Spectrally Pure W-Band RF Carrier Generation with Packaged Silicon Photonics Circuit

A packaged silicon photonics radio-frequency (RF) synthesizer operating in the millimeter (mm-) wave band suitable for clock signal distribution in b5G/6G radio access networks is realized and experimentally characterized. The assembly include a photonic integrated circuit (PIC) acting as a frequency multiplier for a local oscillator (LO) reference at microwave frequencies and a printed circuit board (PCB) hosting a custom bias tee designed to provide a wideband matching condition over more than 6 GHz around 20 GHz for the input LO signal and supporting high power levels for efficient frequency multiplication operation. Phase noise (PN) measurements performed on a 100 GHz generated RF carrier via five-fold multiplication of a LO wave at 20 GHz indicate a low PN of -97 dBc/Hz at 10 kHz from the carrier with a small excess timing jitter of less than 2 fs with respect to the LO signal, making the circuit operating nearly as an ideal frequency multiplier.