Optical Fiber Transmission Line Research Articles

Study of pulsed radiation by the collective coordinates method

We examine the feasibility of analyzing the behavior of a radiating pulse during its propagation in an optical fiber transmission line by the collective coordinates approach. We show that once the waves radiation are created, their dynamics is well described by the variational equations. We also show that, these waves of radiation do not keep a constant profile during their propagation, but are spread out continuously. Their frequency remains constant and is compared to the carrying frequency at a variation ranging between GHz and THz. The precise knowledge of the frequency or the temporal position of the radiation allows us to consider the possibility of removing the radiation in one operation by spectral or temporal filtering.

INVESTIGATION OF ADDITIONAL LOSSES OF FIBER-OPTIC CONDUCTORS OF TYPE G-652 THAT OCCUR DURING BENDING

One of the problems of modern information transmission systems is the introduction of new methods of protecting information transmitted over fiber-optic transmission lines. Currently, new methods of unauthorized access are emerging, which are being improved and developed every year. Within the framework of this work, studies of additional losses during bending of the optical fiber were carried out in order to create an automatic control system for additional losses that occur during mechanical action leading to its bending. For this purpose, practical experiments were conducted to measure losses in optical fiber with multiple bends and a computer program was created based on the data obtained. With the help of this program, it is possible to estimate additional losses in the optical fiber when the wavelength changes from 1310 to 1625 nm and the bending angle indicators from 45 to 135 degrees. The program also allows you to automatically approximate the values of additional losses occurring in the optical fiber with different variations of different bending angles and their number. The study of additional losses will allow in the future to develop an automatic control system based on changes in the indicators of additional losses and, when they change, issue a warning signal about possible unauthorized connection to a fiber-optic cable.

Power spectral density analysis of relative comb-line phase jitter in a twin-soliton molecule

Investigation on the relative phase evolution between two bounded optical solitons is essential for its potential applications in development of larger telecommunication capacity of optical fiber transmission lines, resolution improvement in advancing ultrafast characterization approaches and development of all-optical information storage. Here we characterized relative comb-line phase jitter power spectral density (PSD) of a soliton molecule pair generated from a passively mode-locked Er:fiber laser. Through tracking the intensity difference between two selected wavelengths in one certain spectral interference fringe, the relative comb-line phase noise PSD is measured by balanced detection. The estimated measurement resolution is at 10−14 rad2/Hz level and the estimated integrated phase noise from 10 MHz to 100 Hz is 2.04 mrad. The estimated relative linewidth is far below 1 mHz. Comparison between phase noise PSD and intensity noise PSD indicates that AM–PM conversion plays an important role in relative phase jitter dynamics between the two solitons. Our spectral interference fringe tracking technique is attractive for its simplicity and shows potential in ultra-high resolution in phase noise measurement, providing an ultra-sensitive alternative approach for relative phase noise stabilization of optical soliton molecules, two independent mode-locked lasers and optical length stabilization of interferometers.

Holography, and the future of 3D display

The pioneers of holography, Gabor, Leith, Upatnieks, and Denisyuk, predicted very early that the ultimate 3D display will be based on this technique. This conviction was rooted on the fact that holography is the only approach that can render all optical cues interpreted by the human visual system. Holographic 3D displays have been a dream chased after for many years, facing challenges on all fronts: computation, transmission, and rendering. With numbers such as 6.6 × 1015 flops required for calculations, 3 × 1015 b/s data rates, and 1.6 × 1012 phase pixels, the task has been daunting. This article is reviewing the recent accomplishments made in the field of holographic 3D display. Specifically, the new developments in machine learning and neural network algorithms demonstrating that computer-generated holograms approach real-time processing. A section also discuss the problem of data transmission that can arguably be solved using clever compression algorithms and optical fiber transmission lines. Finally, we introduce the last obstacle to holographic 3D display, which is is the rendering hardware. However, there is no further mystery. With larger and faster spatial light modulators (SLMs), holographic projection systems are constantly improving. The pixel count on liquid crystal on silicon (LCoS) as well as microelectromechanical systems (MEMS) phase displays is increasing by the millions, and new photonic integrated circuit phased arrays are achieving real progress. It is only a matter of time for these systems to leave the laboratory and enter the consumer world. The future of 3D displays is holographic, and it is happening now.

