Evaluation of Optical Gain Properties of GaInAsP/InP Compressively Strained Quantum-Wire Lasers

The gain spectral characteristics of 1.5-µm-wavelength GaInAsP/InP compressively strained quantum-wire lasers with wire widths of 20 nm and 25 nm, fabricated by electron-beam lithography and two-step organometallic vapor phase epitaxial growth, were measured at a temperature of 100 K and were compared with those of quantum-film lasers fabricated on the same wafer. It was found, for the first time, that the material gain spectrum of quantum-wire lasers is narrower than that of the quantum-film laser. Moreover, the origin of this narrow gain spectral property of the quantum-wire lasers was theoretically investigated and explained in terms of the twofold longer intraband relaxation time in the quantum-wire structure.