Amplitude-squeezed Light Research Articles

Stochastic Model of Sub-Poissonian Quantum Light in an Interband Cascade Laser

This work theoretically investigates the possibility of generating amplitude-squeezed light with high-quantum-efficiency interband cascade lasers. Based on a stochastic approach, we show that, by employing the suppressed-pump-noise configuration, this kind of midinfrared source enables operation with considerable amplitude squeezing over a large bandwidth of several GHz. Our results facilitate future midinfrared quantum photonic applications such as free-space secure communications.

An Analytical Approach for Implementing an All-Optical NOR Operation Using Amplitude Squeezed Light

An Analytical Approach for Implementing an All-Optical NOR Operation Using Amplitude Squeezed Light

Maximizing precision in saturation-limited absorption measurements

Quantum fluctuations in the intensity of an optical probe is noise which limits measurement precision in absorption spectroscopy. Increased probe power can offer greater precision, however, this strategy is often constrained by sample saturation. Here, we analyse measurement precision for a generalised absorption model in which we account for saturation and explore its effect on both classical and quantum probe performance. We present a classical probe-sample optimisation strategy to maximise precision and find that optimal probe powers always fall within the saturation regime. We apply our optimisation strategy to two examples, high-precision Doppler broadened thermometry and an absorption spectroscopy measurement of Chlorophyll A. We derive a limit on the maximum precision gained from using a non-classical probe and find a strategy capable of saturating this bound. We evaluate amplitude-squeezed light as a viable experimental probe state and find it capable of providing precision that reaches to within > 85% of the ultimate quantum limit with currently available technology.

Analytical approach of reduction in bit error rate using amplitude-squeezed states of light

In optical communication, bit error rate (BER) is a real problem today. In communication with coherent light, there is a limitation in reduction in BER due to inherent statistical property of light. Noise level produced by amplitude-squeezed light is below the shot noise level which is called quantum limit of noise. So if the encoding is done by amplitude-squeezed states of light, then one can overcome the limitation significantly. In this paper, we have shown analytically that using amplitude-squeezed sates of light a massive reduction in BER is possible.

Plasmonic op-amp circuit model using the inline successive microring pumping technique

The electro-optic power pumping system model using the inline successive technique within the modified add-drop filter is proposed. A pumping system consists of a closed loop Panda ring resonator, from which the optical power is coupled inline into the system. By controlling the two side phase modulators, the whispering gallery mode (WGM) is generated by the amplitude-squeezed light within the modified add-drop filter. By using the proposed circuits, the low current can be applied into the system via a gold layer connection, from which the amplified output current can be obtained at the throughput port, which can be functioned as the electronic operational amplifier (op-amp). In application, the WGM output is the amplified signal that can be used for the up (down) link in free space communication network called light fidelity (LiFi). The electro-optic signals conversion can be performed by the stacked layers of silicon–graphene–gold materials. The results obtained have shown that large gain is obtained at the WGM output, which is ~ 5 × $$10^{ - 6}\; {\text{cm}}^{2} \;({\text{V}}\;{\text{sW}})^{ - 1}$$ , when the pumping saturation time is ~ 2 fs. It concludes the suitability of our proposed model for light fidelity, LiFi up-down link conversion.

New proposal of modulation of amplitude-squeezed state of light by intensity variation of a low-frequency coherent message signal Saibal Mitra and Sourangshu Mukhopadhyay

Squeezed state of light explores a new era in noiseless communication and data processing recently breaking the quantum limit of noise. We propose a new mechanism of modulating an amplitude-squeezed signal with the instantaneous intensity variation of a coherent signal. The modulating signal is a coherent light where the amplitude-squeezed light takes the role of a carrier signal.

Quantum frequency down-conversion of bright amplitude-squeezed states.

We demonstrate experimentally the quantum frequency down-conversion of a bright amplitude-squeezed optical field via a high efficiency difference frequency generation process. 532 nm amplitude-squeezed light with squeezing of 1.0 dB is successfully translated to 810 nm amplitude-squeezed light with squeezing of 0.8 dB. The effects of amplitude and phase fluctuations of the pump field on the frequency conversion are investigated both theoretically and experimentally. It is shown that the quantum frequency down-conversion is insensitive to small amplitude fluctuations of the pump field at the optimal conversion point. However, the phase fluctuations of the pump field can lead to increase of noise in the phase quadrature of the down-converted field. To eliminate the additive phase noise, a dual frequency down-converter which utilizing common pump field is proposed and demonstrated.

Long-term stable bright amplitude-squeezed state of light at 1064 nm for quantum imaging

Bright amplitude-squeezed light at 1064nm is generated with excellent long-term stability by utilizing the degenerate optical parametric amplifier (OPA) based on periodically poled KTiOPO4 (PPKTP) crystal. Amplitude noise reduction of as much as −5.5dB is observed directly at an output power of 0.3mW. This corresponds to a squeezing of −6.22dB in the beam, the detection efficiency and the propagation efficiency are taken into account. The average value of the detected noise reduction in continuous operation over 5h is −3.8dB by locking the cavity length of the OPA. The squeezed state light is applied for imaging of virtual object. The experimental results indicate that the obtained image is more distinct and has less distortion compared to that obtained by infrared coherent light.