Dual port mach-zehnder modulator in fiber-optic transmission lines of radio frequency signals

Dual port mach-zehnder modulator in fiber-optic transmission lines of radio frequency signals

Energy Loss during Splitting of Two Optical Fibers, One of Which is Elliptically Deformed at the Joint

Two fragments of a fiber-optic data transmission line are considered round and elliptical (at the junction) in their cross section. For a single-mode operation, analytical expressions are obtained for the energy losses when connecting two such fragments. It is shown that energy losses increase with increasing eccentricity and simultaneously decrease with increasing waveguide number.

Data acquisition system for capacitive energy storages

Failures in capacitive energy storages result in destruction of faulty elements and other expensive components. Recovery of such failures requires long-term and expensive works to replace and to restore elements of the capacitive energy storage. Diagnostic hardware of the capacitive energy storages makes it possible to limit the consequences of such failures, to reduce the frequency of their occurrence, as well as to monitor the equipment and transmit information on functioning of the pulse current sources to the facility. The operation of data acquisition system in high voltage facilities is accompanied by the electromagnetic interference, and it is therefore necessary to provide the optical fiber transmission lines, the isolation of the diagnostics hardware components and galvanic isolation of their power supply.

Features of construction of the scheme of fiber-optic communication system for transmission of analog signals in the frequency range from 0.135 to 40 GHz

The paper presents the design of a fiber-optic microwave signal transmission line. The use of the developed design of a fiber-optic microwave transmission line allows the radar operating frequency range to be at least doubled. In addition, the number of functional blocks is reduced to ensure the operation of the radar in this frequency range. The results of experimental studies are presented.

Comparing methods of controlling unauthorized access to fiber-optic transmission lines

In present day telecommunication systems the topical problem is protection of the subscribers’ personal data against possible thefts and hacking fiber-optic information transmission guide lines, as this causes a number of dangerous situations and problems. The attackers, in spite of the legislative framework for the information protection, are still trying to read information from a fiber-optic transmission line (FOTL). This possibility arises due to incorrect installation and configuration of error protection, unauthorized access to information is possible. This article discusses two methods of detecting unauthorized admission (unauthorized access). The results of the study using an optical laser radiation source and power meter, as well as a YOKOGAWA optical reflectometer are presented. As a result, it was concluded that the method of preventing unauthorized access at the wavelength of 1625 nm can be used, since continuous FOTL monitoring will not interfere with the traffic.

Comparison of Photonic Reservoir Computing Systems for Fiber Transmission Equalization

In recent years, various methods, architectures, and implementations have been proposed to realize hardware-based reservoir computing (RC) for a range of classification and prediction tasks. Here we compare two photonic platforms that owe their computational nonlinearity to an optically injected semiconductor laser and to the optical transmission function of a Mach-Zehnder modulator, respectively. We numerically compare these platforms in a delay-based reservoir computing framework, in particular exploring their ability to perform equalization tasks on nonlinearly distorted signals at the output of a fiber-optic transmission line. Although the non-linear processing provided by the two systems is different, both produce a substantial reduction of the bit-error-rate (BER) for such signals of up to several orders of magnitude. We show that the obtained equalization performance depends significantly on the operating conditions of the physical systems, the size of the reservoir and the output layer training method.

