High performance coherent optical spectrum analyzer based on a low-pass filter and phase noise power analysis

The coherent optical spectrum analyzer (COSA) has attracted growing attention as the advancement of dense wavelength division multiplexing (DWDM) systems and precision optical measurement techniques continues to elevate the requirements for high-resolution spectral characterization. To address the mutual constraints of wavelength resolution and power uncertainty faced by traditional coherent spectrum analyzers, here, we propose a spectral reconstruction scheme based on a low-pass filter and phase noise power analysis. The proposed COSA system achieves decoupling between resolution and power uncertainty in spectral reconstruction by employing repeated measurements, and effectively reducing power uncertainty through this repetitive sampling methodology.