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Rare-earth ion doped oxide thin films integrated on silicon substrates provide a route toward scalable, chip-scale platforms for quantum coherent devices. Erbium-doped TiO 2 is an attractive candidate: the Er 3 + optical transition is compatible with C-band optical fiber communications, while TiO 2 is an insulating dielectric compatible with silicon process technology. Through structural and optical studies of Er-doped TiO 2 thin films grown via molecular beam deposition on silicon, SrTiO 3 , and sapphire substrates, we have explored the impact of polycrystallinity and microstructure on the optical properties of the Er emission. Comparing polycrystalline TiO 2 (rutile)/Si with single-crystalline TiO 2 (rutile)/r-sapphire and polycrystalline TiO 2 (anatase)/Si with single-crystalline TiO 2 (anatase)/ SrTiO 3 , we observe that the inhomogeneous linewidth (Γ inh) of the most prominent peak in the Er spectrum (the Y 1 – Z 1 transition, 1520 and 1533 nm in rutile and anatase TiO 2) is significantly narrower in the polycrystalline case. This implies a relative insensitivity to extended structural defects and grain boundaries in such films (as opposed to, e.g., point defects). We show that the growth of an undoped, underlying TiO 2 buffer on Si can reduce Γ inh by a factor of 4–5. Expectedly, Γ inh also reduces with decreasing Er concentrations: we observe a ∼ 2 order of magnitude reduction from ∼ 1000 ppm Er to ∼ 10 ppm Er. Γ inh then gets limited to a residual value of ∼ 5 GHz that is insensitive to further reduction in the Er concentration. Based upon the above results, we argue that the optical properties in these thin films are limited by the presence of high "grown-in" point defect concentrations. [ABSTRACT FROM AUTHOR]

The quantum well diode (QWD) performs a dual role, functioning both as an emitter and a detector due to its unique feature of spectral overlap between emission and detection spectra. This dual functionality positions QWDs as promising candidates in the realm of multifunctional sensors. Furthermore, the well-established maturity of optical fiber communication, grounded in its intrinsic property of total reflection, makes it an ideal transmission medium for QWD sensing signals. Leveraging the coexisting emission and detection capabilities of QWDs, we have constructed a sensing system in this article. This system utilizes a QWD, which is stimulated to emit light, with the emitted light traveling through a specified length of optical fiber. A specialized load-bearing film, featuring an aluminum membrane on its rear to act as a mirror and an object of known weight on its front, induces deformation in the film, thereby altering the characteristics of the reflected light. This modulated light is subsequently captured by the QWD via the optical fiber, enabling the computation of the weight of the object. In this article, the QWD's emission peak is around 522 nm, and its detection range extends from 370 to 530 nm. Furthermore, by employing the appropriate approach, integrating QWD with optical fibers can be extended to sensing and measuring various physical quantities such as temperature, solution concentration, wind speed, and more. The advantages of QWDs include cost-effectiveness, multifunctionality, portability, and environmental friendliness. This technology represents a promising avenue for sensor control in the era of the Internet of Things. [ABSTRACT FROM AUTHOR]

Near‐infrared II (NIR‐II, 900–1880 nm) fluorescence confocal microscopy offers high spatial resolution and extensive in vivo imaging capabilities. However, conventional confocal microscopy requires precise pinhole positioning, posing challenges due to the small size of the pinhole and invisible NIR‐II fluorescence. To simplify this, a fiber optical wavelength division multiplexer (WDM) replaces dichroic mirrors and traditional pinholes for excitation and fluorescence beams, allowing NIR‐IIb (1500–1700 nm) fluorescence and excitation light to be coupled into the same optical fiber. This streamlined system seamlessly integrates key components—excitation light, detector, and scanning microscopy—via optical fibers. Compared to traditional NIR‐II confocal systems, the fiber optical WDM configuration offers simplicity and ease of adjustment. Notably, this simplified system successfully achieves optical sectioning imaging of mouse cerebral blood vessels up to 1000 µm in depth. It can discern tiny blood vessels (diameter: 4.57 µm) at 800 µm depth with a signal‐to‐background ratio (SBR) of 5.34. Additionally, it clearly visualizes liver vessels, which are typically challenging to image, down to a depth of 300 µm. [ABSTRACT FROM AUTHOR]

