© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Journal of Modern Optics

Sub-poissonian Light and Photocurrent Shot-noise Suppression in Closed Optoelectronic Loop

Anatoly Viktorovich Masalov, A. A. Putilin, Michael Vasilyev

Published Oct 1, 1994• 23 citations

Abstract

Photocurrent shot-noise suppression is observed in closed optoelectronic loop below the limit (1 − η) of standard shot-noise level (SNL) imposed by conventional theory of photodetector with quantum efficiency η. Experimental results on photocurrent noise are presented for different values of feedback strength and quantum efficiency η of in-loop photodiode. It is shown that at fixed feedback strength the suppression factor does not depend on η. Minimum noise spectral density is observed below the SNL by a factor 17·8 (− 12·5 dB). Such large suppression cannot be explained in terms of an ordinary sub-Poissonian light state in the loop. We suggest the concept of an anticorrelation light state, where the light in the loop is described as a non-stationary state with Poissonian quantum fluctuations, and superimposed anticorrelated classical fluctuations. While the degree of noise reduction in the photocurrent can be arbitrary large, the degree of anticorrelation between the classical and quantum fluctuations in the light beam remains limited by the quantum efficiency of the feedback photodiode. Calculations based on this concept are in a good agreement with experimental data on super-shot-noise power, obtained for the beam extracted from the loop by a beam splitter.

DOI: 10.1080/09500349414551841

Related papers

Intensity feedback effects on quantum-limited noise

Matthew S. Taubman, Howard M. Wiseman, David E. McClelland +1 more

We examine the quantum-limited behavior of an electro-optical intensity feedback loop and present a simple theory and experimental data showing excellent agreement. We show that, although the light incident upon the in-loop detector may be sub-Poissonian, this light has unique properties different from those of a freely propagating beam of intensity squeezed light. We support this by presenting the results of homodyne measurements of the phase noise of light extracted from the loop. The utility of the in-loop field is discussed, and it is shown that in all cases in which linear optical components are used, no advantage in signal-to-noise ratio is gained by taking measurements by using this light rather than a coherent source. We also discuss effects seen in the extracted or out-of-loop light. We demonstrate the existence of, and derive an expression for, an optimum gain for suppressing low-level classical noise. Conversely, in the high-gain limit, we demonstrate that the extra noise seen in the out-of-loop photocurrent that is due to the feedback process is expressible purely in terms of the mean photocurrents involved. Lastly, we introduce the novel concept of using an intensity feedback loop in conjunction with a squeezed source and show that the feedback loop has the capability of electronically transferring squeezing from one light beam to another.

Journal of the Optical Society of America B•Oct 1, 1995•56 citations

Generation of Sub-Poissonian Light in an Open-Loop LED System by the Quantum Correlation

Jianping Yin, Yuzhu Wang

This paper describes the generation and observation of sub-Poissonian light in an open-loop system with low quantum efficiency at room temperature. The experimental results show that the photocurrent fluctuation spectrum density can be reduced below the shot noise limit by 72% (-5.5 dB) in an open-loop light-emitting diode (LED) system at the frequency of 2 MHz. The noise reduction is not limited by quantum efficiency of the LED, or the current transfer efficiency.

Chinese Physics Letters•Dec 1, 1993•2 citations

Suppression of closed-loop photocurrent fluctuation below amplifier dark noise

Jianping Yin, Weijian Gao, Yifu Zhu +1 more

Suppression of the closed-loop photocurrent fluctuation below the amplifier dark noise was observed in both a negative-feedback light-emitting diode and a laser diode. We apply the concept of an anticorrelation light state proposed by Masalov et al to analyze the anticorrelation effect between the measured photocurrent fluctuation and the amplifier dark noise, which successfully explains our experimental observations. Our theoretical analysis also yields the squeezed spectrum of the light intensity fluctuation in the loop and the correlation coefficient between the photocurrent and the amplifier noise.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jul 19, 1999•0 citations

Sub-Poissonian processes in quantum optics

L. Davidovich

The author reviews methods for generating sub-Poissonian light and related concepts. This light has energy fluctuations reduced below the level which corresponds to a classical Poissonian process (shot-noise level). After an introduction to the concept of nonclassical light, an overview is given of the main methods of quantum-noise reduction. Sub-Poissonian processes are exemplified in different areas of optics, ranging from single-atom resonance fluorescence to nonlinear optics, laser physics, and cavity quantum electrodynamics. Emphasis is placed on the conceptual foundations, and on developments in laser theory that lead to the possibility, already demonstrated experimentally, of linewidth narrowing and sub-Poissonian light generation in lasers and masers. The sources of quantum noise in these devices are analyzed, and four noise-suppression methods are discussed in detail: regularization of the pumping, suppression of spontaneous-emission noise, nonadiabatic evolution of the atomic variables, and twin-beam generation.

Reviews of Modern Physics•Jan 1, 1996•358 citations

Feedback-measurement–induced anticorrelation between in-loop photocurrent fluctuation and amplifier dark noise

Jianping Yin, Weijian Gao, Yuzhu Wang +2 more

Suppression of in-loop photocurrent fluctuation below the amplifier dark noise was observed in both a negative-feedback light-emitting diode (LED) and a laser diode (LD). We use a new semiclassical model to analyze the squeezed mechanism of the in-loop photocurrent noise mentioned above and find that there is a feedback-measurement–induced anticorrelation effect between the measured photocurrent fluctuation and the amplifier dark noise, which results in the suppression of the in-loop photocurrent fluctuation below the amplifier dark noise. Our theoretical analysis gives the correlation coefficient between the photocurrent fluctuation and amplifier noise, and also yields the squeezed spectrum of the in-loop intensity fluctuation according to our experimental results.

