Linear AWG-based modulators

We numerically evaluate the performance of optical vectorial linear modulators, which consist of asymmetric power splitter, phase shifters and phase modulators (PM); 2^N-level quadrature amplitude modulated (QAM) signals are generated by using only N single-drive two-level (binary) RF signals. We also demonstrate that a proper architecture design, with phase and amplitude modulators, largely increases the constellation size. Finally, we show that a more compact layout can be achieved with an arrayed waveguide grating (AWG) configuration. The influence of the insertion losses, phase distortion and power imbalance are also investigated.