Physics

Coherent states

Nonlinear system

Squeezed coherent state

Resonator

Noise (video)

Image (mathematics)

Optics

Artificial intelligence

Photonics

Nanophotonics

Computer science

Quantum mechanics

Degenerate energy levels

Optoelectronics

Broadband

Quantum optics

Quantum

Nature Communications

Delicate engineering of integrated nonlinear structures is required for developing scalable sources of non-classical light to be deployed in quantum information processing systems. In this work, we demonstrate a photonic molecule composed of two coupled microring resonators on an integrated nanophotonic chip, designed to generate strongly squeezed light uncontaminated by noise from unwanted parasitic nonlinear processes. By tuning the photonic molecule to selectively couple and thus hybridize only the modes involved in the unwanted processes, suppression of parasitic parametric fluorescence is accomplished. This strategy enables the use of microring resonators for the efficient generation of degenerate squeezed light: without it, simple single-resonator structures cannot avoid contamination from nonlinear noise without significantly compromising pump power efficiency. We use this device to generate 8(1) dB of broadband degenerate squeezed light on-chip, with 1.65(1) dB directly measured.

Squeezed light from a nanophotonic molecule