FPGA-driven random walk noise generation for tunable laser linewidth control

Abstract

We propose a novel approach for real-time generation of random walk noise. Our approach aims to generate natural laser phase noise and construct a linewidth tunable laser. By utilizing field- programmable gate array circuits and digital-to-analog converters, we generate noise that is subsequently combined with low-frequency analog noise. This combined noise is then fed into a lithium niobate phase modulator to emulate phase fluctuations. Our method facilitates accurate control over the laser linewidth spectrum, closely approximating actual noise characteristics.