Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Resonance of three longitudinal modes in OPO cavity and generation of two-mode squeezed-state light

Yimin Lian, Jingde Liu, Tiancai Zhang, Mauquan Huang, Kunchi Peng

Published Oct 28, 1992• 0 citations
Publisher

Abstract

Nondegenerate parametric down-conversion in OPO with two KTP crystals was experimentally researched. The two-mode squeezed state light was observed when three longitudinal modes were resonated simultaneously.
DOI
10.1117/12.130405

Related papers

Generation of two-mode squeezed states by nondegenerate optical parametric process

Kunchi Peng, Changde Xie, Maoquan Huang +4 more

The full quantum treatment on the three-mode interaction in an optical parametric oscillator (OPO) is presented. The simultaneous resonance of three nondegenerate modes in the OPO cavity has been experimentally demonstrated. Reductions in photocurrent noise of 30% relative to the vacuum noise level are obtained for frequency offsets near 2 MHz.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 11, 1993•0 citations

EXPERIMENTAL INVESTIGATION ABOUT TWO-MODE SQUEEZED STATE GENERATION OF LIGHT FIELD

Kunchi Peng, Maoquan Huang, LIU JING +6 more

Two-mode squeezed states of light field are experimentally generated by nondegenerate parametric down conversion in an optical cavity. Noise reductions of about 30% relative to the vacuum noise level are obtained in the quiet quadrature of the electromagnetic field.

Acta Physica Sinica•Jan 1, 1993•5 citations

Theoretical research on the three-mode interactions inside an OPO cavity

Tiancai Zhang, Changde Xie, Kunchi Peng

Using the linearized Langevin equations and spectral matrix, we calculated the squeezing spectra of the coupled mode in the output field for the process of parametric down-conversion with frequency degenerate but polarizations non-degenerate. The squeezing as a function of the driving field is obtained. We compare our results with that of the semiclassic and indicate that it is possible to generate a two-mode squeezed state with large amplitudes. The quantum correlation between the signal and the idler modes is also discussed.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 28, 1992•0 citations

Multimode Entangled Squeezed Light Generation and Propagation in a Coupled-Cavity Photonic Crystal

Dylan van Eeden, Marc M. Dignam

We design a photonic crystal coupled-cavity system consisting of a three-mode cavity and three waveguides to generate and deliver entangled two-mode squeezed states of light on-chip.

Photonics North (PN)•May 28, 2024•0 citations

Nonclassical effects in a mode-locked optical parametric oscillator

Robert M. Shelby, M. D. Levenson, Stephen H. Perlmutter

We have constructed a mode-locked optical parametric oscillator (OPO), synchronously pumped by the second harmonic of a continuously mode-locked Nd:YAG laser and based on type II phase matching in a KTP crystal. The two subharmonics (signal and idler waves) are nearly degenerate in frequency but are distinct orthogonal polarization states, and the oscillator is thus a nondegenerate OPO. Above threshold, the intensities of the signal and idler output beams should be highly correlated, as recently demonstrated for a similar single-frequency OPO.1 Ideally, the quantum noise on the corresponding photocurrent difference signal is completely suppressed for frequencies that are small compared to the OPO cavity bandwidth. Since this configuration produces intense light beams with potentially very good noise suppression, it is an important prototype for possible applications, e.g., to spectroscopy. Initial results with our OPO show an excess uncorrelated polarization noise, possibly due to depolarized light scattering in the KTP crystal. When the OPO cavity is stabilized with the signal and idler degenerate in frequency, they can be mixed to form a superposition by manipulating their polarization. When the oscillator is pumped below threshold, a pulsed squeezed vacuum state is produced in two such mixtures.2 When the polarizations are mixed inside the OPO cavity by a Faraday rotator, the backaction evasion necessary for a quantum nondemolition (QND) measurement of one of the field quadratures of an externally injected beam is obtained.3 The pulsed local oscillator used in observing the squeezing or QND effects is derived from the fundamental output of the pump laser. Progress in implementing these experiments with our mode-locked OPO is described as well as possible applications to time-domain measurements with noise below the shot-noise limit.

