Self-sustained pulsation at 65 °C through reduced carrier overflow in AlGaInP laser diodes

Self-sustained pulsation at 65 degrees C under continuous-wave operation was obtained in AlGaInP laser diodes with a saturable-absorbing layer in part of the p-type cladding layer. The carrier overflow was significantly reduced to enable high-temperature performance by increasing the number of well layers in the active layer to four and increasing the compressive strain of the active layer (epsilon(act) = +0.5%). The effect of the carrier overflow on self-sustained pulsation was investigated by analyzing the lasing spectrum and lasing polarization. The large amount of luminescence from the saturable-absorbing layer demonstrated that excessive carrier overflow at high temperature prevents the saturable absorbing layer functioning as an absorber.