Real-Time Phase-Noise-Tolerant 2.5-Gb/s Synchronous 16-QAM Transmission

The 2.5-Gb/s coherent 16-quadrature amplitude modulation data is optically transmitted over 75 km and synchronously received by self-homodyning in a real-time in-phase and quadrature receiver, with bit-error ratio below forward-error correction threshold. To this purpose, a phase-noise-tolerant hardware-efficient feedforward carrier recovery was implemented.