基于低非线性系数光子晶体光纤的全光纤高效超连续谱光源

All-fiber high-conversion-efficiency supercontinuum source based on photonic crystal fiber with low nonlinear coefficient

报道了一种基于低非线性系数光子晶体光纤的全光纤高效率超连续谱产生系统。将光纤锁模激光器输出的脉宽5 ps、重复频率20 MHz、平均功率50 mW的脉冲,输入到15μm的大模场光纤中进行放大,通过与两级芯径较小的短光纤模场匹配缩小输出的模场直径后,输入到20 m低非线性系数的光子晶体光纤,获得的超连续谱波长覆盖范围宽于650-1 700 nm。输入光子晶体光纤的泵浦光功率为740 mW,输出超连续光功率为670 mW,转换效率大于90%。实验研究了超连续光谱展宽的过程,从理论上进行了分析解释。

An all-fiber high-efficiency supercontinuum source based on photonic crystal fiber with low nonlinear coefficient was demonstrated.The pulse train with 5 ps duration,20 MHz repetition rate,and 50 mW average power output from a mode locked fiber laser was amplified by a 15 μm-diameter large mode fiber amplifier.The output fiber of the amplifier was mode-matched to the photonic crystal fiber using two pieces of short fibers with narrower mode diameter.By pumping the 20 m long low nonlinear coefficient phontonic crystal fiber,a supercontinuum with wavelength extension over 650~1 700 nm was obtained.The output power of the generated supercontinuum was 670 mW pumped by 740 mW input amplified pulses,which implies a conversion efficiency over 90%.The supercontinuum generation process was also experimentally studied and analyzed.