The structural health of fiber-optic communication networks has become increasingly important due to their widespread deployment and reliance in interconnected cities. We demonstrate a smart upgrade of a communication system employing a dual-polarization-state polarization shift keying (2-PolSK) modulation format to enable distributed vibration monitoring. Sensing can be conducted without hardware changes or occupying additional communication bandwidth. Experimental results demonstrate that forward transmission-based distributed vibration sensing can coexist with PolSK data transmission without significant deterioration in performance. This proof-of-concept study achieved a sensitivity of 0.4141 μV/με with a limit of detection (LoD) of 563 pε/Hz1/2@100 Hz. The single-span sensing distance can reach up to 121 km (no optical amplification) with a positioning accuracy as small as 874 m. The transmission rate is 300 Mb/s, the QdB is 16.78 dB, and the corresponding BER is 5.202 × 10−12. For demonstration purposes, the tested vibration frequency range is between 100 and 200 Hz. [ABSTRACT FROM AUTHOR]

The emergence of higher-dimensional evolution equations in dissimilar scientific arenas has been on the rise recently with a vast concentration in optical fiber communications, shallow water waves, plasma physics, and fluid dynamics. Therefore, the present study deploys certain improved analytical methods to perform a solitonic analysis of the newly introduced three-dimensional nonlinear dynamical equations (all within the current year, 2024), which comprise the new (3 + 1) Kairat-II nonlinear equation, the latest (3 + 1) Kairat-X nonlinear equation, the new (3 + 1) Boussinesq type nonlinear equation, and the new (3 + 1) generalized nonlinear Korteweg–de Vries equation. Certainly, a solitonic analysis, or rather, the admittance of diverse solitonic solutions by these new models of interest, will greatly augment the findings at hand, which mainly deliberate on the satisfaction of the Painleve integrability property and the existence of solitonic structures using the classical Hirota method. Lastly, this study is relevant to contemporary research in many nonlinear scientific fields, like hyper-elasticity, material science, optical fibers, optics, and propagation of waves in nonlinear media, thereby unearthing several concealed features. [ABSTRACT FROM AUTHOR]

One of the most critical challenges in optical fiber communication systems using non-orthogonal multiple access (NOMA) techniques is reducing the peak-to-average power ratio (PAPR). Optical NOMA often leads to high PAPR, causing non-linear distortion and limiting the system's gain. The advanced Selected Mapping (SLM) algorithm is introduced in this work to reduce the PAPR of the O-NOMA. In conventional SLM, multiple phase sequences are applied to the input data, which requires numerous Inverse Fast Fourier Transform, increasing computational complexity. The proposed approach simplifies this by selecting a central reference phase sequence, reducing the number of candidate sequences and the number of IFFT operations required. This reduction in complexity does not significantly compromise the PAPR reduction capability, making the method more efficient. The SLM algorithm addresses this issue by applying the phase rotation factor to the transmitted signals, redistributing the power, and reducing the peak levels. This article highlights the benefits and challenges of implementing SLM in optical NOMA systems, including its compatibility with existing NOMA schemes. Matlab 2016 analyzes parameters such as bit error rate (BER), PAPR, and out-of-band radiation. A 66% PAPR reduction can be obtained using the suggested SLM with various phase variables. Furthermore, there is a −2650 reduction in spectrum leakage. The simulation outcomes of the work reveal the potential of SLM to reduce PAPR and enhance the BER and PSD performance of optical NOMA compared with the existing algorithms. [ABSTRACT FROM AUTHOR]

