Experimental and theoretical studies on the high frequency dynamics of (GaAl)As semiconductor lasers center on three main areas: 1) analog modulation response of laser diodes; 2) pulse (pulse code modulation) response of laser diodes and 3) generation and quenching of intensity pulsations in laser diodes coupled to external cavities.
The basic analog modulation and transient characteristics of injection lasers with various structures are studied and compared. The basic limitations on ultrahigh frequency ( > 5GHz) modulation of lasers are considered. Self-pulsations in injection lasers are studied and their interaction with external cavities are clarified. These studies lead to the quenching of self-pulsation and ultra-short short pulse generation in laser diodes by coupling to an external cavity. A novel external fiber resonator is introduced for this purpose. Pattern effects in pulse code modulation of injection lasers are studied and a bipolar pulsing scheme devoid of the above effect is described. The transverse mode shift in a transverse junction laser under ultrashort electrical pulse excitation is investigated. Finally, the frequency response of superluminescent lasers (lasers without mirrors) is analysed.
