Frequency Noise Characterization of Laser Sources Based on Wavelength Division Multiplexing and Cross-Correlation Estimation

In this paper, we propose a novel method to measure the frequency noise characteristics of narrow linewidth laser sources based on wavelength division multiplexing and cross-correlation estimation using two reference lasers. The delayed self-heterodyne structure is shared by the under-test laser (LUT) and the two reference lasers (LREF), and furthermore the cross-correlation process enables the proposed system immune to the environmental vibration. In experiments, frequency noise and linewidth distribution characteristic of the LUT are measured.