A 15–25-GHz Dual-Differential Photonic Front-End With Silicon Traveling-Wave Mach–Zehnder Modulator and 22-nm CMOS Driver

An analog RF photonic front-end utilizing a dual-differential (DD) driving scheme is presented that features a 22-nm FD-SOI CMOS driver co-integrated with a silicon DD traveling-wave Mach–Zehnder modulator (DD-TW-MZM). This driving scheme offers an efficient and compact solution that enhances modulation depth by 6 dB at the cost of increased routing complexity. The driver incorporates a compact power splitter and an output routing network that enables the DD driving configuration. Slow wave (SW) electrodes and phase recovery loops are utilized in the DD-TW-MZM design to optimize electrooptic performance. Additionally, an$LC$input matching network (IMN) co-designed with bond wire inductances is implemented on the silicon photonic integrated circuit (Si-PIC) to optimize matching with the CMOS driver. Implemented with both 1- and 2-mm long DD-TW-MZM variations, the proposed integrated front-end achieves a wide 15–25-GHz bandwidth and 11.3% EVM at 3 Gb/s 16-QAM operation with the 1-mm MZM.