利用自成像腔技术进行光子晶体光纤(PCF)激光器光束相干合成的实验研究,实现了两光子晶体光纤激光器的相位锁定。在不使用滤波器的情况下,实验仍能观测到清晰的干涉图样,且在高功率输出状态以及环境噪声情况下干涉图样仍可保持稳定,表明具有单模大模场特性的光子晶体光纤在实现光束相干合成方面比传统的双包层光纤(DCF)有明显的优越性。实验还表明耦合输出镜的反射率对相干输出功率有一定影响,当反射镜的反射率分别为5%,10%和15%时,两台激光器相干输出斜率效率分别为63.8%,61.6%和60.2%。在抽运功率为150 W和耦合输出镜的反射率为5%时,获得95.8 W的最大相干功率输出,相干功率合成效率为90.2%。实验中无任何热光效应产生,有望利用该方法获得更高的相干输出功率。

Beam coherent combination of two photonic crystal fiber (PCF) lasers is experimentally studied by using self-imaging resonator technique, and phase-locking of the two PCF lasers is achieved. Clear and stable interference strips are observed even without a filter in high-power operation and in environmental noise condition. The advantages of PCF laser in coherent combination over the conventional double-cladding fiber (DCF) are demonstrated. Experiments also show that the reflectivity of coupling output mirror affects coherent output power. The slope efficiencies of two PCF lasers running in in-phase mode are 63.8%, 61.6% and 60.2% for the reflectivity 5%, 10% and 15% of the reflector, respectively. The maximum coherent output power of 95.8W and the combination efficiency of 90.2% are obtained when the pump power is 150 W for the reflectivity of 5%. No thermo-optical problems occur during the experiments, which means that a higher coherent power can be further achieved by using this technique.