InGaAs/InP graded-index quantum well lasers with nearly ideal static characteristics

Abstract

We have examined static properties of step and continuously graded single and multiple quantum well InGaAs/InP lasers grown by atmospheric pressure metalorganic vapor phase epitaxy. Systematic changes in the band gap of InGaAsP waveguide layers have resulted in lasers with low threshold current (<10 mA), high quantum efficiency (26% per facet) and power output (∼70 mW), and the effective loss of 2–5 cm−1. We show that the changes in threshold current in short lasers can be explained by a switch from the n=1 to n=2 level. The level switching results in a very flat and wide (>1000 Å) gain profile.