Thin-film Lithium Niobate for Integrated Quantum Optics

Abstract

The generation of broadband squeezed light is a vital resource within continuous-variable quantum information processing. In light-based quantum computation protocols, the amount of squeezing impacts computation error rates, therefore achieving fault-tolerant quantum computation requires a sufficiently high level of squeezing. Traditionally, squeezed light has been generated using bulk nonlinear crystals located within optical cavities, however this comes at the cost of a narrow squeezing bandwidth which reduces operational speed. Recently, the thin-film Lithium Niobate has emerged as a promising material platform for the generation of broadband squeezed light, however current demonstrations have been limited. In this work using periodically polled nanophotonic waveguides in thin-film Lithium Niobate, we study the generation and manipulation of broadband squeezed light. In utilising the high peak powers offered by ultrashort pulses we demonstrate for the first time, the generation of broadband squeezed light in a Silicon-Nitride strip loaded thin-film Lithium Niobate waveguide at telecommunication wavelengths. Furthermore, we theoretically investigate the performance of an integrated coherent feedback squeezer, a device which enables coherent control over the level of squeezing. These results contribute to the realisation of a fault-tolerant photonic quantum computer and development of continuous-variable quantum information processing.