Thermal dissipation effects of the entangled photon generated by four-wave mixing process in a nonlinear ring resonator

We firstly analyze the thermal dissipation effects of the entangled photons generated by a nonlinear optical ring resonator. To obtain the corresponding equation of motion of the entangled photons generated by a four-wave mixing process within the system, we propose the Markov approximation to repel the reservoir operators. The system master equation in the interaction picture for both degenerate and non-degenerate cases is analyzed and obtained. The established system can be used to characterize the optimum entangled photons in some cases where the thermal dissipation effects may be introduced noise into the system. In this work, the entangled photons can be generated into two forms, firstly, the two entangled photon states is generated, the other, the four entangled photon states can be easily obtained. Results obtained have shown that the optimum entangled photon in term of entangled photon visibility can be compensated (i.e. unchanged) under thermal dissipation effects.     

Entangled photon states generation and regeneration using a nonlinear fiber ring resonator

We propose a simple system of the entangled photon states generation and regeneration using a standard diode laser, a Mach Zehnder Interferometer (MZI) and a fiber optic ring resonator (FORR). Light from the diode laser is launched into an MZI and circulated in the FOOR, without any optical pumping components included in the system. The nonlinear light pulses are generated by a Kerr nonlinear effects type, while the resonance peaks are formed by the four-wave mixing of light pulses in the FORR. The entangled photons can be performed by using the polarization control device, and then detected by the avalanche photo-detectors, where the entangled photon visibility is plotted and seen. Similarly, the entangled photon states can be easily formed by using the appropriated coupling ratios into a fiber coupler, then into a ring resonator, i.e. without an MZI. The use of the entangled photons generation based on a fiber optic scheme for quantum teleportation, quantum key distribution via optical wireless link, and the system of the entangled photon states recovery by using a fiber ring resonator incorporating an erbium-doped fiber (EDF) have been investigated and discussed. The feasibility of dense coding using multi-entangled photons generation based on the fiber optic scheme and the effect of the entangled state walk-off along the optical fiber are also discussed, respectively.     

An investigation of the entangled photon walk-off compensation generated by a fiber ring resonator

We firstly present an experimental investigation of the entangled photon states’ recovery using a fiber optic ring resonator incorporating an erbium-doped fiber amplifier (EDFA). The weak light entangled photons can be recovered in both amplitude and states after the optical pumping and polarization control parts are used in the system. A new experimental result of the investigation of thermal effects on the entangled states’ walk-off and compensations has shown that the entangled photon walk-off compensation is achieved by using a pair of polarization control devices. The relationship between thermal effects and the entangled states’ phase shift is investigated and discussed. The walk-off compensation due to temperature changes from 30 to 80 °C is achieved. This shows that the changes in phase of the entangled photons can be negligible when the compensation is employed.     

Quantum state discrimination and enhancement by noise

Discrimination between two quantum states is addressed as a quantum detection process where a measurement with two outcomes is performed and a conclusive binary decision results about the state. The performance is assessed by the overall probability of decision error. Based on the theory of quantum detection, the optimal measurement and its performance are exhibited in general conditions. An application is realized on the qubit, for which generic models of quantum noise can be investigated for their impact on state discrimination from a noisy qubit. The quantum noise acts through random application of Pauli operators on the qubit prior to its measurement. For discrimination from a noisy qubit, various situations are exhibited where reinforcement of the action of the quantum noise can be associated with enhanced performance. Such implications of the quantum noise are analyzed and interpreted in relation to stochastic resonance and enhancement by noise in information processing.     

Thermal dissipation effects of the entangled photon generated by a nonlinear ring resonator

We firstly analyze the thermal dissipation effects of the entangled photons generated by a nonlinear optical ring resonator. To obtain the corresponding equation of motion of the entangled photons generated by a four-wave mixing process within the system, we propose the Markov approximation to repel the reservoir operators. The system master equation in the interaction picture for both degenerate and non-degenerate cases is analyzed and obtained. The established system can be used to characterize the optimum entangled photons in some cases where the thermal dissipation effects may introduce noise into the system. In this work, the entangled photons can be generated into two forms, firstly, the two entangled photon states are generated and, the other, the four entangled photon states, can be easily obtained. Results obtained have shown that the optimum entangled photon in terms of entangled photon visibility can be compensated (i.e. unchanged) under thermal dissipation effects.     

