Nonlinear Effects In Optical Fibers Research Articles

Optimize Nonlinear Effects on Fundamental and High-order Soliton in Photonic Crystal Fiber

Nonlinear effects in optical fibers are mainly caused by two sources: inelastic scattering behaviour or the intensity sensitivity of the medium's refractive index. The propagation process in photonic crystal fibers is more complex than the propagation process of first-order solitons, second-order solitons, and third-order solitons. This article discusses the effects of propagation on first-, second- and third-order solitons. A popular approach to supercontinuum generation through soliton fission is the higher-order soliton technique for spectral generation.

Coriolis force compensation and laser beam delivery for 100-m baseline atom interferometry

The Coriolis force is a significant source of systematic phase errors and dephasing in atom interferometry and is often compensated by counter-rotating the interferometry laser beam against Earth's rotation. We present a novel method for performing Coriolis force compensation for long-baseline atom interferometry, which mitigates atom-beam misalignment due to beam rotation, an effect which is magnified by the long lever arm of the baseline length. The method involves adjustment of the angle of the interferometer beam prior to a magnifying telescope, enabling the beam to pivot around a tunable position along the interferometer baseline. By tuning the initial atom kinematics and adjusting the angle with which the interferometer beam pivots about this point, we can ensure that the atoms align with the center of the beam during the atom optics laser pulses. This approach will be used in the MAGIS-100 atom interferometer and could also be applied to other long-baseline atom interferometers. An additional challenge associated with long baseline interferometry is that since long-baseline atom interferometers are often located outside of typical laboratory environments, facilities constraints may require lasers to be housed in a climate-controlled room a significant distance away from the main experiment. Nonlinear effects in optical fibers restrict the use of fiber-based transport of the high-power interferometry beam from the laser room to the experiment. We present the design of and prototype data from a laser transport system for MAGIS-100 that maintains robustness against alignment drifts despite the absence of a long fiber.

Mitigating stimulated Brillouin scattering in multimode fibers with focused output via wavefront shaping.

The key challenge for high-power delivery through optical fibers is overcoming nonlinear optical effects. To keep a smooth output beam, most techniques for mitigating optical nonlinearities are restricted to single-mode fibers. Moving out of the single-mode paradigm, we show experimentally that wavefront-shaping of coherent input light to a highly multimode fiber can increase the power threshold for stimulated Brillouin scattering (SBS) by an order of magnitude, whilst simultaneously controlling the output beam profile. The SBS suppression results from an effective broadening of the Brillouin spectrum under multimode excitation, without broadening of transmitted light. Strongest suppression is achieved with selective mode excitation that gives the broadest Brillouin spectrum. Our method is efficient, robust, and applicable to continuous waves and pulses. This work points toward a promising route for mitigating detrimental nonlinear effects in optical fibers, enabling further power scaling of high-power fiber systems for applications to directed energy, remote sensing, and gravitational-wave detection.

Multi-Eigenvalue Demodulation Using Complex Moment-Based Eigensolver and Neural Network

Optical eigenvalues originating in optical solitons are the potential for becoming information carriers not affected by chromatic dispersion and nonlinear effects in optical fibers. They are obtained by attributing the associated eigenvalue equations deduced by solving the nonlinear Schrödinger equation with inverse scattering transform (IST) to the matrix eigenvalue problem, and maintaining constant values regardless of the transmission distance. The eigenvalue communication systems require to solve the eigenvalues in soliton-by-soliton. While effective eigenvalue solution methods have not been studied well in telecommunication systems, one of the most well-known eigenvalue solution methods is the QZ decomposition-based method. However, the QZ algorithm requires a large complexity. To reduce the complexity, a method to demodulate the optical eigenvalues using a complex-moment eigenvalue solver (CME) was investigated. CME is a parallelizable eigenvalue solver that can extract any eigenvalue. This paper proposes a novel optical eigenvalue demodulation method that combines CME and an artificial neural network (ANN) based on employing an on-off encoded discrete eigenvalue modulation scheme. The ANN is sensitive to the input order of the units; therefore, the eigenvalues must be sorted. A lightweight sorting algorithm is hence required. In addition to the proposed scheme, this study proposes partial sorting using CME and ANN. Here, 2000 km fiber-transmission experiments for an on-off-encoded four-discrete- eigenvalue were conducted. The experimental results indicated that the proposed demodulation method obtained bit error rate (BER) characteristics comparable to conventional methods by devising an extraction range of eigenvalues in CME.

