting the polarization controllers (PCs) in the laser cavity, the output wavelengths with different flexible lasing states can be obtained, such as tunable single-, dual-, triple-wavelength outputs with a tuning range more than 18 nm. The outputs of quad-, quintuple-, sextuple- and septuple-wavelength can also be tuned, but the step size of the tuning is not fixed due to the intense wavelength competition. In addition, the outputs can achieve changes in wavelength interval. The switchability and tuning range of the laser have been greatly improved, and the wavelength interval adjustment is more flexible. The maximum SMSR of the output laser can up to 47 dB. This EDFL can be used in optical fiber sensing, WDM network and other fields desiring very flexible optical source.

本文通过实验证明了一种新型的可广泛调谐和可调间隔的多波长掺fiber光纤激光器（EDFL）。它基于两段Sagnac滤波器和Lyot滤波器的级联结构，并借助非线性极化旋转（NPR）。通过适当调整激光腔中的偏振控制器（PC），可以获得具有不同柔性激光状态的输出波长，例如可调范围大于18 nm的可调谐单波长，双波长，三波长输出。也可以调谐四倍，五倍，六倍和七倍波长的输出，但是由于激烈的波长竞争，调谐的步长不固定。另外，输出可以实现波长间隔的变化。激光器的可切换性和调谐范围得到了极大的改善，波长间隔调整更加灵活。输出激光器的最大SMSR可以高达47 dB。该EDFL可用于光纤传感，WDM网络和其他需要非常灵活的光源的领域。