Silicon Photonics Circuit for Tunable Low-Phase Noise RF Generation up to W-band

This paper reports on the performance of a circuit monolithically integrated in Silicon-on-insulator (SOI) platform, employed for photonics-based carrier radiofrequency multiplication. An applied reference clock at 18.5 GHz is successfully multiplied up to 92.5 GHz (fivefold) with low additional phase noise. The SOI circuit includes a high-speed electro-optic phase modulator employed for optical spectral comb (OSC) generation and a thermally tunable distributed feedback resonator filter for selecting one of the OSC mode. Beating of the input laser mode with the mode selected by the filter into a high-speed photodiode generates the target output carrier frequency. By suitably tuning the clock frequency and the integrated optical filter, the solution permits reconfigurable frequency generation up to W-band and, potentially, beyond. Experimental results demonstrate that the generated multiple carrier frequencies exhibit phase noise performance comparable with the one of the clock source.