State Univ Sao Paulo UNESP, Campus Sao Joao da Boa Vista, BR-13876750 Sao Joao Da Boa Vista, SP - Brazil
 Univ Prebiteriana Mackenzie, MackGraphe, BR-01302907 Sao Paulo, SP - Brazil
Número total de Afiliações: 4
Tipo de documento:
Applied Physics Letters;
JUN 18 2018.
Citações Web of Science:
We report on time-resolved pump and probe characterization of linear and nonlinear optical generation of free carriers in a silicon strip nano-waveguide at the 1550 nm communication band. Analytical expressions were developed to extract the carrier density averaged along the waveguide length from the measured free-carrier absorption for different input pump power levels. This allows us to discriminate the contributions from two-photon absorption (TPA) and single-photon absorption (SPA), obtaining TPA and SPA coefficients of (1.5+/-0.1) cm/GW and (1.9+/-0.1) m(-1), respectively. Our results reveal that the effective TPA within the waveguide is higher than the value reported for bulk silicon. In addition, we find that for the waveguide under test, the carrier generation via SPA plays an important role up to similar to 300 mW, and therefore, it must be taken into account to correctly assess free-carrier effects in silicon photonic devices. Published by AIP Publishing. (AU)