Enhancement of the Modulation Dynamics of an Optically Injection-Locked Semiconductor Laser Using Gain Lever

The modulation response of an optically injected gain-lever semiconductor laser is studied for the first time using small-signal analysis of a rate equation model. Calculations show that a gain-lever laser operating under medium to strong optical injection provides a unique and robust configuration for ultralarge bandwidth enhancement. Modulation bandwidths above nine times the relaxation oscillation frequency of the free-running laser can be reached using injection-locking conditions that are reasonable for practical applications. This theoretical work is of prime importance for the development of directly modulated broadband optical sources for high-speed operation at 40 Gb/s and beyond.