Abstract
We measure the temperature dependence of the two-photon absorption and optical Kerr nonlinearity of a silicon waveguide over a range of temperatures from 5.5 to 300 K. Measurements are taken at a wavelength of 1.55 in the technologically important telecom band. We observe a near halving (45% reduction) of the two-photon absorption coefficient at low temperature, whereas a smaller reduction in the Kerr nonlinearity of 25% is found. The increased ratio of Kerr to absorptive nonlinearity at low temperatures indicates an improved operation of integrated photonic devices that make use of a nonlinear phase shift, such as optical switches or parametric photon-pair sources. As an example, we examine how the heralding efficiency of a photon-pair source will change at low temperatures and predict a modest improvement in source performance. In addition, the modeling and experimental techniques developed can readily be extended to other wavelengths or materials of interest.
- Received 11 September 2018
- Revised 19 February 2019
DOI:https://doi.org/10.1103/PhysRevApplied.11.044084
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