利用自制的单频激光器获得近通讯波段正交振幅压缩态光场

利用自制的单频激光器获得近通讯波段正交振幅压缩态光场

Experimental study on the imaging of the squeezed state light at 1064 nm

Stable, low noise, infrared squeezed state tight at 1064 nm is generated by utilizing optical parametric down-conversion (OPDC) technique based on periodically poled KTiOPO4 in a optical parametric amplifier (OPA) resonator. A non-classical noise reduction of 2.58 dB below the shot noise is observed through balanced homodyne detection. The squeezed state light is used to set up an imaging system for high-resolution imaging, and it is found that the resolution of image based on the amplitude-squeezed light is 1.26 times larger than that of infrared coherent light under the same intensity. The experimental results indicate that squeezed light is an important non-classical light, which can overcome the coherent laser shot-noise, the classical diffraction limit and limit of quantum noise.

Analysis of quantum noise in a singly resonant nondegenerate optical parametric oscillator

We have analyzed the evolution of quantum operators in a three-wave mixing process by using the nonlinear polarization driven wave equations and linearization of the quantum operators. We have theoretically shown that a nondegenerate optical parametric amplifier can generate amplitude-squeezed light when operated in the backconversion regime. Furthermore, a nondegenerate optical parametric oscillator, where only the signal wave is resonant, is proved to generate amplitude-squeezed light when the pump intensity is above the value at which 100% photon conversion efficiency is achieved. The calculated limit for amplitude-squeezing in this case is 3 d B.

Bright amplitude-squeezed light generation by an optical parametric deamplifier in a periodically poled KTiOPO4 crystal

We demonstrated experimentally the generation of bright amplitude-squeezed light by a continuous-wave quasi-phase-matched degenerate optical parametric deampl ifier based on periodically poled KTiOPO4The threshold of the optic al parame tric oscillator is 35mW. With the pump power of 20mW, the amplitude noise re duction of 223dB is observed directly. It is significant that the amplitude noise reduction of 217dB can be observed only at the pump power of 8mW.

Generation of Amplitude-Squeezed Light due to Destructive Two-Photon Interference

Generation of Amplitude-Squeezed Light due to Destructive Two-Photon Interference

A portable multi-purpose non-classical light source

A compact and portable multi-purpose non-classical light source (volume about 300×400×500 mm 3 ) has been designed and built. A laser diode-pumped intracavity frequency-doubled Nd:YAP/KTP laser and a semi-monolithic non-degenerate optical parametric oscillator (NOPO) are closely integrated on an invar steel base. Above the oscillation threshold of the NOPO (∼3 mW), the twin beams with an intensity quantum correlation of 5.9 dB were obtained; when a signal of subharmonic wave, which is out of phase to the pump field, was injected into the NOPO, bright two-mode quadrature amplitude-squeezed light of 2.1 dB and an EPR beam with amplitude anticorrelation and phase correlation was produced at a pump power of milliwatt order. The features of compactness, portablility, low pump threshold, and versatility make the device useful for developing practical non-classical light sources.

Amplitude squeezing in a Mach-Zehnder fiber interferometer: Numerical analysis of experiments with microstructure fiber

We study a Mach-Zehnder nonlinear fiber interferometer for the generation of amplitude-squeezed light. Numerical simulations of experiments with microstructure fiber are performed using linearization of the quantum nonlinear Shroedinger equation. We include in our model the effect of distributed linear losses in the fiber.

Quantum measurements with an amplitude-squeezed-light beam splitter

Quantum measurement of amplitude fluctuation is performed by the injection of 2.5-dB amplitude-squeezed light produced by a quantum-well laser into the dark port of a beam splitter as the meter wave. It is shown that the measurements satisfy the criteria of quantum nondemolition measurement. The measured transfer coefficient and the quantum-state preparation ability are 1.07 and 0.8, respectively.

Application of amplitude-squeezed state light from injection-locked laser diode in quantum teleportation and dense coding

Abstract The novel quantum teleportation and dense coding systems based on applying the amplitude-squeezed state light produced from the injection-locked laser diodes and a simple direct measurement scheme for the Bell state are proposed.

Analysis of the generation of amplitude-squeezed light with Gaussian-beam degenerate optical parametric amplifiers

We investigate the generation of amplitude-squeezed states with degenerate optical parametric amplifiers that are pumped by focused Gaussian beams. We present a model that facilitates the calculation of the squeezing level for an experimentally realistic configuration in which there is a Gaussian input signal beam that has the same confocal parameter and waist location as the Gaussian pump beam, with no restriction on the interaction length-to-confocal parameter ratio. We show that the 3-dB squeezing limit that was thought to be imposed by the Gaussian pump profile can be exceeded in the (previously uninvestigated) tight-focusing regime. We find the maximum possible amplitude squeezing in this regime to be 4.65 dB. However, it is possible to increase the squeezing level further by spatially filtering the tails of the output signal beam, resulting in squeezing levels in excess of 10 dB.

Quantum teleportation and dense coding by means of bright amplitude-squeezed light and direct measurement of a Bell state

Simple schemes to realize quantum teleportation and dense coding for continuous variables are proposed, in that entangled EPR beams are produced by combining two bright amplitude squeezed beams. The measurement of the ``Bell state'' is accomplished by means of direct detection for photocurrents and two rf power splitters. As a local oscillator and balanced homodyne detector are not needed, the proposed system is easy to realize experimentally.

Generation of Tunable Amplitude-Squeezed Light by Injection Locking of a Laser Diode

Tunable amplitude squeezing around the D2 line of cesium has been experimentally accomplished at room temperature in a quantum-well laser diode with light injection from a single-mode distributed Bragg-Reflector laser diode. While the master laser frequency is tuned, amplitude squeezing of the output light from the slave laser can be maintained at about 0.9 dB throughout a tunable range of ∼ 1.7 GHz around the cesium D2 line.