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

Quantum noise limits of a semiconductor laser with dispersive optical feedback

Yaakov Shevy, Hua Deng, S. Mahnkopf, John E. Kitching, Amnon Yariv

Published May 24, 1999• 0 citations
Publisher

Abstract

The quantum noise limits of a semiconductor laser with dispersive loss are examined theoretically and experimentally. Using optical feedback from Cs vapor as a dispersive loss element we demonstrate almost 6 orders of magnitude reduction in the linewidth, to a 44 Hz level, and 1.9 dB amplitude noise squeezing below the standard quantum noise limit.

DOI
10.1117/12.349261

Related papers

Quantum noise reduction in semiconductor lasers using dispersive optical feedback

John Edward Kitching

This thesis describes the phase and amplitude noise properties of semiconductor lasers subjected to weak, dispersive optical feedback. In the first half, experiments demonstrating reductions in the laser frequency noise power spectrum and spectral linewidth by several orders of magnitude are presented. Weak optical feedback is applied to the laser by an external cavity containing an atomic vapor. The presence of the vapor adds to the dispersion of the cavity and simultaneously locks the laser to a fixed frequency reference. The role of 1/f frequency noise in limiting the effectiveness of this linewidth reduction technique is investigated and 1/f noise is found to be the dominant contribution to the linewidth under strong optical feedback conditions. An electronic feedback scheme utilizing FM sideband locking is then implemented alongside the optical feedback, and an additional reduction in the low frequency 1/f frequency noise power spectrum by over two orders of magnitude is obtained. With both systems operating simultaneously, the spectral linewidth is narrowed from its free-running value of about 20 MHz to 1.4 kHz. Excellent absolute frequency stability is also achieved. In the second half, the effects of optical feedback on the quantum mechanical amplitude noise properties of the laser are examined. A fully quantum mechanical theory of amplitude and phase noise for a semiconductor laser with weak optical feedback is developed, and the nature and limits of the noise reduction using this technique are established. Particular attention is given to the feedback-induced enhancement of the amplitude squeezing which can be obtained in a pump-suppressed semiconductor laser: an improvement in the squeezing by 3 dB is predicted under moderate pumping. Somewhat larger noise reductions are expected when the laser is operating closer to threshold. Measurements performed on a laser biased close to threshold are then described and a reduction in the low frequency amplitude noise power spectrum by 7 dB is obtained. An experimental investigation of the effects of optical feedback on the amplitude squeezing in a semiconductor laser is then discussed. The low frequency squeezing in a room temperature device is increased from 3% below the standard quantum limit (SQL) under free-running conditions to 19% below the SQL with optimal feedback. The experimental results are found to agree poorly with the single-mode model and a multi-mode model including the effects of asymmetrical cross-mode non-linear gain is developed to explain the discrepancy. Finally, further experimental investigation into the generation of amplitude squeezed light is presented using a commercial laser with no intentional external modifications. Squeezing as large as 29% below the SQL is measured using a balanced homodyne detector with the laser operating near room temperature, corresponding to 41% below the SQL at the output facet of the laser.

•Jan 1, 1995•1 citation

Amplitude noise reduction in semiconductor lasers with weak, dispersive optical feedback

John E. Kitching, Yaakov Shevy, Robert W. Boyd +1 more

We present the theory and measurements of the amplitude noise spectrum from a semiconductor laser with weak optical feedback (P(fb)/P(out) approximately 10(-6)) from an external cavity containing an element of dispersive loss. The laser noise is found to be reduced over most of the low-frequency spectrum, although an increase in the noise is observed at frequencies corresponding to multiples of the external-cavity free spectral range. The low-frequency noise reduction closely follows theoretical predictions, and a reduction of as much as 7 dB is measured at an injection current of 1.5 times the threshold current. The potential of this method for contributing to the production of amplitude-squeezed light is discussed.

Optics Letters•Sep 1, 1994•30 citations

Quantum amplitude modulation noise of semiconductor lasers with weak optical feedback

Hua Deng, Yaakov Shevy

We study the impact of weak dispersive optical feedback on the intensity noise of semiconductor lasers by using two-mode quantum Langevin equations with nonlinear gain and loss. The nonlinear gain arises due to spectral hole-burning and population pulsation and the nonlinear loss arises from saturable absorption by deep trap levels. We find that both the total noise and the main mode noise can be reduced with weak dispersive optical feedback; for moderate side mode suppression ratio, the main mode noise can be reduced by as much as 10 dB. Furthermore, the AM noise spectrum is found to be sensitive to the feedback phase.

