Monolithically Integrated Optoelectronic Transmitter based on Segmented Mach-Zehnder Modulator in EPIC 250 nm BiCMOS Technology

This paper presents a monolithically integrated optoelectronic transmitter based on a segmented Mach-Zehnder modulator. The chip is fabricated in the 250nmSiGe BiCMOS SG25H5 EPIC technology developed at IHP, a silicon-photonic technology combining 0.25 $\mu$m CMOS, high-performance npn HBTs (featuring $\mathrm{f}_{\mathrm{t}}$/f max of 210/290 GHz), and a full photonic device set for C/O-band. The chip includes a linear electrical driver, a 5 segments Mach-Zehnder modulator, for a total phase shifter length of 2 mm. Electro-optical time-domain measurements demonstrate open eye diagrams up to 44 Gb/s NRZ. The electro-optical bandwidth is 35 GHz, while the power consumption is 500mW, resulting in a power efficiency of 11.3 pJ/bit at 44 Gb/s. The reported transmitter results in a compact and power efficient solution compared to others in a silicon monolithic approach and comparable to hybrid solutions, within the higher 3 dB electro-optical bandwidth that can be found in the literature.