Speaker
Description
Squeezed states of light are an established resource for continuous variable quantum enhanced precision measurements, with frequency nondegenerate (two mode) squeezed states being particularly relevant for quantum communication and sensing [1]. These states are conventionally generated using optical cavity based optical parametric oscillators, where the entangled sideband pairs are generated between upper and lower cavity free-spectral ranges (FSRs). This approach results in limited spectral coverage as the entangled sidebands are restrticted to the cavity linewidth and subject to intracavity loss. Conventionally, the readout of these systems has required balanced homodyne detection of the individual modes.
In our approach here, we generate broadband squeezed vacuum via spontaneous parametric downconversion in a fibre coupled lithium niobate waveguide, a platform previously shown to support continuous wave squeezing beyond 10 dB over terahertz bandwidths. This absolves the restrictions imposed by the FSR in cavity implementations [3]. Within the phase matching bandwidth, any sideband pair symmetric about the degeneracy frequency and satisfying $\omega_p=\omega_+ + \omega_-$ is Einstein-Podolsky-Rosen (EPR) entangled [2]. We can select the two mode squeezed state at $\omega_0 \pm \Delta$, using a dual-quadrature demodulation, unrestricted by a cavity mode structure. By tuning the demodulation phase relative to the optical local oscillator phase, the EPR joint quadratures can be recovered [4,5], equivalent to balanced heterodyne detection [6].
This talk outlines an all-fiber waveguide source and alternative readouts. We will report on efforts to identify the limiting efficiency budget, and distributed squeezed light transfer.
[1] R.N.Clark et al. Nat. Photon. 20, 489–503 (2026).
[2] Y.Ma et al. Nat. Phys. \textbf{13}, 776 (2017).
[3] G.Ha, et al, arXiv:2603.02744 [quant-ph]
[4] B.Xie et al, J. Opt. Soc. Am. B \textbf{35}, 2342 (2018).
[5] H.Song et al. Phys. Rev. A \textbf{90}, 042337 (2014).
[6] D.W. Gould et al. Phys. Rev. Lett. \textbf{133}, 063602 (2024).
| I am the presenting author | Yes |
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