Analytical expressions of linear and third-order nonlinear optical refractive index changes are obtained in P schl-Teller well using the density matrix formalism taking into account the intrasubband relaxation. Since there are two adjustable parameters κ and λ in the P schl-Teller well

the shape of the wells will change with the change of the parameters κ and λ

accordingly the linear and the third-order nonlinear refractive index will change with the para meters κ and λ. It is shown that the refractive index changes depends on the shape of the well

the tunnel bandwidth and the optical power. Numerical results are presented for a typical GaAs/AlGaAs P schl-Teller well.