GaInAsP/InP distributed reflector lasers consisting of deeply etched vertical gratings

Abstract

Deep-etching technology, which is a very simple fabrication process and requires only one lithography and one etching step without any regrowth, is applied to realize 1.5-1.55 mum wavelength GaInAsP/InP vertical grating (VG) distributed reflector (DR) lasers, which consist of a distributed feedback (DFB) region with the VG and a high-reflectivity distributed Bragg reflector (DBR) region. First, the coupling coefficient of the VG is theoretically estimated and fundamental lasing characteristics of the VG-DR lasers are investigated. Then, the fabrication process of the VG-DR lasers and the experimentally achieved fundamental lasing characteristics are given. A threshold current of 12.4 mA and a differential quantum efficiency of 42% from the front cleaved facet are achieved for a 220-mum-long and 5-mum-wide device. A submode suppression ratio (SMSR) of 33 dB at a bias current of 2.4 times the threshold is obtained.