A 16-32GHz RF Photonic Front-End with 22nm CMOS Driver and Silicon Travelling-Wave Mach-Zehnder Modulator

Analog photonic links that leverage silicon photonic components offer potential advantages for building future wireless communication systems. A wideband electrical front-end circuit and a high speed electro-optic modulator are essential parts of the photonic receiver links. This paper presents a co-integrated 16-32GHz front-end link with an electrical driver in a 22nm CMOS FD-SOI process and a silicon photonic travelling-wave Mach-Zehnder modulator (TW-MZM) in a 220nm SOI process. A Magnetically-coupled resonator technique is adopted to realize wideband impedance matching network and a stack-FET structure is utilized for higher supply voltage operation, providing 13dBm output power from the driver. In the TW-MZM, a slow-wave transmission line electrode is implemented to improve its bandwidth by impedance and velocity matching. The CMOS and silicon photonic chips are co-designed considering the bond-wire and input impedance of TW-MZM. The calculated spurious free dynamic range (SFDR) of the link with a grating coupler is 89
$dB*Hz^{(2/3)}$
and it is possible to achieve 105
$dB*Hz^{(2/3)}$
using a lower-loss edge coupler.