Nonlinear absorption of InN/InGaN multiple-quantum-well structures at optical telecommunication wavelengths
Résumé
We report on the nonlinear optical absorption of InN / InxGa1−xN (x=0.8, 0.9) multiple-quantum-well structures characterized at 1.55 µm by the Z-scan method in order to obtain the effective nonlinear absorption coefficient (α2) of the samples at high repetition rate. Saturable absorption is observed for the sample with x=0.9, with an effective α2~−9x103 cm /GW for the studied optical regime. For lower In content in the barrier, reverse saturable absorption is observed, which is attributed to two-photon absorption.