Low-Threshold Strained-Layer InGaAs Ridge Waveguide Lasers

Strained-layer InGaAs graded-index separate confinement heterostructure single-quantum-well (SQW) lasers have been fabricated. The threshold current dependence on cavity length using a 150- µm-wide broad contact laser yielded a transparency current of 49 A/cm 2 and a differential gain coefficient of 10.8 cm/A, values which are both superior to those of conventional GaAs SQW lasers. A CW threshold current of fabricated 3- µm-wide ridge waveguide lasers was reduced to 2.8 mA by HR-HR coating at a lasing wavelength of 972 nm.