非对称相移分布反馈光纤激光器的双向输出波长特性

为了得到单频输出的光纤激光器，常采用带有相移的分布反馈结构，但当耦合强度比较大时，基模的激光功率将集中在相移区，这时，如果相移区太偏离光纤光栅的中心位置，由于空间烧孔效应，相移分布反馈激光器的两端会出现不同的输出波长特性。在接近于相移区的一端，输出为在布拉格波长的基模，而在另一端，输出为位于布拉格波长两侧的一阶模。给出了理论分析和相应的实验结果。

Bidirectional Output Wavelength Characteristics of Asymmetric Phase-Shifted Distributed Feedback Fiber Lasers

The π phase shifted distributed feedback fiber lasers, in which the power would focus on the phase shift region if the coupling strength is high enough, is often used to acquire single frequency output. But due to the spatial hole burning,the output wavelength would be different for the two output ports. The fundamental mode focuses on the port near the phase shift region while the ±1 modes would focus on the other port if the phase shift region is far away from the center of the grating. Both the theoretical analysis and experiments are presented.