Evaluation of GaAs/${\mathrm{Al}}_{0.3}$${\mathrm{Ga}}_{0.7}$As multiple-quantum-well waveguides for pulsed squeezed light generation

We have measured the nonlinear refractive index ${\mathit{n}}_2$ and two-photon absorption coefficient β in GaAs/${\mathrm{Al}}_{0.3}$${\mathrm{Ga}}_{0.7}$As multiple-quantum-well waveguides in the band tail region about 45 meV below the n=1 heavy hole exciton absorption line. At 883 nm we find that β=1.9×${10}^{\mathrm{-}8}$ cm ${\mathrm{W}}^{\mathrm{-}1}$ and that ${\mathit{n}}_2$≊-1×${10}^{\mathrm{-}12}$ ${\mathrm{cm}}^2$ ${\mathrm{W}}^{\mathrm{-}1}$. The linear loss coefficient is measured to be 6.3 ${\mathrm{cm}}^{\mathrm{-}1}$ at the same wavelength. Based on these values, we estimate that up to 4.5 dB pulsed squeezing is possible.