Direct measurements of large near-band edge nonlinear index change from 1.48 to 1.55 μm in InGaAs/InAlGaAs multiquantum wells

Direct picosecond measurements of nonlinear refractive index change and nonlinear absorption in In0.530Al0.141Ga0.329As/In0.530Ga0.470As multiquantum wells in the range 1480-1550 nm are reported. Large low-threshold nonlinear index changes are found: Deltan of up to 0.14 with figure of merit of 1.38 at a fluence of 116 muJ/cm(2). The index-change-over-absorption figure of merit, F, is greater than unity over much of the spectrum, pointing to the prospective applicability of the materials studied to nonlinear switching devices. (C) 2003 American Institute of Physics.