Discrete optical solitons: Perspectives and new trends

Fifty years ago, in 1973 temporal optical solitons were predicted by Hasegawa and Tappert, highlighting the possibilities of balancing dispersive and nonlinear effects in optical fibers. The next decade followed by similar advances on spatial and discrete solitons. This article brings perspectives and current research on topological photonics.

Analysis and Evaluation of Different Compensation Techniques for Fiber Losses

The Linear and nonlinear effects in optical fibers are very important and influential factors that effect on the power of the signal transmitted within the optical fiber. In this paper, the mathematical model for these effects was presented. The most important methods used to compensate these losses were also reviewed. The compensation methods reviewed include various linear and nonlinear effects most of the methods reviewed focused on increasing the length of the optical fiber to transmit the signal with the least consumed power and high data transfer rate at low design cost

ВЛИЯНИЕ ЭФФЕКТА ЧЕТЫРЕХВОЛНОВОГО СМЕШЕНИЯ НА КАЧЕСТВО ПЕРЕДАЧИ ОПТИЧЕСКИХ СИГНАЛОВ

Currently, almost everyone uses information transmission services. To meet all the needs, the power and data transmission rates in modern optical communication systems have reached enormous values. At high transmitted powers, undesirable nonlinear effects occur in the optical fiber, which reduce the efficiency of the entire optical system. Nonlinear effects in optical fibers impose various limitations on the communication channel, and understanding such effects is practically necessary. Four-wave mixing is the dominant nonlinear effect present in optical networks with wavelength-division multiplexing. The general provisions on the mechanism of manifestation of four-wave mixing in an optical fiber are substantiated. The article presents a variant of the classification of nonlinear effects. The types of four-wave mixing are considered. The paper shows the dependence of the FWM effect on the number of signals in the path and the phase ratio between the interacting signals. The authors propose ways to increase the reliability of optical signal transmission in fiber-optic transmission systems.

Adaptive Neuro-Fuzzy Inference System-based Nonlinear Equalizer for CO-OFDM Systems

Abstract The principle of orthogonal frequency-division multiplexing (OFDM) is to transmit the data through a large number of multiple orthogonal subcarriers. The coherent optical OFDM (CO-OFDM) is OFDM data that are being modulated to light frequency and being detected in coherent manner. CO-OFDM brings to optical communications the combination of two powerful techniques, coherent optical detection and OFDM. One of the primary challenges in the CO-OFDM system is to remove optical fiber nonlinear effects. This makes nonlinearity compensation a critical task of the CO-OFDM system. So a nonlinear equalizer (NLE) based on adaptive neuro-fuzzy inference system (ANFIS) is presented for CO-OFDM systems to mitigate nonlinearities on long-haul optical communications with high bit rate and bit error rate (BER)of the system. Various performance metrics were analyzed for the proposed ANFIS–NLE, and it is compared with existing techniques such as support vector machine and artificial neural network. From the experimental results, our proposed approach gives better performance in terms of BER and Q-factor on comparing with existing methods.

Аналіз особливостей застосування оптичних волокон у телекомунікаційній інфраструктурі залізничного транспорту

It is shown that it is advisable to use optical fibers as a physical medium for the information transmission in the construction of modern telecommunication systems and networks of railway transport. It is determined that multi-mode and single-mode optical fibers are used to create the physical medium of the telecommunication infrastructure of railway transport. The design and profiles of refractive indices of optical fibers are given. It is shown that the main parameters of optical fiber transmission are attenuation, dispersion (bandwidth) and nonlinear distortions. The main causes of optical signal attenuation are absorption of radiation by optical fiber material, Rayleigh scattering and radiation loss. It is determined that the dispersion of optical signals consists of inter-mode dispersion, chromatic dispersion and polarization mode dispersion. It is shown that nonlinear effects in optical fiber can be divided into scattering effects and effects related to changes in the refractive index depending on the radiation intensity. The influence of optical fiber transmission parameters on the quality of service provision in the railway telecommunication infrastructure has been analyzed. Transparency windows and spectral ranges for optical fibers used in various telecommunication technologies are considered. The classification of single-mode and multi-mode optical fibers according to ITU-T recommendations is presented. The features of each class of optical fibers are analyzed. The fields of application of optical fibers of different classes in the construction of modern telecommunication systems and networks of railway transport are presented.

