Polarization-controlled operating point adjustment for optical electric field sensors in optical frequency comb undersampling systems

Optical frequency comb (OFC) undersampling systems enable rapid, high-precision monitoring of ultra-wideband electromagnetic environments. However, the operating point of the optical electric field sensor (OEFS) in such systems cannot be controlled through conventional techniques such as bias circuits or wavelength tuning, resulting in compromised sensitivity and a degraded dynamic range. To address this limitation, we propose a polarization-control-based method for OEFS operating point adjustment. This method tunes the operating point by varying the power ratio between the TM and TE modes in the light incident on the sensor. The theoretical principles underlying this approach are analyzed and experimentally validated. Results indicate that, compared to operation without polarization control, the implementation of our method improves the sensor's sensitivity by 12.73 ± 1.05 dB, increases the linear dynamic range (LDR) by 13.66 dB, and enhances the spurious-free dynamic range (SFDR) by 18.78 dB.