Abstract

Recent all-optical switching experiment have shown the usefulness of AlGaAs used below half the band gap.^1–3 This spectral region is useful because the two photon absorption (2PA) vanishes below half the band gap, and that 2PA was shown to be detrimental to all-optical switching.⁴ However, the three photon absorption (3PA) becomes the limiting factor for nonlinear guided wave when the influence of the 2PA can be neglected.⁵ The previously measured value included some absorption by free carriers that were generated by 2PA.² Such a process has the same behavior versus intensity as 3PA. In the present experiment the two photon absorption is negligible, therefore only the 3PA coefficient has been measured. We will show that AlGaAs satisfies the figures of merit and hence is a prime candidate for the study of nonlinear guided wave phenomena at 1550 nm.

© 1993 Optical Society of America