Wavelength dependence of characteristics of 1.2-1.55 mu m InGaAsP/InP p-substrate buried crescent laser diodes

Laser diodes with the p-substrate buried-crescent structure have been fabricated for the 1.2-1.55- mu m wavelength region. The dependence of laser characteristics on wavelength has been measured. Up to 70 degrees C, the increasing rates of the threshold current with temperature are similar, while, above 70 degrees C, a shorter-wavelength laser shows a larger increasing rate. At the same full width at half maximum of the far-field pattern perpendicular to the junction plane, the external differential quantum efficiency of the 1.55- mu m laser diode is only 10% smaller than that of the 1.3- mu m laser. The absorption loss coefficients in the active layer of the 1.2-, 1.3-, and 1.55- mu m laser are estimated to be 26, 34, and 73 cm/sup -1/, respectively.<>