Coherent detection performance of Gaussian-Schell model pulses: impacts of temporal coherence, pulse width, and optical path difference

This paper theoretically investigates the coherent laser detection performance for partially temporally coherent pulses modeled by the Gaussian-Schell model (GSM), in conjunction with a continuous-wave (CW) local oscillator (LO) beam with a Gaussian spectral profile. A theoretical framework for coherent detection of partially temporally coherent pulses is established. Theoretical analysis and numerical simulations demonstrate that the signal-to-noise ratio (SNR) and spectral linewidth of the coherent detection signal critically depend on temporal coherence, pulse width, and optical path difference (OPD) between the signal and LO beams. Our findings elucidate fundamental physical mechanisms governing coherent detection of partially temporally coherent pulses and provide essential guidelines for optimizing system parameters in practical applications such as remote sensing and free-space communication. Furthermore, the framework extends delayed self-heterodyne interferometry (DSHI), originally developed for continuous-wave (CW) lasers, to characterize the temporal coherence for pulsed lasers.