This article analyzes and examines the nonlinear Maccari's equations with a noise term using the powerful sub-equation mathematical approach. Several significant solitary and rational solutions have been provided. These solutions are crucial in a number of fields, such as superfluid, optical fiber communication, and space-confined plasma waves. The effects of model parameters on the obtained solutions' features have been discussed. The randomness parameter affects the envelope, solitonic structures, and energy properties. It was reported that by increasing the random parameter, Brownian isolated driving shock waves with random amplitude were produced. Finally, the method described here may be applied to many nonlinear systems and new energy trends in natural science. [ABSTRACT FROM AUTHOR]

Digital twin (DT) modeling is essential to optical fiber communication systems, particularly for enhancing system performance, controlling the system in real time, and understanding signal nonlinearity. Conventional split‐step Fourier method ‐based simulations, however, struggle with wide‐band transmissions, plagued by increasing complexity and inherent biases due to inconsistent link parameter availability. Addressing these challenges, a hybrid data‐driven and model‐driven DT approach for the wide‐band and long‐haul physical systems with various system effects is developed. The approach utilizes a neural network (NN) to capture fiber nonlinear features as well as biased perturbations as "lumped" stochastic noises while offloading the linear effects to modules described by physical models of link elements. The model, tested in a 30.5‐Tbps 1200 km fiber transmission link with 40 channels, achieves a mean Q factor error of less than 0.1 dB and a maximum runtime of 1.3 s for NN processing under various launch powers, transmission lengths, and optical signal‐to‐noise ratios. Furthermore, the study has implemented a nonlinear compensation algorithm on the DT model, yielding a consistent enhancement in experimental data. The accuracy and adaptability of the DT model underline its suitability for planning, design, and optimization within the physical optical fiber communication systems. [ABSTRACT FROM AUTHOR]

This study investigates the dynamics of boomerang solitons and their interactions in three-mode fiber under the influence of inhomogeneous effects governed by three-coupled nonlinear Schrödinger (3-CNLS) equations in GVD and nonlinearity coefficients. Also, 3-CNLS equation can be used to investigate the optical soliton propagation in three-core fibers, which contain some potential applications in the optical fiber communication system. Using the Darboux transformation method with computer simulation, the two-bright boomerang soliton solutions are attained analytically for the dispersion and nonlinearity functions. The propagation and interaction properties of boomerang solitons are investigated, while the variable coefficients are adopted as linear functions. Various interaction scenarios are illustrated by plotted figures to reveal the importance of obtained soliton solutions. The physical significance of boomerang solitons can be understood from the displayed figures. The obtained results will be benefit soliton path control and soliton phase management in an inhomogeneous three-core optical fiber. [ABSTRACT FROM AUTHOR]

Non-Kerr media, twin-core nonlinear optical fibers and waveguides are widely applied in optical fiber communications. In order to model the effects of quintic nonlinearity for the ultrashort optical pulse propagation in a non-Kerr medium, twin-core nonlinear optical fiber or waveguide, a coupled variable-coefficient cubic-quintic nonlinear Schrödinger system is investigated in this paper. For the two components of the electromagnetic fields, on the basis of the existing Lax pair, we take a gauge transformation to convert a Lax pair into an Ablowitz-Kaup-Newell-Segur system. Then we acquire a system, which is equal to the original system. The N-fold Darboux transformation is derived based on our Lax pair, where N is a positive integer. Applying Taylor series, we derive the N-fold generalized Darboux transformation. The second- and third-order vector breather solutions are obtained via the generalized Darboux transformation method. All our results depend on the variable coefficients of the original system. Our results might be of some use in a non-Kerr medium, twin-core nonlinear optical fiber or waveguide system. [ABSTRACT FROM AUTHOR]

