Infrared injection lasers with emission wavelength between 2-5 μm find application in optical communication systems using low-loss fluoride fibers, remote sensing through atmospheric window, gas analysis, and molecular spectroscopy. InAsPSb, which can be grown lattice-matched to InAs, has refractive index decreasing with increasing bandgap and can be grown by liquid-phase epitaxy despite the existence of a large miscibility gap. Double heterostructure lasers (DHL) can be realized by using the same alloy with different solid compositions for the active and cladding materials. InAs DHL with InAsPSb cladding cannot operate higher than 150 K, however, similar to that for InAs homojunction lasers. Our theoretical study shows that the direct limiting factor of these InAs DHL is carrier leakage. If we reduce the carrier leakage by using AlAsSb as cladding, for example, the threshold current density is reduced to that which is limited by Auger recombination.
© 1991 Optical Society of AmericaPDF Article