Journal of Optics B Quantum and Semiclassical Optics•Mar 26, 2004•1 citation

Semiconductor laser with dispersive loss : Quantum noises and amplitude squeezing

Rashit F. Nabiev, Yuri M. Popov, Amnon Yariv

We carried out the quantum mechanical treatment of the amplitude and phase noise characteristics of internal and output light of semiconductor laser with dispersive loss inside the resonator and found the quantum limits for the noise power spectra and compared with the characteristics of the semiconductor laser without dispersive loss. In the case of noise suppressed pumping it is possible to get considerably deeper squeezing in the semiconductor laser with dispersive loss than in the laser without dispersive loss.

Journal de Physique III•Sep 1, 1992•2 citations

Use of quantum correlation for intensity noise reduction in semiconductor lasers

Anders Karlsson, Gunnar G. Bjork

The quantum correlation between junction voltage fluctuations1/frequency fluctuations2 and the intensity fluctuations of a semiconductor laser may be used to reduce the intensity noise. Here we address squeezed-state generation discussing both fundamental and practical limitations on noise reduction in conventional semiconductor lasers and microcavity lasers. In conventional semiconductor lasers, starting with intensity noise at the standard quantum limit, ideally a 3-dB amplitude squeezing is possible. This fundamental limit is set by spontaneous emission noise. Another fundamental limit is that noise reduction beyond the level set by optical losses and pump noise is not possible. It is also shown that the number-phase uncertainty in some conditions can reach the ultimate limit set by Heisenberg’s uncertainty principle. These conditions are clarified and a comparison made between junction voltage and frequency noise feedforward. Feedforward schemes realizing intensity noise reduction are discussed.

Annual Meeting Optical Society of America•Jan 1, 1991•0 citations

Generation of amplitude-squeezed light from a pump-suppressed semiconductor laser with dispersive optical feedback

