Effect of loss on photon-pair generation and correlations in nonlinear waveguide arrays

Diana A. Antonosyan, Alexander S. Solntsev, Andrey A. Sukhorukov

We describe theoretically the process of spontaneous parametric down-conversion in quadratic nonlinear waveguide arrays in the presence of linear loss. We derive a set of discrete Schr\"odinger-type equations for the biphoton wave function and the wave function of one photon when the other photon in a pair is lost. We demonstrate effects arising from loss-affected interference between the generated photon pairs and show that nonlinear waveguide arrays can serve as a robust loss-tolerant integrated platform for the generation of entangled photon states with nonclassical spatial correlations.

M. Bertolotti, M. Angelis, Concita Sibilia +1 more

F. Baboux

Diana A. Antonosyan, Alexander S. Solntsev, Andrey A. Sukhorukov +1 more

We demonstrate that generation and quantum walks of biphotons with non-classical spatial correlations in nonlinear waveguide arrays is tolerant to losses for different pump regimes, and suggest quick loss characterization approach based on nonlinear spectroscopy.

Alexander S. Solntsev, Andrey A. Sukhorukov, Dragomir N. Neshev +1 more

Arrays of coupled optical waveguides provide a flexible platform for manipulation of optical beams and pulses. Recently, the propagation of non-classical light in waveguide arrays has shown a surging attention. It was shown that quantum walks of correlated photon pairs realized through propagation in waveguide arrays can lead to nontrivial quantum correlations at the array output. However, all currently used schemes for quantum walks utilise correlated photon pairs generated externally to the array. Here, we propose and demonstrate numerically a novel scheme enabling simultaneous generation of correlated photon pair through spontaneous parametric downconversion (SPDC) and quantum walks inside a single photonic element an array of quadratic nonlinear waveguides. This scheme avoids entirely the need for complex interfaces between the different photonic elements and enables novel ways for control of the quantum correlations.

Stephen R. Friberg