High Sensitivity Photodetector for Optical Undersampling Microwave Frequency Measurement

To achieve high-sensitivity electric field signal measurement in an optical frequency comb undersampling real-time microwave measurement system, this article designs a high-saturation optical power balanced photodetector suitable for the system. Testing indicates that this photodetector supports pulsed optical power injection up to 5 dBm, resulting in a 21 dB improvement in SNR compared to single-ended detection and achieving a sensitivity better than 1 m V/m.