Europhysics Letters (EPL)•Feb 1, 2000•2 citations

Sub-Poisson photo-electron statistics from a semiconductor laser with electronic feedback

James H. Churnside, Evgenii P. Gordov

We detected a portion of the output from a semi-conductor diode laser and used the detected signal as a source of negative feedback to the laser drive current. At frequencies below the characteristic frequency of the feedback loop, the power spectral density of the detected photocurrent was as much as 15 dB below the shot noise limit. This reduction can be described by a semiclassical theory of the effects of feedback on an injected shot noise current. Physically, this corresponds to a process whereby the laser output is changed in response to changes in the noise current.

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

Photocurrent shot-noise suppression is observed in closed optoelectronic loop below the limit (1 − η) of standard shot-noise level (SNL) imposed by conventional theory of photodetector with quantum efficiency η. Experimental results on photocurrent noise are presented for different values of feedback strength and quantum efficiency η of in-loop photodiode. It is shown that at fixed feedback strength the suppression factor does not depend on η. Minimum noise spectral density is observed below the SNL by a factor 17·8 (− 12·5 dB). Such large suppression cannot be explained in terms of an ordinary sub-Poissonian light state in the loop. We suggest the concept of an anticorrelation light state, where the light in the loop is described as a non-stationary state with Poissonian quantum fluctuations, and superimposed anticorrelated classical fluctuations. While the degree of noise reduction in the photocurrent can be arbitrary large, the degree of anticorrelation between the classical and quantum fluctuations in the light beam remains limited by the quantum efficiency of the feedback photodiode. Calculations based on this concept are in a good agreement with experimental data on super-shot-noise power, obtained for the beam extracted from the loop by a beam splitter.

We examine the quantum-limited behavior of an electro-optical intensity feedback loop and present a simple theory and experimental data showing excellent agreement. We show that, although the light incident upon the in-loop detector may be sub-Poissonian, this light has unique properties different from those of a freely propagating beam of intensity squeezed light. We support this by presenting the results of homodyne measurements of the phase noise of light extracted from the loop. The utility of the in-loop field is discussed, and it is shown that in all cases in which linear optical components are used, no advantage in signal-to-noise ratio is gained by taking measurements by using this light rather than a coherent source. We also discuss effects seen in the extracted or out-of-loop light. We demonstrate the existence of, and derive an expression for, an optimum gain for suppressing low-level classical noise. Conversely, in the high-gain limit, we demonstrate that the extra noise seen in the out-of-loop photocurrent that is due to the feedback process is expressible purely in terms of the mean photocurrents involved. Lastly, we introduce the novel concept of using an intensity feedback loop in conjunction with a squeezed source and show that the feedback loop has the capability of electronically transferring squeezing from one light beam to another.

Suppression of the closed-loop photocurrent fluctuation below the amplifier dark noise was observed in both a negative-feedback light-emitting diode and a laser diode. We apply the concept of an anticorrelation light state proposed by Masalov et al to analyze the anticorrelation effect between the measured photocurrent fluctuation and the amplifier dark noise, which successfully explains our experimental observations. Our theoretical analysis also yields the squeezed spectrum of the light intensity fluctuation in the loop and the correlation coefficient between the photocurrent and the amplifier noise.

The author reviews methods for generating sub-Poissonian light and related concepts. This light has energy fluctuations reduced below the level which corresponds to a classical Poissonian process (shot-noise level). After an introduction to the concept of nonclassical light, an overview is given of the main methods of quantum-noise reduction. Sub-Poissonian processes are exemplified in different areas of optics, ranging from single-atom resonance fluorescence to nonlinear optics, laser physics, and cavity quantum electrodynamics. Emphasis is placed on the conceptual foundations, and on developments in laser theory that lead to the possibility, already demonstrated experimentally, of linewidth narrowing and sub-Poissonian light generation in lasers and masers. The sources of quantum noise in these devices are analyzed, and four noise-suppression methods are discussed in detail: regularization of the pumping, suppression of spontaneous-emission noise, nonadiabatic evolution of the atomic variables, and twin-beam generation.

Suppression of in-loop photocurrent fluctuation below the amplifier dark noise was observed in both a negative-feedback light-emitting diode (LED) and a laser diode (LD). We use a new semiclassical model to analyze the squeezed mechanism of the in-loop photocurrent noise mentioned above and find that there is a feedback-measurement–induced anticorrelation effect between the measured photocurrent fluctuation and the amplifier dark noise, which results in the suppression of the in-loop photocurrent fluctuation below the amplifier dark noise. Our theoretical analysis gives the correlation coefficient between the photocurrent fluctuation and amplifier noise, and also yields the squeezed spectrum of the in-loop intensity fluctuation according to our experimental results.

We detected a portion of the output from a semi-conductor diode laser and used the detected signal as a source of negative feedback to the laser drive current. At frequencies below the characteristic frequency of the feedback loop, the power spectral density of the detected photocurrent was as much as 15 dB below the shot noise limit. This reduction can be described by a semiclassical theory of the effects of feedback on an injected shot noise current. Physically, this corresponds to a process whereby the laser output is changed in response to changes in the noise current.