Broadband and Power-Efficient Optoelectronic Transmitter Monolithically Integrated in a SiGe BiCMOS ePIC Technology

This paper presents a broadband and power-efficient monolithically integrated optoelectronic transmitter based on a segmented Mach-Zehnder modulator. The chip has been fabricated in the 250nm IHP SiGe BiCMOS ePIC monolithic process, combining both electronics and photonics on the same silicon substrate, including HBTs featuring <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{t} / f_{{\max }}$</tex> of 210/290 GHz and silicon depletion phase shifters. The designed modulator consists of 8-segments, each driven by a three stages amplfier, which delivers <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4 \mathrm{V}_{\text{pp}}$</tex> in order to achieve a sufficient extinction ratio, accordingly to the modulation efficiency of the modulator. Electro-optical small-signal measurements showed bandwidth of 45 GHz. Time-domain measurements showed NRZ data-rates up to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$64 \text{Gbit} / \mathrm{s}$</tex> from an overall power consumption of 450mW and a power efficiency of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$7.1 \text{pJ} / \text{bit}$</tex>, resulting in the most efficient Mach-Zehnder modulator based transmitter that can be found in the literature in a monolithic process.