Highly Nondegenerate Two-Photon Absorption in Silicon Wire Waveguides

This is the authors' abstract. We don't add key points for this paper.

Nondegenerate two-photon absorption is important for integrated, broadband nonlinear optics, and has been exploited for $e.g.$ sensitive midinfrared photodetectors of direct-band-gap semiconductors. However, little is known about nonlinear absorption in semiconductors with i00exn00exd00exi00exr00exe00exc00ext band gaps, such as silicon. This study uses the nonlinear interaction between short pulses to probe two-photon absorption and phase modulation in silicon-wire waveguides. While dispersion cannot be neglected, nonlinear phase modulation surprisingly may not change much over a very wide wavelength range. This could impact supercontinuum and frequency-comb generation, or all-optical signal manipulation.