Ultra-narrow-linewidth measurement utilizing dual-parameter acquisition through a partially coherent light interference
Zhihui Wang, Changjian Ke, Yibo Zhong, Chen Xing, Haoyu Wang, Keyuan Yang, Sheng Cui, Deming Liu
Abstract
Laser linewidths of the order of 100 Hz are challenging to measure with existing technology. We propose a simple, efficient method to measure ultra-narrow linewidths using dual-parameter acquisition based on partially coherent light interference. The linewidth is obtained using two parameters that are easily extracted from the power spectrum. This method reduces the influence of 1/f noise by utilizing a kilometer-order-length delay fiber and is independent of the fiber-length error for a general situation. Simulation results show that, for a length error less than 10%, the total linewidth measurement error is less than 0.3%. Experimental results confirm the feasibility and superior performance of this method.