基于光纤环形镜的双级双程L波段高功率ASE光源

研究了L波段光产生的基本机理，基于3dB宽带耦合器的光纤环形镜作为反射镜，优化设计并通过实验得到了双级双程L波段掺Er光纤(EDF)高功率放大的自发辐射(ASE)输出光谱。两级所用的光纤长度分别为7m(低浓度)和31m(高浓度)，在同等条件下，第1级采用双程前向得到功率为21．48mW(13．32dBm)、平均波长为1573．52nm的L波段ASE输出；第1级采用双程后向可实现功率为22．71mW(13．56dBm)、平均波长为1574．66nm的L波段ASE输出。对比分析2种结构输出光谱的抽运光利用效率、光谱平坦度等特性后，得到第1级采用双程后向的双级双程是一种更为理想的实现L波段高功率ASE输出的结构，同时由于C波段易获得高功率(高于30mW)的输出，二者结合即可得到功率高于50mW的C L波段ASE输出。

Two-stage Double-pass L-band Fiber Light Source with High Power Based on Fiber Loop Mirror

The basic principle of L-band is presented,based on 3 dB wide band coupler,the fiber loop mirror with high reflectivity is obtained,through optimal designs and experiments,the two-stage double-pass of L-band with high power amplified spontaneous emission(ASE) fiber source was developed.The fiber lengths of two-stages are about 7 m (low concentration) and 31 m (high concentration respectively,the output power of L-band,when double-pass forward pumping is used in the configuration,is 21.48 mW (13.32 dBm),the mean wavelength is 1 573.52 nm;When double-pass backward pumping is used in the first stage,the output power of L-band is 22.71 mW (13.56 dBm),and the mean wavelength is 1 574.66 nm.By comparison with the characters of the efficiency of pump and the flatness of spectrum,the two-stage double-pass structure with the double-pass backward pumping in the first state is more perfect for the design of L-band with high power.Also,as high power (higher than 30 mW) of C-band is easy to obtain,so output ASE of C+L band (from 1 520 to 1 610 nm) with power higher than 50 mW could be achieved.