Efficient femtosecond mid-infrared generation based on a Cr:ZnS oscillator and step-index fluoride fibers.

Femtosecond light sources in the 3-5μm region are highly sought after for numerous applications. While they can be generated by using nonlinear effects in optical fibers, the efficiencies and effectiveness of frequency conversion can be significantly enhanced by using ultrashort driving pulses. Here, we report on a few-cycle Cr:ZnS oscillator driving low-order soliton dynamics in soft-glass fibers. By selecting appropriate parameters, sub-two-cycle pulses or broad supercontinua spanning over 1.7 octaves from 1.6 to 5.1μm can be generated at average power levels exceeding 300mW. In the same setting, Raman-induced soliton self-frequency shifting has been exploited to generate sub-100-fs pulses continuously tunable from 2.3 to 3.85μm with a conversion efficiency of ∼50%. These results demonstrate the vast potential of using Cr:ZnS or Cr:ZnSe lasers for powerful mid-infrared generation.

Distributed Measurement of Fermi–Pasta–Ulam Recurrence in Optical Fibers

We experimentally demonstrate the distributed measurement of Fermi–Pasta–Ulam (FPU) recurrence in an optical fiber. Square-shaped pulses with weak modulation are injected into a single-mode fiber to exhibit FPU recurrence. Rayleigh backscattering signals of various sidebands are recorded to measure the power vibration along the optical fiber. The validity of the distributed method is confirmed both by the numerical simulation and the cutting-back method. Compared with the traditional cutting-back method, the distributed method has significant advantages, such as short measurement time, low cost, and good repeatability. We also believe that the distributed method has a great potential for the measurement of other nonlinear effects in optical fiber.

Enabling the study of photons orbital angular momentum for optical communications

The internet data traffic capacity is reaching the limits imposed by optical fiber nonlinear effects, having almost exhausted the available degrees of freedom needed to orthogonally multiplex data. Therefore, new methods should be developed to avoid the capacity crunch. The orbital angular momentum (OAM) of photons may be used as an additional degree of freedom. In this article, in order to enable the study of applications of OAM for optical communications, an experimental setup for modulation and demodulation of free space OAM carrying beams was conceived based on twsited nematic spatial light modulator technology. This work assesses the viability of this technology pointing that this low cost solution can enable the application of OAM for optical communications.

Review of Recent Progress in Digital Coherent Optical Communications

Abstracts: This paper reviews the recent progress in digital coherent optical communication technologies for core metro, and access transport network. Digital mitigations of various transmission impairment induced by Kerr -nonlinear effects in optical fibers are addressed.

All Regeneration for Optical Communication Network Using Optical 3R Regeneration and Phase Sensitive Amplifier

Nonlinear optical effects in fibers occur via ultrafast Kerr nonlinearity, offers a flexible framework within which numerous signal-processing functions can be accomplished. When high power launched in optical fiber, several nonlinear transmission impairment such as amplitude noise, phase noise, power spectral losses, that degrades the performance of optical communication system. All optical regeneration is one of the solution to mitigate transmission impairments instead of optical to electrical conversion. In this paper, all optical regeneration is demonstrated for 10Gb/s DPSK system using 3R regeneration and Phase sensitive amplification to mitigate amplitude and nonlinear phase noise form 10G noisy DPSK transmission system. Bit error rate of 10-11 is achieved at power penalty of 6 dB. The system is developed and tested using optisystem. The developed all optical regeneration system is very demanding for long distance transmission in high-speed communication systems.

