The key of analyzing the light signal transmitting in fiber is the interaction and correlation between them. At present, we must consider the medium and the light field as one united system. Its strict physical theory is the quantum electrodynamics (QED), to process the light field and medium to second quantization. The quantum theory is considering both the medium and the light field as quantum wave function, so we can discuss the extreme limit frequency and distance. In the analyzing of extreme limit frequency, we can get it by considering two situations: the first is the photoelectric effect between light signal and fiber medium, the second is the transmission effect of high frequency incident light. In the analyzing of extreme limit of light signal distance, we will consider the interaction of the electron and the light field. We apply the theory and formula of scattering section. We analyze the colliding mechanism of particles in medium. We calculate the transmitting situation of photon energy according the energy and momentum reservation laws. According to the maximum frequency shift of light which is allowed by optical receiver, we can get the extreme limit distance of signal transmitting.
The key of analyzing the light signal transmitting in fiber is the interaction and correlation between them. At present, we must consider the medium and the light field as one united system. Its strict physical theory is the quantum electrodynamics (QED), to process the light field and medium to second quantization. The quantum theory is considering both the medium and the light field as quantum wave function, so we can discuss the extreme limit frequency and distance. In the analyzing of extreme limit frequency, we can get it by considering two situations: the first is the photoelectric effect between light signal and fiber medium, the second is the transmission effect of high frequency incident light. In the analyzing of extreme limit of light signal distance, we will consider the interaction of the electron and the light field. We apply the theory and formula of scattering section. We analyze the colliding mechanism of particles in medium. We calculate the transmitting situation of photon energy according the energy and momentum reservation laws. According to the maximum frequency shift of light which is allowed by optical receiver, we can get the extreme limit distance of signal transmitting.
As is well known, quantum optics has developed significantly in recent years and advanced several hot research topics, such as quantum communications, quantum sensing, quantum calculations, etc. Among these researches, it is important to understand the quantum information transmitting in optical fiber. For realizing longer transmission distance and better transmission quality, great effort has devoted to the researches of encoding and decoding at the transmitter and the receiver end. However, less attention was paid to the fading of signal in the transmission channel. In this work, we mainly focus on the transmission model of optical quantum transmission and the influences of loss, dispersion and nonlinear effect on fiber transmission of optical quantum information are also discussed.Quantum information transmission can be influenced by loss, dispersion and nonlinear effect in optical fiber, leading to transmission state evolution and energy transfer. Based on the transmission equation of single mode fiber and quantum theory of electromagnetic field, the fundamental mode field of single mode fiber is quantized. A quantum transmission equation is deduced from the classical optical transmission equation through quantizing the amplitude of electromagnetic field. Compared with classic wave theory, the photon transmission equation quantizing the slowly-varying amplitude in the coupled nonlinear Schrdinger equation is obtained. In the classic wave equation, light is interpreted as energy which propagates as waves. The photon transmission equation is obtained by quantizing the slowly-varying amplitude of light, that is, the particle nature of light. The energy propagates through alternative interaction between creation and annihilation operator on photons. The transmission equations show that photons will interact with the transmission medium during propagation and be influenced by dispersion, nonlinear effect, loss, etc. By giving a trail solution and introducing a perturbation term, the transmission equation is solved for the complicated case where the dispersion, loss and nonlinear effect are all involved. A dispersion equation that should be satisfied for nontrivial solution is then obtained. From this dispersion equation, the relation between photon power and perturbation frequency is calculated and analyzed. The change of photon power in generalized field with perturbation frequency is discussed, and the influences of fiber dispersion and nonlinearity on the solution are analyzed.Some conclusions are obtained by perturbed solution and analyses of single photon transmission equation in optical fiber. It is found that photon power decreases with the increase of perturbation frequency and reaches its maximum value for zero perturbation frequency. At the same time, the optical power is affected by the dispersion of the optical fiber. Photon power decreases with the GVD coefficient far from the zero dispersion point. It is also found that photon power decreases with the increase of nonlinear coefficient. This work may contribute to the research of the properties of quantum fiber transmission system.
The development of communication technology is currently progressing at an extremely rapid pace. One of the most widely applied technologies for data transmission is fiber optic communication, which uses light as the transmission medium. This technology enables data to be transmitted at very high speeds. However, in the process of data transmission, a security mechanism is required to protect information from unauthorized access. Attacks on fiber optic networks can lead to significant alterations in the data received compared to the data sent by the transmitter. This poses a serious risk, particularly when the transmitted data is confidential. Two methods that can be employed to secure fiber optic networks are Optical Steganography and Optical Encryption. The working principle of Optical Steganography involves hiding signals in public channels, while Optical Encryption functions by encrypting the transmitted signals. Both methods can be implemented using OptiSystem software. According to the results of this study, Optical Encryption demonstrates a higher level of reliability compared to Optical Steganography. Optical Encryption achieved a Q-Factor value of 14.65 and a BER of 6.55×10−49. In terms of Q-Factor, Optical Encryption is shown to be 16.3% more effective than Optical Steganography and 90.4% more efficient compared to designs without a security system.
