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

Squeezed pulsed light from a fiber ring interferometer

K. Bergman, H. A. Haus

Published Feb 1, 1992• 1 citation
OpenAlex

Abstract

Observation of squeezed noise, 5 +/- 0.3 dB below the shot noise level, generated with pulses in a fiber ring interferometer is reported. The interferometric geometry is used to separate the pump pulse from the squeezed vacuum radiation. A portion of the pump is reused as the local oscillator in a homodyne detection. The pump fluctuations are successfully subtracted and shot noise limited performance is achieved at low frequencies (35-85 KHz). A possible utilization of the generated squeezed vacuum in improving a fiber gyro's signal to noise ratio is discussed.

Related papers

Squeezing in fibers with optical pulses

K. Bergman, H. A. Haus

A novel method of squeezing with optical pulses in a fiber ring reflector is demonstrated experimentally. Squeezing of greater than 5 +/- 0.3 dB has been observed. The pump is separated from the squeezed radiation with a fiber ring reflector and can be reused, in principle fully, as the local oscillator. The detection is at low frequencies (35-85 kHz) and is unaffected by guided-acoustic-wave Brillouin scattering.

Optics Letters•May 1, 1991•196 citations

Squeezed pulse vacuum from fiber-ring interferometer

K. Bergman, H. A. Haus

Squeezing with degenerate parametric amplification sacrifices the power needed for the pump.1 Squeezing by using the third- order nonlinearity does not necessarily sacrifice the pump power, because it remains at the same frequency as the squeezed radiation. Because the third-order nonlinearity is weak, long interaction lengths must be used, i.e., optical fibers. Past experiments with quasi excitation in optical fibers were plagued by stimulated Brillouin scattering (SBS) and guided acoustic wave acoustic Brillouin scattering (GAWBS).2 The use of pulses raises the peak power and the SBS threshold, allowing use of shorter fibers. A Mach-Zehnder interferometer configuration separates the pump from the squeezed vacuum.3 This has two advantages: the pump power can be reused as the local oscillator power, and the squeezed radiation can be measured closer to zero frequency (30 kHz) because the pump fluctuations are absent.

Annual Meeting Optical Society of America•Jan 1, 1990•0 citations

Squeezed soliton fiber gyro

K. Bergman, H. A. Haus, Yinchieh Lai +1 more

Experiments in our laboratory have arrived at squeezing in a pulse-excited fiber ring. The pulse excitation suppresses stimulated Brillouin scattering, and at the low frequencies used for the measurement, which are made possible by the pump separation, guided acoustic-wave Brillouin scattering is ineffective. It is likely that large squeezing can be realized by using solitons in the same fiber-ring configuration, because solitons assure better squeezing phase profiles. These findings encouraged us to "design" a fiber gyro that performs below the standard quantum limit. It consists of two fiber-ring reflectors; the first acts as a squeezer, and the second acts as a Sagnac interferometer. We use the theory of quantization of solitons.1 The pulse injected into the first fiber ring is a sech adjusted so as to travel as a pair of countertraveling solitons in the squeezing ring.2 The ring acts like a Mach-Zehnder interferometer folded back on itself. The pump is reflected from the pump port, and the vacuum port has squeezed vacuum emerging from it. The pump is recycled in the second Sagnac ring to act as the signal for the rotation sensing. The squeezed vacuum from the first ring is injected into the vacuum port of the Sagnac interferometer. Because practical design considerations dictate fiber lengths on the order of 100 m for both rings, the nonlinearity in the Sagnac ring cannot be neglected. It produces its own squeezing but in the wrong phase for detector noise reduction. However, by proper adjustment of the squeezing in both interferometers, it is possible to counteract the harmful squeezing effect in the Sagnac interferometer and still arrive at a net reduction of the detector noise.

Annual Meeting Optical Society of America•Jan 1, 1990•0 citations

Sub-shot-noise measurement with fiber-squeezed optical pulses

K. Bergman, Christopher Richard Doerr, H. A. Haus +1 more

A novel scheme employing two pulses separated by a short time delay is used to cancel the phase noise from guided-acoustic-wave Brillouin scattering in a fiber ring interferometer. The dual-pulse-excited fiber ring is used to generate squeezed vacuum that, when injected into a measuring Mach–Zehnder interferometer, improves its sensitivity by 3 dB beyond the shot-noise limit.

Optics Letters•Apr 15, 1993•57 citations

Generation of multi-mode squeezed vacuum using pulse pumped fiber optical parametric amplifiers

Nannan Liu, Yuhong Liu, Jiamin Li +2 more

Multimode squeezed states are essential resources in quantum information processing and quantum metrology with continuous variables. Here we present the experimental generation of squeezed vacuum via the degenerate four wave mixing realized by pumping a piece of dispersion shifted fiber with mode-locked ultrafast pulse trains. The noise fluctuation is lower than the shot noise limit by 1.1 ± 0.08 dB (1.95 ± 0.17 dB after correction for detection losses). The detailed investigation illustrates that the results can be further improved by suppressing Raman scattering and by reshaping the spectrum of the local oscillator to achieve the required mode-matching of the homodyne detection system. Our study is useful for developing a compact fiber source of multi-mode squeezed vacuum.

