Nonreciprocal propagation in a non-Hermitian silicon photonic coupler employing graphene saturable absorption
Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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Published online: 20 August 2020
We present the concept, analysis and design of a nonreciprocal system of coupled nonlinear waveguides, operating at the near infrared. We exploit the spatial asymmetry induced by the exceptional points of a non-Hermitian coupler which, combined with saturable absorption in the nonlinear regime, can break Lorentz reciprocity. In this work, we introduce asymmetric losses in a pair of coupled silicon waveguides by overlaying only one of them with unbiased graphene, subject to saturable absorption. The device can be used as a broadband half-duplex isolator: a two-port component offering unidirectional transmission of high-power signals.
© The Authors, published by EDP Sciences, 2020
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