InGaAsP distributed feedback multiquantum well laser.

The fabrication and performance characteristics of 1.3micron InGaAsP distributed feedback (DFB) lasers with multiquantum well (MQW) active layers are reported. The lasers are of the double channel planar buried heterostructure type and utilize a second order grating with a periodicity of ~3900 angstroms for frequency selective feedback. The lasers have threshold currents in the range 25-35 mA at 30C and external differential quantum efficiencies of 0.2 mW/mA/facet at 30C. The temperature dependence of threshold current is characterized by a T(0) value of 95K - 100K. The lasers have been operated to an output power of 19 mW in a single frequency. The measured dynamic linewidth under modulation is a factor of 2 smaller than that for regular double heterostructure lasers. The lower temperature dependence of threshold current and smaller dynamic linewidth makes real index guided InGaAsP DFB MQW active layer lasers attractive for many system applications.