Optics Express•Jan 27, 2016•11 citations

Squeezed light for the interferometric detection of high-frequency gravitational waves

Roman Schnabel, J. Harms, K. A. Strain +1 more

The quantum noise of the light field is a fundamental noise source in interferometric gravitational wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called Standard-Quantum-Limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyze the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO600 detector with present design parameters will benefit from frequency dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO600 will still be dominated by shot-noise and improved by a factor of 10^{6dB/20dB}~2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6x10^{-23} above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency dependent squeezing by introducing an additional optical component to GEO600s signal-recycling cavity.

arXiv:gr-qc/0401119•Classical and Quantum Gravity•Feb 12, 2004•26 citations
Observation of squeezed noise, 5 +/- 0.3 dB below the shot noise level, generated with pulses in a fiber ring interferometer is reported. The interferometric geometry is used to separate the pump pulse from the squeezed vacuum radiation. A portion of the pump is reused as the local oscillator in a homodyne detection. The pump fluctuations are successfully subtracted and shot noise limited performance is achieved at low frequencies (35-85 KHz). A possible utilization of the generated squeezed vacuum in improving a fiber gyro's signal to noise ratio is discussed.
Squeezing with degenerate parametric amplification sacrifices the power needed for the pump.1 Squeezing by using the third- order nonlinearity does not necessarily sacrifice the pump power, because it remains at the same frequency as the squeezed radiation. Because the third-order nonlinearity is weak, long interaction lengths must be used, i.e., optical fibers. Past experiments with quasi excitation in optical fibers were plagued by stimulated Brillouin scattering (SBS) and guided acoustic wave acoustic Brillouin scattering (GAWBS).2 The use of pulses raises the peak power and the SBS threshold, allowing use of shorter fibers. A Mach-Zehnder interferometer configuration separates the pump from the squeezed vacuum.3 This has two advantages: the pump power can be reused as the local oscillator power, and the squeezed radiation can be measured closer to zero frequency (30 kHz) because the pump fluctuations are absent.
Experiments in our laboratory have arrived at squeezing in a pulse-excited fiber ring. The pulse excitation suppresses stimulated Brillouin scattering, and at the low frequencies used for the measurement, which are made possible by the pump separation, guided acoustic-wave Brillouin scattering is ineffective. It is likely that large squeezing can be realized by using solitons in the same fiber-ring configuration, because solitons assure better squeezing phase profiles. These findings encouraged us to "design" a fiber gyro that performs below the standard quantum limit. It consists of two fiber-ring reflectors; the first acts as a squeezer, and the second acts as a Sagnac interferometer. We use the theory of quantization of solitons.1 The pulse injected into the first fiber ring is a sech adjusted so as to travel as a pair of countertraveling solitons in the squeezing ring.2 The ring acts like a Mach-Zehnder interferometer folded back on itself. The pump is reflected from the pump port, and the vacuum port has squeezed vacuum emerging from it. The pump is recycled in the second Sagnac ring to act as the signal for the rotation sensing. The squeezed vacuum from the first ring is injected into the vacuum port of the Sagnac interferometer. Because practical design considerations dictate fiber lengths on the order of 100 m for both rings, the nonlinearity in the Sagnac ring cannot be neglected. It produces its own squeezing but in the wrong phase for detector noise reduction. However, by proper adjustment of the squeezing in both interferometers, it is possible to counteract the harmful squeezing effect in the Sagnac interferometer and still arrive at a net reduction of the detector noise.
Multimode squeezed states are essential resources in quantum information processing and quantum metrology with continuous variables. Here we present the experimental generation of squeezed vacuum via the degenerate four wave mixing realized by pumping a piece of dispersion shifted fiber with mode-locked ultrafast pulse trains. The noise fluctuation is lower than the shot noise limit by 1.1 ± 0.08 dB (1.95 ± 0.17 dB after correction for detection losses). The detailed investigation illustrates that the results can be further improved by suppressing Raman scattering and by reshaping the spectrum of the local oscillator to achieve the required mode-matching of the homodyne detection system. Our study is useful for developing a compact fiber source of multi-mode squeezed vacuum.
The quantum noise of the light field is a fundamental noise source in interferometric gravitational wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called Standard-Quantum-Limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyze the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO600 detector with present design parameters will benefit from frequency dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO600 will still be dominated by shot-noise and improved by a factor of 10^{6dB/20dB}~2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6x10^{-23} above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency dependent squeezing by introducing an additional optical component to GEO600s signal-recycling cavity.