16-level quadrature amplitude modulation by monolithic quad-parallel Mach-Zehnder optical modulator

Abstract
A monolithically-integrated quad-parallel Mach-Zehnder optical modulator has been fabricated. 3 and 6 dB electro-optical bandwidths of Mach-Zehnder structures embedded in the modulator were evaluated as 22 and 36 GHz, respectively. By using the monolithic optical modulator, a 10 Gbaud 16-level quadrature amplitude modulation (QAM) signal was successfully obtained.