Modulation and dynamical characteristics of high-speed semiconductor lasers subject to optical injection

Experimental study on the dynamical and modulation characteristics of an optically injected semiconductor laser is presented in this dissertation. The dynamics of the laser system is identified and mapped. The characteristics of the period-one oscillation is discussed, where the tunability of period-one oscillation sideband in frequency and in magnitude is found and the shift of the principal oscillating frequency is observed. Through an optical probing method, a 35-GHz intrinsic bandwidth for direct modulation is experimentally achieved under stable injection locking. Operating conditions are discussed for even larger bandwidth enhancement and better modulation response. The mechanism of bandwidth enhancement is attributed to, based on the experimental observation, the dynamical competition between the external injection signal and the preferred cavity resonance. Harmonic distortions due to the inherent nonlinearity of the laser are discussed. Significant reduction in harmonic distortion is observed through the use of the injection locking method.