Performance Analysis of Four Wave Mixing: A Non-Linear Effect in Optical fibers

Linear effects in Optical fibers are caused due to the refractive index of the optical medium's dependence on the intensity of light. One of the prominent non-linear effects in Optical fibers is the Four-wave mixing (FWM) phenomenon. FWM effect is resonant when the phase matching condition is satisfied. It only occurs for particular combinations of fiber dispersion and signal frequencies. The FWM is a very unpleasant transmission phenomenon occurring in a transparent optical network based on Dense Wave Division Multiplexing, but it could be used advantageously for implementing optical devices such as wavelength converters, parametric amplifiers, optical de-multiplexers, chromatic dispersion compensators, as well as signal to noise regenerators. This paper discusses the effect of channel spacing, laser power, and dispersion, length of the optical fiber and the variation of input power to compensate the effect of FWM when implemented in a short haul environment. General Terms

High gain pulsed erbium-doped fiber amplifier for the nonlinear characterization of SWCNTs photodeposited on optical fibers

We report the experimental setup of a high power pulsed erbium-doped fiber amplifier. An optical signal at 1550nm emitted by a distributed feedback laser is amplified by two identical stages in reflective configuration using one fiber Bragg grating at each one of those. We demonstrated that for pulses with a frequency of 20kHz and temporal duration of 10, 50, 100, and 500ns, it is possible to obtain output peak powers of 41, 22, 18, and 11W, respectively. We applied our high power amplifier in the characterization of nonlinear optical transmission of single-wall carbon nanotubes deposited on single mode optical fibers end-face by the photodeposition technique. Our results show that the high power system is ideal for carrying out studies of nonlinear effects in optical fibers as well as nonlinear characterization of nanostructured materials deposited on optical fibers.

Enhancement of Brillouin Scattering Signal in Perfluorinated Graded-Index Polymer Optical Fibers

Perfluorinated graded-index polymer optical fibers (PFGI-POFs), fabricated by replacing the hydrogen atoms of standard polymethyl methacrylate-based POFs with fluorine atoms, have been extensively studied due to their relatively low propagation loss even at telecommunication wavelength. Recently, Brillouin scattering, which is one of the most significant nonlinear effects in optical fibers, has been successfully observed in PFGI-POFs at 1.55-μm wavelength. The Brillouin Stokes signal was, however, not large enough for practical applications or for detailed investigations of the Brillouin properties. In this paper, we review our recent work on Stokes signal enhancement. First, we induce stimulated Brillouin scattering based on the so-called pump-probe technique, and discuss its applicability to temperature sensors. Then, we investigate the influence of the core diameter and length of PFGI-POFs on Stokes signal, and observe the Brillouin linewidth narrowing effect. We believe our work is an important technological step toward the implementation of practical Brillouin-based devices and systems including distributed strain and temperature sensors.

Methods for Estimation of Optical Fiber Non-Linearity Using Self-Phase Modulation Effect

Methods for Estimation of Optical Fiber Non-Linearity Using Self-Phase Modulation Effect Due to ever increasing channel density in WDM systems the nonlinear optical effects in fibers become a limiting factor for the high-speed data transmission, which necessitates determination of such important characteristic as the coefficient of optical nonlinearity. To measure it, two methods are proposed: continuous wave self-phase modulation (CW-SPM) and pulse phase self-modulation (P-SPM). The research work has been carried out both in the form of calculations and experimentally, taking as wavelength the central one from the third optical transparency window, λ = 1550 nm. Based on the OptSim 5.2 simulations and experimental results, the sought-for nonlinear coefficients have been calculated. In the paper, comparative analysis and estimation of the results are performed for two different optical fibers.

Mathematical modelling of nonlinear effects in optical fiber

Mathematical modelling of nonlinear effects in optical fiber

Highly Functional All-Optical Control Using Ultrafast Nonlinear Effects in Optical Fibers

Using the optical fibers and ultrashort pulses, we can demonstrate highly functional optical control. We have succeeded in generation of low-noise, ultraflat, high-quality supercontinuum (SC). Recently, octave spanning high-quality SC is also generated. The carrier envelope offset frequency measurement and ultrahigh resolution optical coherence tomography are demonstrated using SC. We can also generate widely wavelength-tunable ultrashort soliton pulses using soliton self-frequency shift (SSFS). So far, several new techniques have been proposed and demonstrated using SSFS. The author has also discovered novel two-pulse trapping phenomena. The ultrafast all-optical switching is demonstrated using the pulse trapping techniques, and principles and characteristics are described.