Monitoring a Laser-Pulse Front Profile with a Picosecond Resolution and a Wide Dynamic Range at Multichannel Facilities

The results of the development of a technique for measuring the power contrast of a laser pulse by registering the pulse-front profile with a large dynamic range are presented. The technique was developed on the basis of a high-speed streak camera and fiber-optic transmission lines; it provides the following registration parameters: the dynamic range of measuring the laser-pulse power contrast at the wavelength λ = 0.53 µm is 107, while the temporal resolution of the registration channel is no worse than 60 ps. A method of increasing the power contrast to 1011 using an optical scheme based on elements with nonlinear transmission is shown.

Modelling the Relationship Work-Family Conflict with Job Incidents to Mediating of Stress (Case Study: Light Fiber Project of Tehran-Shahrood)

Background: Work-family conflict, as a social parameter, can affect the concentration of individuals and the health of workers. Objectives: The purpose of this study was to provide a model of work-family conflict theory and occupational accidents by taking into account important parameters such as job stress in one of the optical fiber transmission line projects. Methods: The statistical population of the study was the staff of Tehran-Shahrood optical fiber transmission line. The present study was a correlational study on the descriptive/analytical cross-sectional type. A total of 225 individuals were selected as the statistical population. The 4-part questionnaire, including demographic questions, 18 questions regarding work-family conflict, 15 questions regarding job stress, and 39 questions regarding occupational accident were completed by the subjects. Data obtained from this study were analyzed by the PLS-SEM software, and the corresponding model was presented. Results: The results of the study indicated that the proposed model well covered the indices of fit, and the factor loading of all parameters was significant. In addition, high-coefficient job stress could affect accident susceptivity and accident occurrence. Conclusions: The reduction of work-family conflict, as a social indicator, which is a prerequisite for stress occurrence, can be effective in reducing the rate of occupational accidents, and the management system of organization can improve the safety level of the employees through optimal management of this important factor.

Soliton content in the standard optical OFDM signal.

The nonlinear Schrödinger equation (NLSE) is often used as a master path-average model for fiber-optic transmission lines. In general, the NLSE describes the co-existence of dispersive waves and soliton pulses. The propagation of a signal in such a nonlinear channel is conceptually different from linear systems. We demonstrate here that the conventional orthogonal frequency-division multiplexing (OFDM) input optical signal at powers typical for modern communication systems might have soliton components statistically created by the random process corresponding to the information content. Applying the Zakharov-Shabat spectral problem to a single OFDM symbol with multiple subcarriers, we quantify the effect of the statistical soliton occurrence in such an information-bearing optical signal. Moreover, we observe that at signal powers optimal for transmission, an OFDM symbol incorporates multiple solitons with high probability. The considered optical communication example is relevant to a more general physical problem of the generation of coherent structures from noise.

Методы создания магистральных оптоволоконных линий передачи данных на основе бинарных проводников и волоконно-оптических информационно-энергетических каналов

Методы создания магистральных оптоволоконных линий передачи данных на основе бинарных проводников и волоконно-оптических информационно-энергетических каналов

Behavior Monitoring Based on Intensity Matrix Distribution in Output Plane of Single-Mode Fiber Bundle

A smart structure using intensity-based optical fiber sensors has the potential to be a simple and low-cost system. In this paper, a novel fiber-optic smart structure system using a complementary metal–oxide–semiconductor (CMOS) is demonstrated that simultaneously monitors a number of hetero-core optical fiber bending sensors. The proposed system can integrate a number of optical fiber transmission lines. Therefore, the system does not require a number of photodetectors, which is different from conventional techniques. To simultaneously measure optical intensity, we coupled a number of hetero-core optical fiber sensors to a CMOS camera. The optical fiber sensor can detect macrobending to the optical light intensity. The output images comprise luminance spots distribution directly representing the sensor arrangements in the smart structure. A template matching technique based on the sum of absolute differences was introduced to distinguish between the overall behaviors of structures. A recognition experiment for object shapes was performed with a smart pressure sheet in which hetero-core optical fiber sensors are embedded as a simple case. In addition, a real-time human body posture recognition application was implemented using a fiber-optic smart clothing to apply the proposed system. Recognition results show that all images comprising luminance spots distribution were matched with the correct template images, with an error rate of 0% for 15 trials.

