Photonic Sampler for mmWave Signals Up to 70 GHz Using a 1-GHz MLL and a Silicon PIC

Abstract

Modern RF communications require the digitization of narrow bandwidth signals modulated on very high frequency carriers which can be a challenge requiring high-frequency oscillators and mixers for downconversion which can add jitter and distortion while being costly to implement. This work presents a photonic bandpass RF-sampling system using a silicon-photonic PIC and a 1-GHz 10.5-fs-jitter mode-locked laser where the MLL is modulated with mmWave complex modulated signals using a silicon photonics Mach Zehnder modulator and received using a low bandwidth photodiode. The usage of a MLL plus a low bandwidth PD demonstrates photonic downconversion of complex QAM signals at millimeter-wave frequencies up to 70 GHz, without the use of a mixer and local oscillator.