A flexible multi-16QAM transmitter based on cascaded dual-parallel Mach-Zehnder modulator and phase modulator.

In this paper, we propose a novel and flexible 16-quadrature amplitude modulation (16QAM) transmitter based on cascaded dual-parallel Mach-Zehnder modulator (DPMZM) and phase modulator (PM). The proposed transmitter is able to generate three types of 16QAM signals: square 16QAM, star 16QAM and four-amplitude-four-phase-16-QAM (FAFP-16QAM). The feasibility of the transmitter is verified through experiment, 20-Gb/s eye diagrams of the 16QAM signals are obtained. In order to evaluate the performances of the 16QAM signals, simulations are also conducted using VPI Transmission Maker, clear constellations of 40-Gb/s 16QAM signals are achieved by coherent detection. [ABSTRACT FROM AUTHOR]