Curator's Take
This research marks a significant milestone for continuous-variable quantum computing by demonstrating the first integrated chip capable of generating two independently controllable squeezed light sources on a thin-film lithium niobate platform. The achievement is particularly noteworthy because it produces genuine quantum entanglement between the two modes while maintaining the reproducibility and tunability needed for practical quantum applications. While the 0.5 dB squeezing level is modest compared to some laboratory demonstrations, having multiple squeezed light sources on a single telecom-compatible chip represents crucial progress toward scalable photonic quantum processors that could one day perform complex quantum computations using continuous variables rather than discrete qubits.
— Mark Eatherly
Summary
Scalable generation of nonclassical light sources on an integrated platform is a key requirement for photonic quantum information processing. In particular, realizing multiple indistinguishable squeezed light sources on a single chip is an essential step toward continuous-variable quantum computing. Here, we demonstrate the fabrication of two indistinguishable and independently controllable optical parametric oscillators on a thin-film lithium niobate (TFLN) platform. The device design focuses on reproducibility, independent tunability, and compatibility with larger telecom-wavelength continuous-variable photonic circuits. We observe up to 0.5 dB of directly measured squeezing below the shot-noise level from each source. By interfering the two modes on a beam splitter, we generate an EPR-type two-mode squeezed state and verify continuous-variable entanglement through violation of the Duan-Simon inseparability criterion. This is the first demonstration of two independently tunable squeezed-light sources on a single TFLN chip and their use for generating continuous-variable entanglement.