Fabrication and Performance Characteristics of 1.55microns InGaAsP Multiquantum Well Ridge Guide Lasers

We report the fabrication and performance characteristics of InGaAsP ridge waveguide lasers with multiquantum well (MQW) active layers emitting near 1.55microns. The active region has four active wells (1.55microns InGaAsP) and three barriers (1.3microns InGaAsP). The thicknesses of the active wells and the barrier layers are ~250angstroms. The 360micron-long lasers have threshold currents in the range 60-80 mA at 30C, external differential quantum efficiency ~25% at 30C, and T sub o ~70K. The modulation bandwidths of the lasers are ~1.5 GHz and they exhibit less frequency chirping than similar lasers with conventional double heterostructure (DH) active layer. Since frequency chirp limits the performance of high bit rate long haul fiber communication system at 1.55microns, we believe MQW lasers offer an advantage over conventional DH lasers.