基于3×3耦合器的窄线宽单频激光器噪声测量技术

Narrow Linewidth Single-Frequency Laser Noise Measurement Based on a 3×3 Fiber Coupler

提出一种基于3×3耦合器的非平衡迈克耳孙干涉仪的延时自外差技术,理论分析了此技术用于测量窄线宽单频激光器噪声的原理,搭建了测试系统,对Emcore公司的分布反馈式(DFB)半导体激光器以及NKT公司的商用超窄线宽DFB光纤激光器这两类典型光源的相位噪声、频率噪声以及线宽进行了测试。结果表明,此技术可以用于完整地测试不同类型激光器的噪声特性,并且验证了此技术的正确性和稳健性。

A new delayed self-heterodyne technique using an unbalanced Michelson interferometer （MI） composed of a 3×3 optical fiber coupler is proposed. The principle of the technique to measure the laser phase and frequency noise are analyzed theoretically. The experimental setup is introduced. Also, the technique is used to characterize the phase noise power spectral density （PSD）, frequency noise PSD and linewidth of two typical kinds of lasers, distributed feedback （DFB） semiconductor laser （Emcore） and super-narrow linewidth DFB fiber laser （NKT）. The results show that the technique can measure the noise characters of different kinds of lasers and it confirms the correction and robustness of the proposed technique.