Enhanced four-wave mixing in a high-finesse highly nonlinear fiber Fabry-Perot resonator

We have achieved a four-wave mixing process in a high-finesse highly nonlinear fiber Fabry-Perot resonator, where the amplified signal and idler were enhanced in transmission by 6 dB and 10 dB respectively comparing with those in a single fiber. We used a 6 m long low-loss Fabry-Perot resonator with two high-reflectivity fiber Bragg gratings written directly into a highly nonlinear fiber provided by Sumitomo Electric Inc., where the minimised intracavity loss resulted in the finesse in excess of 100. The resonator length was locked for 30 min by means of a modified Pound-Drever-Hall technique. The maximum intracavity power was increased by 14.3 dB by increasing the stimulated Brillouin scattering threshold with periodic phase modulation by a pseudo-random bit sequence, with length matching that of the cavity.     

Broadband source generated by stimulated Raman scattering and four-wave mixing in a highly nonlinear optical fiber ring cavity

A novel high-power broadband source based on the combined action of stimulated Raman scattering and parametric four-wave mixing in a highly nonlinear dispersion-shifted fiber ring cavity is investigated experimentally. An output spectrum of 1510-1580 nm with a stable power of 91 mW is demonstrated with a dual-wavelength pumping scheme.     

Relative intensity noise induced by four-wave mixing in the case of two-wave transmission in an optical fiber

Four-wave mixing (FWM) is a significant nonlinear effect in wavelength division multiplexing (WDM) fiber-optic systems. For two-wave transmission, it is easily found that the FWM noise power decreases with frequency spacing and increases with signal power. However, the variation of relative intensity noise (RIN) with frequency spacing and signal power is only 2 dB at most. The intensity fluctuations induced by the energy exchange between the FWM generated new waves and the original ones are trivial and the influence of FWM on RIN can be neglected. It is also found that the increase of RIN with signal power is mainly attributed to stimulated Brillouin scattering (SBS) rather than FWM.     

A quantum-chaotic encoding system using an erbium-doped fiber amplifier in a fiber ring resonator

This paper firstly presents a new concept of quantum-chaotic encoding of light traveling in a fiber optic ring resonator. The pumping input power can be controlled to generate the chaotic behavior of the circulated light within the fiber ring resonator. The Kerr nonlinear type of light circulating in a fiber optic ring resonator is induced and the superposition i.e. four-wave mixing of the propagating waves at resonance occurred. The output signals can be used to generate two different codes, of which one is the quantum bits i.e. code, the other is the chaotic signal i.e. code. The proposed system has shown the potential of using for communication security, where the double security via quantum-chaotic can be performed.     

Reduced threshold of a stimulated four-wave mixing process in an optical fiber

The possibility for all-optical control of the effective parametric Stokes gain was demonstrated in an optical fiber. For the first time the threshold reduction induced by the interference of two different four-wave mixing processes which share a common Stokes wave was used as a control mechanism.     

Photons trapping within a nano-ring resonator controlled by light

We propose the interesting results that a bright and dark soliton pulse can be localized within a nonlinear nano-waveguide. The system consists of nonlinear micro- and nano-ring resonators, whereas the soliton pulse can be input into the system and trapped within the nano-waveguide. A soliton input is chopped by the nonlinear effects known as chaos into smaller pulses. The required pulse is filtered and amplified, which can be controlled and localized within the nano-waveguide. The localized bright and dark solitons are trapped within a nano-waveguide by controlling the nano-waveguide input power, which means that the photons trapping is controlled by light.     

Quantum interferences in four-wave mixing processes inside a cavity driven by quantized fields

Interferences in the quantum fluctuations of the output fields are demonstrated in four-wave mixing processes inside a cavity,which is driven by two quantized fields at the signal and the idler frequencies.These interferences depend on the phase fluctuations of the input fields and induce mode splitting in the transmission spectra.     