Annual Meeting Optical Society of America•Jan 1, 1988•0 citations

Phase-Sensitive Crystal-Edge Effects in Linear Optical Parametric Oscillators: Why Nominally Identical Squeezers Behave Differently

Jonas Junker, Donghwa Lee, Reda Louahaj +5 more

Efficient and reproducible squeezed-light sources are essential for quantum information processing and precision metrology. Compact linear standing-wave optical parametric oscillators (OPOs) are attractive because they combine low optical loss, low pump-power requirements, and large longitudinal mode spacing. In doubly resonant cavities, however, the nonlinear interaction is not determined solely by bulk phase matching: forward- and backward-generated fields recombine coherently, making the effective gain sensitive to crystal-edge termination, wavelength-dependent coating phases, and the cavity resonance condition. Here, we show that these microscopic phase contributions can produce large threshold variations between nominally similar OPOs. We combine double-pass second-harmonic generation with OPO threshold measurements to extract the relevant crystal-cavity phases and analyse three linear OPO systems. The observed devices exhibit threshold variations of up to nearly six-fold, traced to the phase-dependent nonlinear-gain envelope at accessible doubly resonant operating points. Our results establish a phase-aware framework for compact linear OPOs and provide design guidelines for reproducible low-threshold squeezed-light sources in scalable photonic quantum systems.

quant-pharXiv:2606.00216•Jun 2, 2026•0 citations
Using the linearized Langevin equations and spectral matrix, we calculated the squeezing spectra of the coupled mode in the output field for the process of parametric down-conversion with frequency degenerate but polarizations non-degenerate. The squeezing as a function of the driving field is obtained. We compare our results with that of the semiclassic and indicate that it is possible to generate a two-mode squeezed state with large amplitudes. The quantum correlation between the signal and the idler modes is also discussed.
We have constructed a mode-locked optical parametric oscillator (OPO), synchronously pumped by the second harmonic of a continuously mode-locked Nd:YAG laser and based on type II phase matching in a KTP crystal. The two subharmonics (signal and idler waves) are nearly degenerate in frequency but are distinct orthogonal polarization states, and the oscillator is thus a nondegenerate OPO. Above threshold, the intensities of the signal and idler output beams should be highly correlated, as recently demonstrated for a similar single-frequency OPO.1 Ideally, the quantum noise on the corresponding photocurrent difference signal is completely suppressed for frequencies that are small compared to the OPO cavity bandwidth. Since this configuration produces intense light beams with potentially very good noise suppression, it is an important prototype for possible applications, e.g., to spectroscopy. Initial results with our OPO show an excess uncorrelated polarization noise, possibly due to depolarized light scattering in the KTP crystal. When the OPO cavity is stabilized with the signal and idler degenerate in frequency, they can be mixed to form a superposition by manipulating their polarization. When the oscillator is pumped below threshold, a pulsed squeezed vacuum state is produced in two such mixtures.2 When the polarizations are mixed inside the OPO cavity by a Faraday rotator, the backaction evasion necessary for a quantum nondemolition (QND) measurement of one of the field quadratures of an externally injected beam is obtained.3 The pulsed local oscillator used in observing the squeezing or QND effects is derived from the fundamental output of the pump laser. Progress in implementing these experiments with our mode-locked OPO is described as well as possible applications to time-domain measurements with noise below the shot-noise limit.
Efficient and reproducible squeezed-light sources are essential for quantum information processing and precision metrology. Compact linear standing-wave optical parametric oscillators (OPOs) are attractive because they combine low optical loss, low pump-power requirements, and large longitudinal mode spacing. In doubly resonant cavities, however, the nonlinear interaction is not determined solely by bulk phase matching: forward- and backward-generated fields recombine coherently, making the effective gain sensitive to crystal-edge termination, wavelength-dependent coating phases, and the cavity resonance condition. Here, we show that these microscopic phase contributions can produce large threshold variations between nominally similar OPOs. We combine double-pass second-harmonic generation with OPO threshold measurements to extract the relevant crystal-cavity phases and analyse three linear OPO systems. The observed devices exhibit threshold variations of up to nearly six-fold, traced to the phase-dependent nonlinear-gain envelope at accessible doubly resonant operating points. Our results establish a phase-aware framework for compact linear OPOs and provide design guidelines for reproducible low-threshold squeezed-light sources in scalable photonic quantum systems.