Influence of heating of the active region in InGaAsP/InP injection lasers on their spectral characteristics

Spectral and spatial characteristics of the output of InGaAsP/InP separate-confinement double heterostructure laser are investigated. The measurements are performed in quasicontinuous and continuous pumping regimes at room temperature. These lasers are shown to be spatially single-mode over the entire working range of currents. The broadening of the longitudinal modes under quasicontinuous pumping is attributed to heating of the active region of the lasers. The pump pulse duration at which heating of the active region of the lasers can be neglected is estimated.