Evaluation of Performance Enhancement of Optical Multi-Level Modulation Based on Direct Modulation of Optically Injection-Locked Semiconductor Lasers

The performance of optical M-level (multi-level) amplitude shift keying (ASK) modulation is improved by directly using modulated optically injection-locked (OIL) semiconductor lasers. direct free-running and OIL lasers evaluated compared theoretically based on coupled-rate equation. We have found that can significantly improve the in terms signal eye opening Q-factor. Additionally, we Q-factor increases even more negative frequency detuning range due to its dependence locking parameters.