In long-haul WDM (wavelength division multiplexing) optical communication systems utilizing the DP-16QAM modulation scheme, traditional methods for removing chaos have exhibited poor performance, resulting in a high bit error rate of 10 − 2 between the original signal and the removed chaos signal. To address this issue, we propose DeepChaos+, a machine learning-based approach for chaos removal in WDM transmission systems. Our framework comprises two key points: (1) DeepChaos+ automatically generates a dataset that accurately reflects the features of the original signals in the communication system, which eliminates the need for time-consuming data simulation, streamlining the process significantly; (2) it allows for the training of a lightweight model that provides fast prediction times while maintaining high accuracy. This allows for both efficient and reliable signal reconstruction. Through extensive experiments, we demonstrate that DeepChaos+ achieves accurate reconstruction of the original signal with a significantly reduced bit error rate of approximately 10 − 5 . Additionally, DeepChaos+ exhibits high efficiency in terms of processing time, facilitating fast and reliable signal reconstruction. Our results underscore the effectiveness of DeepChaos+ in removing chaos from WDM transmission systems. By enhancing the reliability and efficiency of chaotic secure channels in optical fiber communication systems, DeepChaos+ holds the potential to improve data transmission in high-speed networks. [ABSTRACT FROM AUTHOR]

A method is developed to make an optical fiber that only transmits fully linearly polarized light and maintains the polarization state. The method for efficient ingesting laser into this fiber is also reported. Using an optical fiber with a prism head, we can compress a plane wave into the thin rectangular cross-section fiber, and the light intensity within the fiber is much larger than that of the incidence wave. Our finite-difference time-domain (FDTD) simulation results show that the compressed light in the fiber becomes fully polarized and maintains the polarization state, and can be well coupled out by the resonance rings. This method is suitable for developing highly efficient polarization-maintaining optical fibers in a much simpler way, for applications in photonic integrated circuits or optical sensors. [ABSTRACT FROM AUTHOR]

Passive Optical Networks (PONs) are telecommunication technologies that use fiber-optic cables to deliver high-speed internet and other communication services to end users. PONs split optical signals from a single fiber into multiple fibers, serving multiple homes or businesses without requiring active electronic components. PONs planning involves designing and optimizing the infrastructure for delivering fiber-optic communications to end users. The main contribution of this paper is the introduction of tailored operators within a genetic algorithm (GA) optimization approach for PONs planning. A three vector and an aggregator vector are devised to account, respectively, for physical and logical connections of the network, facilitating the execution of GA operators. This codification and these operators are versatile and can be applied to any population-based algorithm, not limited to GAs alone. Furthermore, the proposed operators are specifically designed to exploit the unique characteristics of PONs, thereby minimizing the occurrence of unfeasible solutions and accelerating convergence towards an optimal network design. By incorporating these specialized operators, this research aims to enhance the efficiency of PONs planning, ultimately leading to reduced costs and improved network performance. [ABSTRACT FROM AUTHOR]

Photonic crystal fiber is a category of optical fibers, getting great attention by its promise to offer a range of optical characteristics that are not achievable in conventional optical fibers. Engineered dispersion and nonlinear characteristics of photonic crystal fiber (PCF) make it an attractive candidate for nonlinear optics and advanced optical networking in the all-optical domain. An optical network consists of different optical components such as laser sources, amplifiers, regenerators, and convertors for proper signal transmission over long distances. In recent years, the performance of the components has been improving by employing the appealing properties of PCF. The PCF's application on such components is discussed, and the simulated results on gain amplification, regeneration, conversion, fiber laser are reviewed. These developments reveal that the enhanced performance provided by PCF makes it suitable for different optics applications. [ABSTRACT FROM AUTHOR]