John E. Kitching, Amnon Yariv, Yaakov Shevy

Amplitude-squeezed states are generated from a room-temperature semiconductor laser using a combination of pump suppression and dispersive optical feedback. The laser amplitude noise is found to be sensitive to extremely weak feedback levels, of the order of 10-8 of the output power. a reduction of the noise from 2% below the standard quantum limit (SQL) under free-running conditions to 19% below the SQL under optimal feedback conditions is obtained. A single mode theory is presented but is found to be inadequate in explaining the measured dependence of the noise reduction on the feedback power. A multimode theory including asymmetrical cross-mode nonlinear gain is proposed to explain this discrepancy.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 26, 1995•2 citations
The quantum noise limits of a semiconductor laser with dispersive loss are examined theoretically and experimentally. Using optical feedback from Cs vapor as a dispersive loss element we demonstrate almost 6 orders of magnitude reduction in the linewidth, to a 44 Hz level, and 1.9 dB amplitude noise squeezing below the standard quantum noise limit.
This thesis describes the phase and amplitude noise properties of semiconductor lasers subjected to weak, dispersive optical feedback. In the first half, experiments demonstrating reductions in the laser frequency noise power spectrum and spectral linewidth by several orders of magnitude are presented. Weak optical feedback is applied to the laser by an external cavity containing an atomic vapor. The presence of the vapor adds to the dispersion of the cavity and simultaneously locks the laser to a fixed frequency reference. The role of 1/f frequency noise in limiting the effectiveness of this linewidth reduction technique is investigated and 1/f noise is found to be the dominant contribution to the linewidth under strong optical feedback conditions. An electronic feedback scheme utilizing FM sideband locking is then implemented alongside the optical feedback, and an additional reduction in the low frequency 1/f frequency noise power spectrum by over two orders of magnitude is obtained. With both systems operating simultaneously, the spectral linewidth is narrowed from its free-running value of about 20 MHz to 1.4 kHz. Excellent absolute frequency stability is also achieved. In the second half, the effects of optical feedback on the quantum mechanical amplitude noise properties of the laser are examined. A fully quantum mechanical theory of amplitude and phase noise for a semiconductor laser with weak optical feedback is developed, and the nature and limits of the noise reduction using this technique are established. Particular attention is given to the feedback-induced enhancement of the amplitude squeezing which can be obtained in a pump-suppressed semiconductor laser: an improvement in the squeezing by 3 dB is predicted under moderate pumping. Somewhat larger noise reductions are expected when the laser is operating closer to threshold. Measurements performed on a laser biased close to threshold are then described and a reduction in the low frequency amplitude noise power spectrum by 7 dB is obtained. An experimental investigation of the effects of optical feedback on the amplitude squeezing in a semiconductor laser is then discussed. The low frequency squeezing in a room temperature device is increased from 3% below the standard quantum limit (SQL) under free-running conditions to 19% below the SQL with optimal feedback. The experimental results are found to agree poorly with the single-mode model and a multi-mode model including the effects of asymmetrical cross-mode non-linear gain is developed to explain the discrepancy. Finally, further experimental investigation into the generation of amplitude squeezed light is presented using a commercial laser with no intentional external modifications. Squeezing as large as 29% below the SQL is measured using a balanced homodyne detector with the laser operating near room temperature, corresponding to 41% below the SQL at the output facet of the laser.
We present the theory and measurements of the amplitude noise spectrum from a semiconductor laser with weak optical feedback (P(fb)/P(out) approximately 10(-6)) from an external cavity containing an element of dispersive loss. The laser noise is found to be reduced over most of the low-frequency spectrum, although an increase in the noise is observed at frequencies corresponding to multiples of the external-cavity free spectral range. The low-frequency noise reduction closely follows theoretical predictions, and a reduction of as much as 7 dB is measured at an injection current of 1.5 times the threshold current. The potential of this method for contributing to the production of amplitude-squeezed light is discussed.
We study the impact of weak dispersive optical feedback on the intensity noise of semiconductor lasers by using two-mode quantum Langevin equations with nonlinear gain and loss. The nonlinear gain arises due to spectral hole-burning and population pulsation and the nonlinear loss arises from saturable absorption by deep trap levels. We find that both the total noise and the main mode noise can be reduced with weak dispersive optical feedback; for moderate side mode suppression ratio, the main mode noise can be reduced by as much as 10 dB. Furthermore, the AM noise spectrum is found to be sensitive to the feedback phase.
We carried out the quantum mechanical treatment of the amplitude and phase noise characteristics of internal and output light of semiconductor laser with dispersive loss inside the resonator and found the quantum limits for the noise power spectra and compared with the characteristics of the semiconductor laser without dispersive loss. In the case of noise suppressed pumping it is possible to get considerably deeper squeezing in the semiconductor laser with dispersive loss than in the laser without dispersive loss.
The quantum correlation between junction voltage fluctuations1/frequency fluctuations2 and the intensity fluctuations of a semiconductor laser may be used to reduce the intensity noise. Here we address squeezed-state generation discussing both fundamental and practical limitations on noise reduction in conventional semiconductor lasers and microcavity lasers. In conventional semiconductor lasers, starting with intensity noise at the standard quantum limit, ideally a 3-dB amplitude squeezing is possible. This fundamental limit is set by spontaneous emission noise. Another fundamental limit is that noise reduction beyond the level set by optical losses and pump noise is not possible. It is also shown that the number-phase uncertainty in some conditions can reach the ultimate limit set by Heisenberg’s uncertainty principle. These conditions are clarified and a comparison made between junction voltage and frequency noise feedforward. Feedforward schemes realizing intensity noise reduction are discussed.
Amplitude-squeezed states are generated from a room-temperature semiconductor laser using a combination of pump suppression and dispersive optical feedback. The laser amplitude noise is found to be sensitive to extremely weak feedback levels, of the order of 10-8 of the output power. a reduction of the noise from 2% below the standard quantum limit (SQL) under free-running conditions to 19% below the SQL under optimal feedback conditions is obtained. A single mode theory is presented but is found to be inadequate in explaining the measured dependence of the noise reduction on the feedback power. A multimode theory including asymmetrical cross-mode nonlinear gain is proposed to explain this discrepancy.