Low Power InP-Based Monolithic DFB-Laser IQ Modulator With SiGe Differential Driver for 32-GBd QPSK Modulation

Abstract

An optical transmitter incorporating a monolithically integrated laser and a traveling wave electrode in-phase and quadrature modulator is presented. A co-designed SiGe differential driver was co-packaged for highest quality push-pull modulation. With only 0.1-dB coupling loss between the laser and the modulator, and a low modulator switching voltage the transmitter power consumption was 1.1 W, which fits the CFP4 (analog coherent optics) ACO module overall budget of 6 W. Without DSP for precompensation, FEC or equalization, 32 GBd QPSK with 3 V pp driving voltage and an error vector magnitude of <;10% are presented. Operation with an optical signal-to-noise ratio larger than 14 dB is achieved before breaking the hard decision forward error correction threshold (3.8 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> ).