In this study, the nonlinear two-dimensional Kadomtsev–Petviashvili-modified equal width (KP-MEW) equation is under investigation, which is described as a nonlinear wave model in weakly restoring forces and shallow water waves in the way of ferromagnetic, solitary waves in two dimensions with short amplitude and long wavelength and are also helpful in the investigation of various behaviors in nonlinear sciences. We successfully found the interesting and novel solitary wave results in bright solitons, kink solitons, dark solitons, anti-kink solitons, periodic singular solitons for nonlinear two-dimensional KP-MEW equation on the base of extension of simple equation technique under symbolic computational software Mathematica. The created solitons play an important role in nonlinear engineering and physics such as nonlinear optics, nonlinear dynamics, soliton wave theory, optical fiber and communication system. We are sure that these constructed results are novel and interesting which does not exist in the previous literature works. The graphical representation of constructed results is shown by 2D, 3D and contour graphs. The investigated research work proved that utilized technique is more concise, straightaway and efficient for study of other nonlinear partial differential equations. [ABSTRACT FROM AUTHOR]

The mode coupling in a graded-index polymer photonic crystal fiber (GI PPCF) with a solid core has been investigated using the Langevin equation. Based on the computer-simulated Langevin force, the Langevin equation is numerically integrated. The numerical solutions of the Langevin equation align with those of the time-independent power flow equation (TI PFE). We showed that by solving the Langevin equation, which is a stochastic differential equation, one can successfully treat a mode coupling in GI PPCFs, which is an intrinsically stochastic process. We demonstrated that, in terms of effectiveness, the Langevin equation is preferable compared to the TI PFE. The GI PPCF achieves the equilibrium mode distribution (EMD) at a coupling length that is even shorter than the conventional GI plastic optical fiber (POF). The application of multimode GI PCFs in communications and optical fiber sensor systems will benefit from these findings. [ABSTRACT FROM AUTHOR]

In fiber-optic communication systems, it is crucial for operators to accurately monitor various physical parameters along optical links to fully leverage the potential transmission capacity and conduct fault analysis. Digital longitudinal monitoring (DLM) has been intensively studied for its capability of monitoring various physical parameters, such as optical power, distributed along the fiber-longitudinal direction by solely processing signals received at coherent receivers. In this article, the fundamentals and recent advances in DLM are reviewed, including working principles, spatial resolution, and key experiments demonstrating its feasibility for use in operations. [ABSTRACT FROM AUTHOR]

In a world increasingly and unevenly connected through fiber-optic cables, satellite waves, and smartphones, spatial approaches attentive to questions of power and scale are key to grounding analysis of digital networks and illuminating the possibilities and instabilities created through network linkages. This article examines digital networks of democratic mobilization through the analytical lenses of poststructuralist, new materialist, and feminist and decolonial approaches. By developing a heuristic of performative, material, and rooted approaches to network analysis, this article exposes the underlying theoretical presuppositions and analytical possibilities enabled by different ways of thinking with and through networks in geography. Performative approaches advance an understanding of networks as dynamic, dispersed assemblages, providing a theoretical lens that accounts for fluidity and multicausality. Material approaches call attention to the concrete backbones of digital infrastructures, highlighting the pathways and chokepoints that enable and constrain multiscalar flows of information. Rooted approaches foreground the spatial dimensions of social embeddedness, illuminating how digital networks emerge from and are constrained by longer struggles over territory and place making. Through empirical engagement with the networked mobilizations of the Arab Spring and the Milk Tea Alliance, we bring the insights of geographic scholarship to bear on emerging work on digital social networks and show how historically rooted spatial relations condition new vectors of risk and crisis. By tracing the ontological and epistemological orientations of particular strands of performative, new materialist, and rooted approaches, we recenter scale, territory, and place making, while emphasizing the political nature of network analysis across today's digital landscapes. [ABSTRACT FROM AUTHOR]

