Linewidth narrowing and phase locking of quantum-dot mode-locked lasers employing single- and dual-mode injection locking

Optical pulse sources with narrow oscillation linewidth and optical phase-controllability are important as the signal and local light sources for high-speed coherent communication. Quantum-dot CW lasers have shown very stable optical injection locking characteristics, with no instabilities observed at low detuning [1]. This observation suggests that QD-MLL performance could be further improved and controlled though optical injection locking and in particular that dual mode injection for remote coherent receivers should be investigated for this medium [2]. In this paper we investigate in-band single- and dual-tone injection. We show tunability of the slave laser optical spectrum via the master wavelength, significant linewidth narrowing and phase locking of the injected QD-MLL to the master laser.