Nonlinear optical absorption in bulk GaInAs/InP at room temperature

Abstract
We report cw measurements of band-gap resonant nonlinear absorption in bulk Ga0.47In0.53As/InP at room temperature. A tunable Co:MgF2 laser was used for these experiments. The nonlinear absorption coefficient α2 is determined by measuring saturation of the optical absorption, and from this the nonlinear refractive index n2 is calculated in the band-tail region. We find α2≊−6 cm W−1 at 1.67 μm and n2≊−4×10−5 cm2 W−1 at 1.69 μm. Within the band-tail region the nonlinear optical quality factor ‖n2/α‖ is found to lie between 0.9 and 1.8×10−8 cm3 W−1.