Low threshold and high power output 1.5 μm InGaAs/InGaAsP separate confinement multiple quantum well laser grown by chemical beam epitaxy

Abstract
We have demonstrated the first successful preparation of InGaAs/InGaAsP multiple quantum well (MQW) lasers grown by chemical beam epitaxy. The broad‐area threshold current densities of standard (not graded index) separate confinement heterostructure (SCH) MQW lasers were as low as 860 and ∼590 A/cm2 for cavity lengths of 500 and 1500–3500 μm. Such values are similar to those obtained from MQW wafers employing the more advanced graded index SCH(GRIN‐SCH) grown by metalorganic vapor phase epitaxy. Buried‐heterostructure lasers also have similar threshold currents, i.e., 25–40 mA for 300–1500 long cavities. Pulsed and cw output power at 1.57 μm as high as 216 and 140 mW were obtained from 1‐mm‐long buried‐heterostructure lasers having antireflection and high reflection coatings of ∼5% and ∼85%. The layer thickness uniformity is better than ±1% across a 2‐in.‐diam wafer.