Diana A. Antonosyan

Parity-time anti-symmetric parametric amplifier.

We predict that directional coupler of quadratically nonlinear and lossy waveguides can perform ultrafast signal switching and parametric amplification, using the pump-controlled breaking of the parity-time anti-symmetry associated with nonlinear wave mixing.

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

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 Schrodinger-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 non-classical spatial correlations.

Optical emulation of photon-pair generation in nonlinear lossy waveguides

We establish theoretically and demonstrate experimentally that photon-pair generation through spontaneous parametric down-conversion in a nonlinear waveguide with scattering or material losses can be effectively emulated by classical laser light propagation through a specially designed linear waveguide circuit. This platform can represent arbitrary photon and pump losses, with a potential for the emulation of non-Markovian decay. We characterize the photon-pair correlation spectrum and observe its characteristic transformation from the well-known sinc-shape in lossless waveguides towards a Lorentzian shape in the presence of photon loss.

Parity-time anti-symmetric parametric amplification

We describe the process of parametric amplification in a directional coupler of quadratically nonlinear and lossy waveguides, which belong to a class of optical systems with spatial parity-time (PT) symmetry in the linear regime. We identify a distinct spectral parity-time anti-symmetry associated with optical parametric interactions, and show that pump-controlled symmetry breaking can facilitate spectrally selective mode amplification in analogy with PT lasers. We also establish a connection between breaking of spectral and spatial mode symmetries, revealing the potential to implement unconventional regimes of spatial light switching through ultrafast control of PT breaking by pump pulses.

Parity-Time Anti-Symmetric Parametric Amplifier with Ultrafast All-Optical Switching

We predict that directional coupler of nonlinear and lossy waveguides can perform ultrafast signal switching and parametric amplification, using the pump-controlled breaking of the parity-time anti-symmetry associated with nonlinear wave mixing.

Loss-tolerant photon-pair generation and quantum walks in nonlinear waveguide arrays

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.