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arXiv · 1809.00237

Temperature dependence of the Kerr nonlinearity and two-photon absorption in a silicon waveguide at 1.55μm

Gary F. Sinclair·Nicola A. Tyler·Döndü Sahin·Jorge Barreto·Mark G. Thompson
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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 at a wavelength of 1.55 μm. The two-photon absorption coefficient is calculated from the power dependent transmission of a 4.9 ps pulse. We observed a nearly two-fold decrease in the two-photon absorption coefficient from 0.76 cm/GW at 300K to 0.42 cm/GW at 5.5 K. The Kerr nonlinearity is inferred from the self-phase modulation induced spectral broadening of the transmitted pulse. A smaller reduction in Kerr nonlinearity from 5.2E-18 m^2/W at 300 K to 3.9E-18 m^2/W at 5.5 K is found. The increased ratio of Kerr to absorptive nonlinearity at low temperatures indicates an improved operation of devices that make use of a nonlinear phase shift, such as optical switches or parametric photon-pair sources. We examine how the heralding efficiency of a photon-pair source will change at low temperature. In addition, the modelling and experimental techniques developed can readily be extended to other wavelengths or materials of interest.

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Gary F. Sinclair, Nicola A. Tyler, Döndü Sahin, Jorge Barreto, Mark G. Thompson. 2018-09-01. Temperature dependence of the Kerr nonlinearity and two-photon absorption in a silicon waveguide at 1.55μm. https://doi.org/10.1103/physrevapplied.11.044084

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