lithium niobate / 06 Devices / 6.7
6.7 Quantum devices: squeezers, pair sources, converters, transducers
L1 Phenomenon
Quantum light needs low loss and strong nonlinearity on the same chip. TFLN waveguides squeeze the noise of light below the vacuum level, make entangled photon pairs, and convert single photons between colors. With a superconducting circuit nearby, the Pockels effect or a sound wave can turn microwave photons from a quantum processor into optical photons for fiber.
Microwave-optical transduction efficiency, LN devices9 values, 8 devices
○ cavity EO□ piezo-optomechanical◇ bulk LN EO (not thin film)filled: cryogenic; hollow: room temperature or not statedline: same device, total and internal
Values as reported (transducer table above) reported; definitions differ (total, internal, on chip; most abstracts do not name one) and added noise is not shown. Year: Crossref issued year.
ring: cavity EObeam with holes: piezo-optomechanicaldisk: bulk LN whispering galleryfilled: cryogenic, hollow: room temperature or not stated
Hiding internal and on-chip values leaves the end-to-end numbers. Values as reported (transducer table above) reported; definitions differ (total, internal, on chip; most abstracts do not name one) and added noise is not shown. Dashed line: same device, total and internal. Year: Crossref issued year.
L2 Squeezing, pairs, conversion, transducers
Squeezing, pairs, conversion
| Device | Value | Source |
|---|---|---|
| On-chip squeezing, TFLN | 4.9 dB measured, > 25 THz | reported |
| Single-pass squeezing | 0.56 dB measured | reported |
| OPO squeezing, on-chip SHG pump | 0.55 dB squeezing, 1.55 dB anti-squeezing | reported |
| Bulk-bonded PPLN ridge (not TFLN), comparison | 8.3 dB, CW | reported |
| Pair source, PPLN waveguide | CAR > 67,000; heralded g(2)(0) < 0.025 | reported |
| Pair source, PPLN microring | 36.3 MHz pair rate at 13.4 µW; CAR up to 14,682; g(2)(0) = 0.008 | reported |
| Quantum frequency conversion, telecom to near-visible | 73% internal, 900 counts/s noise | reported |
Microwave-optical transducers
| Device | Efficiency | Conditions | Source |
|---|---|---|---|
| TFLN cavity EO | 2.7×10−5 | reported | |
| Triply resonant LN on sapphire | 6.6×10−6 on chip | cryogenic | reported |
| TFLN + superconducting resonator, EO | 1.02% total (15.2% internal), bidirectional | cryogenic | reported |
| Piezo-optomechanical, room temperature | 5.5% with 323 µW blue-detuned pump; acousto-optic Vπ 0.02 V | room temperature | reported |
| Optically heralded microwave photon addition | 5% CW conversion; 15 Hz heralding | cryogenic | reported |
| Integrated interface, LN-on-Si mechanics | 0.9% at 1 µW; 14.8 MHz bandwidth | cryogenic | reported |
| Optical control of a superconducting qubit, TFLN EO | up to 1.18% | cryogenic | reported |
| Bulk LN whispering-gallery EO (not thin film) | 8.7% at 0.16 added noise photons | cryogenic | reported |
Air-clad TFLN raised the sustainable intracavity pump power at cryogenic temperature by suppressing the photorefractive effect reported.
L3 Definitions
- Squeezing: measured vs inferred (loss-corrected) values differ by several dB; only measured values are tabulated.
- Transducer efficiency definitions differ (total, internal, on-chip, photon-number); added noise matters as much as efficiency; cryogenic and room-temperature devices are marked separately.
Sources
| Ref | Title | Link |
|---|---|---|
| Chen et al. 2022 | Ultra-broadband quadrature squeezing with thin-film lithium niobate nanophotonics | doi:10.1364/OL.447695 |
| Holzgrafe et al. 2020 | Cavity electro-optics in thin-film lithium niobate for efficient microwave-to-optical transduction | doi:10.1364/OPTICA.397513 |
| Jiang et al. 2020 | Efficient bidirectional piezo-optomechanical transduction between microwave and optical frequency | doi:10.1038/s41467-020-14863-3 |
| Jiang et al. 2023 | Optically heralded microwave photon addition | doi:10.1038/s41567-023-02129-w |
| Kashiwazaki et al. 2023 | Over-8-dB squeezed light generation by a broadband waveguide optical parametric amplifier toward fault-tolerant ultra-fast quantum computers | doi:10.1063/5.0144385 |
| Ma et al. 2020 | Ultrabright Quantum Photon Sources on Chip | doi:10.1103/PhysRevLett.125.263602 |
| McKenna et al. 2020 | Cryogenic microwave-to-optical conversion using a triply resonant lithium-niobate-on-sapphire transducer | doi:10.1364/OPTICA.397235 |
| Nehra et al. 2022 | Few-cycle vacuum squeezing in nanophotonics | doi:10.1126/science.abo6213 |
| Park et al. 2024 | Single-mode squeezed-light generation and tomography with an integrated optical parametric oscillator | doi:10.1126/sciadv.adl1814 |
| Sahu et al. 2022 | Quantum-enabled operation of a microwave-optical interface | doi:10.1038/s41467-022-28924-2 |
| Wang et al. 2023 | Quantum frequency conversion and single-photon detection with lithium niobate nanophotonic chips | doi:10.1038/s41534-023-00704-w |
| Warner et al. 2025 | Coherent control of a superconducting qubit using light | doi:10.1038/s41567-025-02812-0 |
| Weaver et al. 2023 | An integrated microwave-to-optics interface for scalable quantum computing | doi:10.1038/s41565-023-01515-y |
| Xu et al. 2021 | Bidirectional interconversion of microwave and light with thin-film lithium niobate | doi:10.1038/s41467-021-24809-y |
| Zhao et al. 2020 | High Quality Entangled Photon Pair Generation in Periodically Poled Thin-Film Lithium Niobate Waveguides | doi:10.1103/PhysRevLett.124.163603 |