Low threshold operation of membrane buried heterostructure distributed feedback laser

Low threshold and single mode operation of 1.55 μm-wavelength GaInAsP/InP membrane buried heterostructure distributed feedback (BH-DFB) lasers consisting of deeply etched single-quantum-well wire-like active regions was demonstrated under room temperature CW optical pumping. A threshold pump power of 4.8 mW and a sub-mode suppression ratio (SMSR) of 39 dB were obtained for a 142 nm thick membrane with a cavity length of 120 μm and a stripe width of 2 μm. The corresponding threshold for current injection was roughly estimated to be 88 μA. The stop-band width was also observed to be 37 nm and an index-coupling coefficient of the grating structure was estimated to be 1140 cm^-1.