The deep integration of communication and sensing technology in fiber-optic systems has been highly sought after in recent years, with the aim of rapid and cost-effective large-scale upgrading of existing communication cables in order to monitor ocean activities. As a proof-of-concept demonstration, a high-degree of compatibility was shown between forward-transmission distributed fiber-optic vibration sensing and an on–off keying (OOK)-based communication system. This type of deep integration allows distributed sensing to utilize the optical fiber communication cable, wavelength channel, optical signal and demodulation receiver. The addition of distributed sensing functionality does not have an impact on the communication performance, as sensing involves no hardware changes and does not occupy any bandwidth; instead, it non-intrusively analyzes inherent vibration-induced noise in the data transmitted. Likewise, the transmission of communication data does not affect the sensing performance. For data transmission, 150 Mb/s was demonstrated with a BER of 2.8 × 10−7 and a QdB of 14.1. For vibration sensing, the forward-transmission method offers distance, time, frequency, intensity and phase-resolved monitoring. The limit of detection (LoD) is 8.3 pε/Hz1/2 at 1 kHz. The single-span sensing distance is 101.3 km (no optical amplification), with a spatial resolution of 0.08 m, and positioning accuracy can be as low as 10.1 m. No data averaging was performed during signal processing. The vibration frequency range tested is 10–1000 Hz. [ABSTRACT FROM AUTHOR]

The recent and tremendous rise in the number of mobile users demands a parallel increase in the capacity of wireless networks required to achieve higher data rates, lower latency transmissions, and improved service quality. The latter is influenced highly by frequent interruption of wireless service for users at the edge of the cell due to the longer distance from the base station. To overcome this problem and in the meantime improve the capacity of the bottleneck backhaul in dense heterogeneous networks like 5G/6G systems especially in the cell edge regions, a hybrid solution that combines Radio Frequency (RF), Free Space Optics (FSO), and Optical Fiber (OF) links for backhaul transmission is proposed in this paper. In addition, a Backhaul Selection Algorithm (BSA) is suggested to choose the optimum link according to the outage probability analyses. This algorithm not only selects the link with the highest quality but also minimizing power consumption, thereby guaranteeing a consistently high-quality connection without interruptions of services. Using theoretical analyses and thorough simulations, the performance of the hybrid RF/FSOOF system is evaluated and also compared to the existing state-of-the-art techniques showing the advantages of exploiting the inherited synergies of the proposal along with the selection algorithm. The numerical results reveal that the proposed system brings a considerable reduction in power consumption compared to FSO- and RF-only systems reflecting its superiority under different atmospheric channel conditions. For instance, at SNR threshold of 10 dB, the proposed system required SNR of 20, 25 and 33 dB, respectively, for weak, moderate, and strong atmospheric turbulence conditions in order to reach the outage probability of 10-6. [ABSTRACT FROM AUTHOR]

Researchers worldwide have shown significant interest in doping glasses with rare-earth ions. This is particularly intriguing because rare-earth ions are extensively used to enhance the optical properties of host glasses, capitalizing on their unique spectroscopic characteristics due to optical transitions within the intra-4f shell. An in-depth review was conducted on various glass fabrication methods, such as sputtering, solgel, chemical vapor deposition, ion exchange, and direct melt quenching. The study emphasized the physical, optical, and photoluminescence properties of glasses made from glass formers co-doped with rareearth ions. Understanding the interrelationship between these properties is crucial for optimizing material performance across various technological applications. The research highlights the broad applicability of rare-earth-doped glasses in fields like white light emission, photonic devices, solid-state lasers, optical fiber communication, and biomedical applications. [ABSTRACT FROM AUTHOR]

