All-optical refractive nonlinearity in a passive InGaAs/InAlAs multiqu
antum well waveguide is evaluated for TE and TM modes at 1.55 mum wave
length and room temperature. A quarter wavelength change in the optica
l path length is observed at an input pump light power of 6.5 mW for 1
.47 mum wavelength in a 960 mum long device. Nonlinear refractive inde
x n2 is evaluated to be -1.2x10(-6) and -0.5x10(-6)cm2/W for the TE an
d the TM modes, respectively.