RESUMEN
We report a nonlinear signal processing system based on a SiGe waveguide suitable for high spectral efficiency data signals. Four-wave-mixing (FWM)-based wavelength conversion of 10-Gbaud 16-Quadrature amplitude modulated (QAM) and 64-QAM signals is demonstrated with less than -10-dB conversion efficiency (CE), 36-dB idler optical signal-to-noise ratio (OSNR), negligible bit error ratio (BER) penalty and a 3-dB conversion bandwidth exceeding 30nm. The SiGe device was CW-pumped and operated in a passive scheme without giving rise to any two-photon absorption (TPA) effects.
RESUMEN
We characterize the nonlinear optical response of low loss Si(0.6)Ge(0.4) / Si waveguides in the mid-infrared between 3.3 µm and 4 µm using femtosecond optical pulses. We estimate the three and four-photon absorption coefficients as well as the Kerr nonlinear refractive index from the experimental measurements. The effect of multiphoton absorption on the optical nonlinear Kerr response is evaluated and the nonlinear figure of merit estimated providing some guidelines for designing nonlinear optical devices in the mid-IR. Finally, we compare the impact of free-carrier absorption at mid-infrared wavelengths versus near-infrared wavelengths for these ultra-short pulses.
RESUMEN
We have investigated the nonlinear optical response of low loss Si(0.6)Ge(0.4) / Si waveguides in the mid-infrared wavelength range from 3.25- 4.75µm using picosecond optical pulses. We observed and measured the three and four-photon absorption coefficients as well as the Kerr nonlinear refractive index. The dynamics of the spectral broadening suggests that, in addition to multiphoton absorption, the corresponding higher order nonlinear refractive phenomena also needs to be included when high optical pulse intensities are used at mid-infrared wavelengths in this material.