An analysis of cleaved coupled-cavity lasers

We present an analysis of (GaAl)As cleaved coupled-cavity (C
³
) lasers incorporating gain dependence on pumping and wavelength of both laser segments as well as the effects of spontaneous emission in the lasing diode section and the known dependence of file refractive index on carrier density. Our model allows us to analyze the physical origin of the experimentally observed variations in the lasing longitudinal mode number with the modulator laser section current. It also indicates a strong dependence of device behavior on the gap length and yields precise variations in threshold current with modulator current. In addition, the model predicts that in the vicinity of particular current values large (∼ 100 Å) wavelength shifts can be observed. These shifts could be useful in optical fiber communications multiplexing applications. Finally, results for C
³
lasers with sections of quite dissimilar length are presented and we note that these devices exhibit more erratic behavior than the lasers with sections of comparable length.