Refractive Index, Absorption Coefficient, and Photoelastic Constant: Key Parameters of InGaAs Material Relevant to InGaAs-Based Device Performance

A theoretical study has been carried out to evaluate key parameters of In_xGa_1-xAs material at energies below the direct band edge. The spectral dependence of refractive index, absorption coefficient, and photoelastic constants are evaluated for the whole composition range in In_xGa_1-xAs material on the basis of simplified models of the interband transitions. The results obtained from the present study are compared with the experimental results and found to be in good agreement. We have also evaluated refractive-index steps between In_xGa_1-xAs and GaAs materials for variety of waveguiding device applications.