Intensity Noise Suppression in Photonic Detector Systems for Spectroscopic Applications

Spectral measurement technology has found extensive applications across a diverse range of fields, including chemical analysis, environmental monitoring, precise measurement, and laser frequency stabilization. However, the accuracy of spectral measurement results is often constrained by the power noise and frequency jitter inherent in the light source. In contrast to the traditional differential amplification method for acquiring spectral signals, our study introduces a novel approach. By employing a power correction quotient, we effectively suppress common-mode noise. Additionally, we introduce a novel composite differential method that, in theory, is capable of performing closed-loop processing on spectral signals to stabilize the laser frequency. This innovative method not only constructs a stable laser source but also yields high-quality spectral signals simultaneously. In an experiment involving iodine molecule absorption spectroscopy, the algorithm we propose demonstrated remarkable efficacy in mitigating distortions caused by modulated signals and significantly enhanced the signal-to-noise ratio. This algorithm is versatile and can be applied to the signal processing of any spectral signal sensor that employs dual-path light.