Optimizing for a Near Single-Mode Type-0 Optical Parametric Amplifier in Nanophotonics

TL;DR

This paper presents the design and numerical demonstration of a highly spectrally pure, single-mode type-0 optical parametric amplifier in thin-film lithium niobate nanophotonics, enabling advanced quantum and ultrafast applications.

Contribution

It introduces optimized waveguide parameters for achieving high spectral purity in type-0 OPAs within TFLN, a novel achievement in integrated nonlinear photonics.

Findings

Spectral purity of 0.982 achieved in simulations.

Demonstrated potential for ultra-fast quantum random number generation.

Optimized waveguide design parameters for single-mode operation.

Abstract

Thin-film lithium niobate (TFLN) has recently emerged as a promising platform for integrated nonlinear photonics, enabling the use of optical parametric amplifiers (OPAs) for applications in quantum information processing, precision metrology, and ultrafast optical signal processing. However, OPA waveguide designs have not yet achieved the phase-matching conditions for type-0 operation in a single spectro-temporal mode, limiting their use. We optimize the waveguide dimensions, poling pattern, pump wavelength, and pump pulse duration for high spectral purity, a metric for single-mode fidelity. We numerically demonstrate a nanophotonic OPA with a spectral purity of 0.982 in a TFLN waveguide. Through semi-classical simulations, we further demonstrate that in the optical parametric regime, where vacuum fluctuations at the input of the OPA can saturate the gain and deplete the pump, the macroscopic output of such a single-mode OPA can be utilized for an ultra-fast quantum random number generator. These results demonstrate a promising direction for integrated OPAs in a wide range of ultrafast quantum nanophotonics applications.