The transmission of light through optical fibre has traditionally been governed by classical electromagnetic theory. However, increasing interest in quantum communication, quantum-limited amplification, and photonic quantum technologies necessitates a quantum mechanical treatment of guided light. This study presents a theoretical investigation into the application of quantum field theory and quantum noise models to light propagation in optical fibres. We formulate a quantized waveguide model, examine decoherence and photon statistics, and analyse implications for quantum communication and sensing. The results demonstrate that quantum theoretical approaches provide deeper insights into noise limits, entanglement preservation, and nonlinear photon interactions, offering pathways for next-generation quantum-enabled fibre networks.
One of the most intriguing quantum phenomena of light is the wave–particle duality which is related to the inability of the classical wave and particle concepts to fully describe the behavior of quantum objects. Theoretically, the wave features of the electromagnetic field, such as interference, follow from the solution of Maxwell's equations while particle features are a consequence of the field quantization, in which the electromagnetic field is described to consist of discrete energy packets, photons. Due to the wave–particle duality, for example, simultaneous description of optical absorption, emission, and interference of propagating fields has conventionally not been considered feasible using local optical models but has required using Maxwell's equations with stochastic source terms accounting for the wave–particle duality. Also the description of the momentum of light in a medium has been problematic.
In the research described in this thesis, the quantized fluctuational electrodynamics (QFED) model is derived based on combining the electromagnetic Green's functions to the field quantization to describe the position dependence of the photon number and local thermal balance in general non-equilibrium conditions, and to separate the electromagnetic field into parts propagating in different directions in resonant structures, which has conventionally been problematic due to interference effects. The QFED method is shown to resolve the previously found anomalies in the canonical commutation relations of photon ladder operators. The QFED method is also used to derive quantum optical field–matter interaction parameters fully capturing the interference, emission, damping, and scattering of propagating photons in stratified media leading to an interference-exact radiative transfer equation (RTE) model. Therefore, the derived interaction parameters solve the problem of simultaneously describing interference and losses in the widely used RTE framework.
The particle aspects of light are also studied by directly applying the conservation laws of nature and the special theory of relativity to show that light propagating in a medium must be described as mass-polariton (MP) quasiparticles, covariant coupled states of the field and matter. These quasiparticles are shown to have momentum of the Minkowski form and a nonzero mass that is carried by a mass density wave associated with light. The field–matter interaction related to the MP quasiparticles also leads to the dissipation of photon energy. These particle model results are also derived using a wave-based optoelastic continuum dynamics (OCD) approach following from the electrodynamics of continuous media and the continuum mechanics. The obtained results verify the full agreement between the wave and particle models when they are correctly applied. The key finding that a light pulse propagating in a medium is inevitably associated with an experimentally measurable mass implies a fundamental change in the prevailing perceptions of light.; Eras kiehtovimmista valon…
According to an entropy approach and by reviewing the similarity between laws characterizing the flow of heat and electric charges, electric charges were defined as electromagnetic waves that possess an electrical potential or simply as ionized photons. Accordingly, the flow of electrons was defined as a simultaneous flow of particulate energy and wave energy. Such definitions led to clear the confusions of duality properties of electrons and light waves, conflicts in the SI system of units and to explain the difference between the calculated drift speed of electrons and the speed of electricity or charges in conductors. However, Einstein considered the electron to be a negative charge of unknown nature during his analysis of the photoelectric effect. Einstein presented his hypothesis that light may behave as a particle to find a plausible explanation of the photoelectric effect. He found the measured cutoff frequency of light below which light might not eject electrons from metal-surfaces in photocells regardless of how much light is shone on the surface as a proof of truth of his hypothesis. Such frequency may be explained also, according to the previously introduced definitions, as the minimum energy quanta that may gain a quantized potential in photocells. This explanation may find plausible explanations of the found measurements of the photoelectric effects for different metal surfaces, stopping voltages into photocells and the photoelectric effect of X-rays. Einstein’s hypothesis of the photoelectric effect failed to find plausible explanations of such measurement results. According to the principles of conservation of momentum, there is a minimum quantity of photons that may lead to bouncing an atomic electron out of its orbit. So, considering Einstein’s theory as a perfect hypothesis that explains the photoelectric effect may be a misconception.