Chirped solitons in derivative nonlinear Schrödinger equation

The exact chirped solitons are derived from the derivative nonlinear Schrödinger equation (DNLS). The obtained chirps could help for either pulse compression or amplification in optical fiber and nonlinear electrical transmission line. The 22 new obtained chirped solitons and 22 soliton solutions of the DNLS could help in the understanding of the phenomena in which waves are governed by such equation.

Определение формы провода ЛЭП на основании вычисления по геодезическим измерениям функции ее аппроксимирующей

Abstract: Power line is a complex engineering structure, serving for power transmission from a distance. Nowadays this method of power transmission is the most financially justified for part of the cost in comparison with cable gaskets. Thereby power lines shrouded the city, as well as interconnected. And in recent years existing support are used for suspension lines (Fiber-optic transmission line). For the implementation of the suspension cable is necessary to know the existing slack wire. This article provides a rationale computation capabilities of wire marks in any migration or all of the anchor spans phase high voltage transmission lines on the measured elevations of the wire in one of the spans of the anchor section. This methodology is maximally reduced to a simple implementation method, without complex calculations, so it may be useful to professionals working in the field of research and design of power lines facing in practical activities with the need for rapid results.

An additional channel for FM signal transmission in standard fiber-optic AM communication lines

A paradigm has been developed according to which an additional FM signal transfer channel is formed in a standard optical fiber transmission line without violating the main AM channel operation. Using the proposed approach, an RS-232 interface signal has been experimentally transferred via a standard intraobject 100-Mbit Ethernet line based on an SMF-28 single-mode optical fiber.

Efficient heralding of O-band passively spatial-multiplexed photons for noise-tolerant quantum key distribution.

When implementing O-band quantum key distribution on optical fiber transmission lines carrying C-band data traffic, noise photons that arise from spontaneous Raman scattering or insufficient filtering of the classical data channels could cause the quantum bit-error rate to exceed the security threshold. In this case, a photon heralding scheme may be used to reject the uncorrelated noise photons in order to restore the quantum bit-error rate to a low level. However, the secure key rate would suffer unless one uses a heralded photon source with sufficiently high heralding rate and heralding efficiency. In this work we demonstrate a heralded photon source that has a heralding efficiency that is as high as 74.5%. One disadvantage of a typical heralded photon source is that the long deadtime of the heralding detector results in a significant drop in the heralding rate. To counter this problem, we propose a passively spatial-multiplexed configuration at the heralding arm. Using two heralding detectors in this configuration, we obtain an increase in the heralding rate by 37% and a corresponding increase in the heralded photon detection rate by 16%. We transmit the O-band photons over 10 km of noisy optical fiber to observe the relation between quantum bit-error rate and noise-degraded second-order correlation function of the transmitted photons. The effects of afterpulsing when we shorten the deadtime of the heralding detectors are also observed and discussed.

Intrachannel cross-phase modulation-induced phase shift in high-speed dispersion-managed optical fiber transmission system

We investigate the intrachannel cross-phase modulation (IXPM)-induced phase shift in optical return-to-zero pulse propagating in a periodically dispersion-managed long-haul optical fiber transmission line. Necessary dynamical equations for various pulse parameters have been derived using variational analysis to estimate the phase shift. These equations are solved by the Runge–Kutta method. The analytical result is verified by numerical simulation based on split-step Fourier method. We therefore explore the effects of various parameters, such as transmission distance, input power, duty cycle, dispersion map strength, and residual dispersion, on phase shift for a 40 Gb/s single-channel transmission system. We also check the impact of variation of bit rate on phase shift. We find that IXPM-induced phase shift can be mitigated by proper adjustment of dispersion management and different pulse parameters like duty cycle, dispersion map strength, and peak power.