利用光纤中的非线性偏振旋转效应提高激光脉冲对比度  

Pulse Contrast Enhancement Based on Nonlinear Polarization Rotation in Optical Fibers

作　　者：汪小超[1] 范薇[1] 张攀政[1] 林尊琪[1] 

机构地区：[1]中国科学院上海光学精密机械研究所,高功率激光物理国家实验室,上海201800

出　　处：《光学学报》2010年第5期1279-1284,共6页Acta Optica Sinica

摘　　要：研究了用于提高激光脉冲对比度的全光纤结构脉冲清洁器(OPC)。对利用非线性偏振旋转效应(NPR)提高脉冲对比度进行了理论分析。计算了脉冲清洁器对主脉冲峰值透射率与入射角度和光纤长度的关系,模拟了输出脉冲波形和脉宽的变化,并对1053 nm波长的百皮秒入射脉冲进行了实验。主脉冲与连续背景噪声的对比度提高47.5 dB以上,主脉冲与预脉冲对比度提高16.94 dB以上,输出信号的连续背景功率和预脉冲强度均低于探测器的最小响应极限。主脉冲的峰值功率透射率达28.05%;脉冲宽度由92 ps压缩至64 ps,与理论预期相符。利用可变衰减加光电转化的方法测量了1 Hz重复频率的脉冲对比度及信号透射率,解决了利用自相关仪不易测量低重复频率信号的问题。采用灵敏度更高的测量方式将测得更高的对比度提升。An all-fiber optical pulse cleaner（OPC） is investigated based on nonlinear polarization rotation（NPR）.The theoretical analysis of pulse contrast enhancement using NPR is detailed.The relation of transmittivity versus incident angle and fiber length is calculated.The change of pulse width and shape of the output pulse is investigated.And an OPC operating at 1053 nm with a hundred picoseconds pulse duration is demonstrated.The pulse contrast between main pulse and continuous wave background power is enhanced by more than 47.5 dB,and the contrast ratio between main pulse and prepulses is enhanced by more than 16.94 dB,which are both beyond the response limit of the detecting devises.The overall peak power transmittivity of the system is 28.05%,and the duration of the pulse is shortened from 92 to 64 ps,which is in agreement with the theoretical prediction.Efficiency measurements are realized using an optical-to-electrical converter and an attenuator,for the autocorrelator is not applicable to the measurement of the pulses with 1 Hz repetition rate.More enhancement of contrast ratio will be detected with precise detection.

关 键 词：光纤光学 脉冲清洁器 非线性偏振旋转 脉冲对比度 全光纤 

分 类 号：TN253[电子电信—物理电子学]