Abstract

Multiple-quantum-well (MQW) lasers are favored over bulk-active double-heterostructure (DH) lasers for some applications because MQW lasers theoretically have a smaller cw linewidth and frequency chip owing to their smaller linewidth enhancement factors a and have a higher bandwidth owing to their large differential gains.^1,2 We report the fabrication and performance of 1.55-μm MQW distributed-feedback (DFB) lasers that have the aforementioned characteristics. The MQW-DFB lasers are grown by low-pressure metal-organic chemical vapor disposition (LP MOCVD)³ and are based on the capped-mesa buried heterostructure (CMBH)⁴ The active layer of the lasers includes quantum wells of InGaAs and barriers of InGaAsP. Both four-well and six-well structures are examined. The devices are 500-μm long and have a low-reflectivity coating (<l%)on the output facet and a high reflectivity coating (~65%) on the back facet.

© 1991 Optical Society of America