Nanophotonic source of quadrature squeezing via self-phase modulation

Squeezed light is optical beams with variance below the shot noise level. They are a key resource for quantum technologies based on photons, and they can be used to achieve better precision measurements and improve security in quantum key distribution channels and as a fundamental resource for quantum computation. Here, we demonstrate an integrated source of squeezing based on four-wave mixing that requires a single laser pump, measuring 0.45 dB of broadband quadrature squeezing at high frequencies. We identify and verify that the current results are limited by excess noise produced in the chip and propose ways to reduce it. Calculations suggest that an improvement in the optical properties of the chip achievable with existing technology can develop scalable quantum technologies based on light.