Design of a novel Equalizer-Driver with 3.7 Vpp diff linear output swing and 16 dB of peaking gain at 55 GHz for 64 GBd PAM-4 optical communication transmitters

Abstract

This paper introduces a novel Equalizer-Driver that combines equalizing and driving functionalities in a single function aimed at increasing the bandwidth and energy efficiency of electro-optical (E/O) transmitters. Implemented in III-V Lab’s 0.7-µm InP DHBT technology, the Equalizer-Driver exhibits in full EM-circuit co-simulation 13 dB of differential gain (Sd2d1) at 10 MHz and 16 dB of peaking gain at 55 GHz, for a total intrinsic -3 dB-bandwidth over 100 GHz. Transient simulations show it is able to provide an equalized and amplified 3.7-Vpp diff linear output signal in PAM4 at 64 GBd, from an input signal filtered by a Bessel filter with a 17-GHz -3 dB-bandwidth. Consuming 1.2 W at its maximum 3.7-Vpp diff linear output swing, it is well suited for bandwidth limited optical transmitters at 64 GBd and beyond.