Analysis of intensity noise in a dual-comb linear optical sampling ranging system

Dual-comb ranging (DCR) has emerged as a representative method for absolute distance measurement; however, its precision remains susceptible to intensity noise in practical implementations. This study establishes a comprehensive theoretical model for intensity noise in a linear optical sampling DCR system. The model is composed of two parts: one focuses on the influence of the system's hardware parameters on the signal-to-noise ratio (SNR) of dual-comb interferograms, and the other investigates the impact of key algorithm parameters on ranging precision. We design corresponding experiments to validate the model. A scheme is proposed to mitigate photodiode detector saturation based on the model, and the ranging precision is improved to 0.12 µm at a 2 ms refresh rate. Finally, the study proposes evaluation criteria for assessing DCR systems under intensity noise, enabling comparison of noise levels across different systems. This work provides theoretical insights for designing DCR systems and improving ranging precision.