【Objective】With the continuous emergence of information-based bandwidth-consuming services such as 5th Generation Mobile Communication Technology (5G), the Internet of Things, and cloud computing, people’s demand for high-speed information transmission has increased dramatically. However, due to the inherent nonlinear effects, the transmission capacity of single-mode optical fiber has approached the Shannon limit, and it will no longer be able to meet people’s needs for ultra-high-speed and large-capacity transmission. Solving the transmission capacity problem has become a top priority. In order to solve the needs of large-capacity communication systems and long-distance high-speed transmission problems, we have built a two-mode single-channel C-band Few Mode Fiber (FMF) transmission system.【Methods】At the transmitting end, an arbitrary waveform generator is used to convert the digital signal into an electrical signal and drive the In-phase and Quadrature (IQ) modulator to modulate the optical carrier. The modulated signal is transmitted simultaneously using two multiplexing technologies: Mode Division Multiplexing (MDM) and Polarization Division Multiplexing (PDM). In order to achieve long-distance transmission of dual-mode signals of 1 000 km, we construct a dual-circulation loop system. Each time the signal passes through the loop, it will pass through a 50 km FMF. After being transmitted to the target distance, the coupler outputs the signal to the demultiplexing module, and the coherent optical receiver performs homodyne detection on the demultiplexed modulated signal. Finally, the transmitted signal is stored in an oscilloscope for offline Digital Signal Processing (DSP). The signal is sequentially subjected to frequency domain dispersion compensation, downsampling, clock recovery, and least mean square algorithm to restore the original signal.【Results】It was found that within the range of Optical Signal-to-Noise Ratio (OSNR) of each channel in the experiment, the Bit Error Rate (BER) under low Signal to Noise Ratio (SNR) is close to the theoretical channel result. Under high SNR condition, the BER is 1×10-2, which is 2.5 dB away from the theoretical value. We test the BER of LP11a and LP11b modes at Back-To-Back (BTB) and 250, 500, 750 and 1 000 km transmission cases respectively. The BER at all distances are lower than the Low-Density Parity-Check (LDPC) soft decision threshold with 28% redundancy (5.2×10-2 Soft Decision - Forward Error Correction (SD-FEC)). The BER after 1 000 km transmission in the two modes are 1.7×10-2 and 1.8×10-2 respectively, and the total net transmission rate is 400 Gbit/s.【Conclusion】This article demonstrates the transmission of a 32 Gbaud MDM-PDM-16 Quadrature Amplitude Modulation (QAM) C-band signal in a 1 000 km two-mode single-channel FMF system. At the receiving end, the advanced Multiple Input Multiple Output (MIMO)-DSP algorithm is used for channel equalization, and the obtained two-mode BER of 1.7×10-2 and 1.8×10-2 are both lower than the LDPC SD-FEC threshold with 28% redundancy. The result reachs a domestic record of 400 Gbit/s net transmission rate based on FMF transmission, and highlight the potential of FMF in large-capacity long-distance transmission.

To address the high-cost issue of twin single sideband quadrature phase shift keying (Twin-SSB-QPSK) signals in optical transmission, a optical fiber communication system was proposed, in which a single photodetector (PD) was employed at the receiver to directly detect the Twin-SSB-QPSK signals. At the receiver end, optical bandpass filter (OBPF) was not required to separate the two optical single sideband signals of the Twin-SSB-QPSK signal. Instead, the heterodyne effect of direct detection was utilized, allowing a single PD to directly detect the coherent superposition of the twin two optical single sideband QPSK signals, resulting in a single 16-ary quadrature amplitude modulation (16QAM) signal. Simulations demonstrated that two 56 Gbit/s QPSK signals were combined into a single 112 Gbit/s 16QAM signal and then compared with the traditional single 16QAM signal transmission scheme. The simulation results indicate that the proposed scheme does not introduce additional power penalties while reducing the system device requirements and deployment costs.

The stochastic generalized nonlinear Schrödinger equation (SGNLSE) of third order in the Stratonovich sense is examined here. New elliptic, hyperbolic, trigonometric, and rational stochastic solutions are obtained using a modified mapping method. Because the GNLSE is extensively used in nonlinear optical phenomena, optical fiber communication systems, communication and heat pulse propagation in materials, the obtained solutions may be used to study a broad range of relevant physical phenomena. In order to interpret the effects of multiplicative noise, the dynamic performances of the various obtained solutions are displayed utilizing 3-D and 2-D graphs. We infer that multiplicative noise impacts and stabilizes the behavior of SGNLSE solutions. [ABSTRACT FROM AUTHOR]

