Dual frequency comb assisted analog-to-digital conversion

Photonic analog to digital conversion offers promise to overcome the signal-to-noise ratio and sample rate trade-off in conventional analog to digital converters (ADCs), critical for modern digital communications and signal analysis. We propose using phase-stable dual frequency combs with a fixed frequency spacing offset to downconvert spectral slices of a broadband signal and enable high-resolution parallel digitization. To prow the concept of our proposed method, we demonstrate the detection of a 10 GHz subcarrier modulated (SCM) signal using 500 MHz bandwidth ADCs by optically converting the SCM signal to 10 1 GHz bandwidth signals that can be processed in parallel for full signal detection and reconstruction. Using sinusoidalwave-based standard ADC testing, we demonstrate a spurious-free dynamic range of >45 dB and signal-tonoise-and-distortion of >20 dB, limited by the receiver front-end design. (C) 2019 Optical Society of America