Single longitudinal mode distributed feedback double channel planar buried heterostructure 1.55 µm InGaAsP/InP lasers

The fabrication of single longitudinal mode (SLM) distributed feedback (DFB) InGaAsP/InP lasers emitting at 1.55µm using the double channel planar buried heterostructure (DCPBH) laser structure is reported. The distributed feedback configuration has the second order feedback grating etched directly upon the InP substrate before the first growth of the double heterostructure. These DFB-DCPBH lasers have CW threshold currents of 25 mA at 30°C and a threshold current temperature sensitivity (To) of 55 K. Single longitudinal mode operation between 15° and 75°C and mode suppression ratios as high as 30 dB have been obtained.