基于预畸变和光锁相的线性扫频激光源生成

Linearized Frequency-Swept Laser Source Generation Based on Pre-Distortion and Optical Phase-Locked Loop

线性扫频激光源在高分辨率、高精度、大动态范围的激光测量和光纤传感领域有着广泛的应用。然而,扫频非线性及激光相位噪声限制了测量系统的分辨率、精度和动态范围。分析了分布反馈式(DFB)半导体激光扫频中的非线性及激光相位噪声产生的机制,提出基于预畸变和光锁相的激光扫频非线性校正和激光相位噪声抑制方法,实现了扫频范围为50 GHz,均方根频率误差小于263 k Hz的激光扫频信号。实验测试表明该扫频激光源的线性度和相干性得到了有效增强。

Linearly frequency-swept laser source is widely used in high spatial resolution, precision and dynamic range light measuring and optic fiber sensor. However, the frequency-swept nonlinearity and the phase noise of the laser source limit the system spatial resolution, precision and dynamic range. The mechanism of the nonlinearity and phase noise in frequency-swept distributed feedback （DFB） semiconductor laser is analyzed, the combination of pre-distortion and optical phase-locked loop is proposed to overcome the nonlinearity of the frequency sweep, and the phase noise of the laser source is suppressed. Chirp of 50 GHz is achieved where the root mean square frequency error is less than 263 kHz. And the performance of the frequency-swept laser source linearity and coherence enhancement is demonstrated.