EXCITON-INDUCED ENHANCEMENT OF OPTICAL WAVE-GUIDE CONFINEMENT IN (ZN,CD)(SE,S) QUANTUM-WELL LASER HETEROSTRUCTURES

Room-temperature waveguide properties have been studied experimentally in ZnSe-based multiple-quantum-well laser structures. The spectra of waveguide transmission show distinct spectral features associated with heavy- and light-hole quantum well excitons. Refractive index dispersion in the multiple-quantum-well region is derived from interference spectra measured in short waveguide samples. The refractive index increases with approaching the exciton resonances, resulting in perfect confinement and low losses of the fundamental TE waveguide mode in a narrow spectral region below the heavy-hole exciton resonance energy. The spectra of laser generation have been measured under the conditions of optical pumping, showing the position of the lasing line to correlate with the spectral region of the waveguide transparency.