基于空间滤波的光纤激光被动相位锁定技术研究

Passive phase locking of fiber laser based on spatial filtering

基于空间滤波的被动相位锁定,对掺Yb光纤激光阵列的相干组束进行了理论和实验研究.分析了基于空间滤波光反馈相位锁定的原理,研究了远场相干光斑Strehl比与激光波长及光谱带宽的关系.建立了二维四路掺Yb光纤放大器阵列的被动相位锁定实验系统,实现了稳定的相干耦合激光输出,远场光斑Strehl比为0.77.测得输出激光光谱中单个纵模的带宽约为9.1GHz,与理论计算符合较好.

Coherent beam combination of Yb-doped fiber laser array is studied theoretically and experimentally by spatial filtering to passive phase locking.The principle of optical feedback phase locking based on spatial filtering is analyzed,and the relations of Strehl ratio in far field to wavelength and spectrum bandwidth are studied.The coherent beam combination of four Yb-doped fiber amplifier array is achieved experimentally,and stable interference pattern is obtained.The Strehl ratio in far field is 0.77.In the output spectrum,the bandwidth of single longitudinal mode is about 9.1 GHz consistent with the theoretical calculation.