Nonlinear Temperature Dependence of Resonant Pump Wavelengths in Optical Pumping Injection Cavity Lasers

Type-II W optical pumping injection cavity lasers emitting ~3 μm at room temperature are pumped resonantly by tuning with an optical parametric oscillator. The resonance pump wavelength consistently is found to vary quadratically with temperature. Linear corrections to the lattice constant and index of refraction with temperature do not adequately account for this trend. Using multilayer reflectivity modeling, this nonlinear temperature dependence is attributed to gain-induced changes in the refractive index of the active region and spacer layers that result from the increase in optical pumping intensity with increasing temperature.