Doping level and type of GaInP saturable absorbing layers for realizing pulsating 650-nm-band AlGaInP laser diodes

On AlGaInP laser diodes, the doping level and type of GaInP saturable absorbing (SA) layers suitable for self sustained pulsation are clarified. Optical properties of n- and p-type GaInP quantum wells (QWs) have been evaluated by means of time-resolved photoluminescence (TRPL) spectroscopy. As the doping level becomes higher, the recombination lifetime becomes shorter, and it can be reduced to 1.1 ns at our highest doping level (1=2/spl times/10/sup 18/ cm/sup -3/). For highly doped n-type QW, a PL peak energy shift as large as 26 meV is observed by high-density excitation. Highly doped p-type SA layer is suitable for self-sustained pulsating laser diodes, because it offers short recombination lifetime and no Burstein shift under highly excited condition.