An investigation of quantum-chaotic signals generation using a fiber ring resonator and an add/drop multiplexer

We successfully generate the double security using a fiber ring resonator incorporating an add/drop device, whereas the quantum-chaotic encoding of light in a single fiber ring resonator is constructed. In the experiment, the nonlinear Kerr effects in the fiber ring resonator induced the chaotic wave form within the fiber ring resonator, which could be used to scramble or encode into the original signals. The laser input power used was 15 mW, with a fiber ring radius of 50 cm. We found that the double security can be formed, where the randomly polarized photons could be controlled by using the polarization controller and observed.     

A simple analytic model for noise shaping by an optical fiber Raman generator

An analytic model for first Stokes–Raman generation in optical fiber is used to evaluate the relative importance of quantum initiation noise and amplified classical pump noise in recent experiments on noise shaping. The model accounts for pump depletion and for fluctuations arising from the spontaneous generation of the first Stokes pulse, but not for scattering into higher-order Stokes pulses. The model reproduces the qualitative features of the measured first Stokes pulse energy statistics using realistic parameter values.     

Stationary Probability Distribution of Colored noise Saturation Model for a Single mode Dye Laser

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Coherence resonance induced by non-Gaussian noise in a deterministic Hodgkin-Huxley neuron

In this paper, we report a novel effect of a particular kind of non-Gaussian noise (NGN), especially its deviation from Gaussian noise, on the spiking activity in a deterministic Hodgkin-Huxley (HH) neuron. It is found via numerical simulations that the coefficient of variation (CV), characterizing the spiking regularity, nonlinearly changes with varying deviation and passes through a minimum at an optimal deviation value, representing the presence of the coherence resonance (CR). This phenomenon shows that, when the NGN is optimal, the neuron can exhibit the most regular firing behavior. This result provides a constructive role of the NGN in the timing precision of information processing and signal transduction in neural systems.     

Stochastic resonance in a single-mode laser driven by quadratic pump noise and amplitude-modulated signal

This paper investigates the phenomenon of stochastic resonance in a single-mode laser driven by quadratic pump noise and amplitude-modulated signal. A new linear approximation approach is advanced to calculate the signal-to-noise ratio. In the linear approximation only the drift term is linearized, the multiplicative noise term is unchangeable. It is found that there appears not only the standard form of stochastic resonance but also the broad sense of stochastic resonance, especially stochastic multiresonance appears in the curve of signal-to-noise ratio as a function of coupling strength λ between the real and imaginary parts of the pump noise.     

Stimulated Raman scattering and four-wave Raman mixing seeded by a supercontinuum generated in dibromomethane using picosecond and femtosecond laser sources

Stimulated Raman emission from liquid dibromomethane (vibrational Raman shift frequency, 588 cm⁻¹) is introduced into hydrogen gas (rotational Raman shift frequency, 587 cm⁻¹) as a seed beam, in order to generate numerous rotational lines by four-wave Raman mixing. Unexpectedly, a supercontinuum, which is generated by self-phase modulation in dibromomethane, acted as a seed beam to exclusively generate vibrational lines; the rotational lines are generated only when the supercontinuum is minimal. The former is explained by a competition between the high-gain vibrational and low-gain rotational Raman effects when strongly seeded by a supercontinuum. The latter is explained by stimulated Raman gain under the seed effect exclusively to the first-Stokes rotational line.     

Geometric phase of a qubit driven by a phase noise laser under non-Markovian dynamics

Robustness of the geometric phase (GP) with respect to the environmental effects is a basic condition for an effective quantum computation. Here, we study quantitatively the GP of a two-level atom system driven by a phase noise laser under non-Markovian dynamics in terms of different parameters involved in the whole system. We find that with the change of the damping coupling, the GP is very sensitive to its properties exhibiting long collapse and revival phenomena, which play a significant role in enhancing the stabilization and control of the system dynamics. Moreover, we show that the GP can be considered as a tool for testing and characterizing the nature of the qubit–environment coupling. Due to the significance of how a system is quantum correlated with its environment in the construction of a scalable quantum computer, the entanglement dynamics between the qubit with its environment under external classical noise is evaluated and investigated during the time evolution.