This paper leverages the Ginzburg–Landau equation, a fundamental model for elucidating the dynamics of dissipative optical solitons, in conjunction with the Markov Chain Monte Carlo method and the Lilliefors normality test, to precisely identify key parameters such as dispersion coefficient, nonlinear coefficient, and gain coefficient. Our comprehensive analysis yields not only posterior mean estimates and confidence intervals for these parameters but also their corresponding posterior probability density functions. These findings offer valuable statistical insights and theoretical underpinnings for the design and optimization of fiber lasers, with implications for enhancing the performance of fiber-optic communication systems. [ABSTRACT FROM AUTHOR]

This research explored optical soliton solutions for the (2+1)-dimensional generalized fractional Kundu-Mukherjee-Naskar equation (gFKMNE), which is a nonlinear model for explaining pulse transmission in communication structures and optical fibers. Two enhanced variants of (G'/G)- expansion method were employed, namely, extended (G'/G)-expansion method and the generalized (r + G'/G)-expansion method, based on the wave transformation of the model into integer-order nonlinear ordinary differential equations (NODEs). By assuming a series-form solution for the resultant NODEs, these strategic methods further translated them into a system of nonlinear algebraic equations. Solving these equations provided optical soliton solutions for gFKMNE using the Maple-13 tool. Through 3D and contour visuals, it was revealed that the constructed soliton solutions are periodically arranged in the optical medium, forming dark soliton lattices. These dark soliton lattices are significant in several domains, such as optical signal processing, optical communications, and nonlinear optics. [ABSTRACT FROM AUTHOR]

In this research article, we demonstrate the generalized expansion method to investigate nonlinear integro-partial differential equations via an efficient mathematical method for generating abundant exact solutions for two types of applicable nonlinear models. Moreover, stability analysis and modulation instability are also studied for two types of nonlinear models in this present investigation. These analyses have several applications including analyzing control systems, engineering, biomedical engineering, neural networks, optical fiber communications, signal processing, nonlinear imaging techniques, oceanography, and astrophysical phenomena. To study nonlinear PDEs analytically, exact traveling wave solutions are in high demand. In this paper, the (1 + 1)-dimensional integro-differential Ito equation (IDIE), relevant in various branches of physics, statistical mechanics, condensed matter physics, quantum field theory, the dynamics of complex systems, etc., and also the (2 + 1)-dimensional integro-differential Sawda–Kotera equation (IDSKE), providing insights into the several physical fields, especially quantum gravity field theory, conformal field theory, neural networks, signal processing, control systems, etc., are investigated to obtain a variety of wave solutions in modern physics by using the mentioned method. Since abundant exact wave solutions give us vast information about the physical phenomena of the mentioned models, our analysis aims to determine various types of traveling wave solutions via a different integrable ordinary differential equation. Furthermore, the characteristics of the obtained new exact solutions have been illustrated by some figures. The method used here is candid, convenient, proficient, and overwhelming compared to other existing computational techniques in solving other current world physical problems. This article provides an exemplary practice of finding new types of analytical equations. [ABSTRACT FROM AUTHOR]

The transformation regulation of the radial finite Airy-Gaussian beam array (FAiGBA) in uniaxial crystals orthogonal to the optical axis has been explored analytically and numerically under the paraxial approximation. The analytical evolution solution of this beam array in the x- and y-directions has been derived, respectively. The intensity distribution and side view of FAiGBA propagating in three types of uniaxial crystals have been demonstrated in several instances. Furthermore, particular attention has been devoted to the linear effect when this beam array transmits through the electro-optic crystal. The influence of non-paraxial longitudinal component and temperature on FAiGBA evolution characteristics has also been examined to verify the validity of the paraxial mechanism of this beam array propagating in uniaxial crystals. It is anticipated that these research findings will contribute to the advancement of FAiGBA applications in micro- and nano-control, optical fiber communication, optical trapping, and manipulation fields. [ABSTRACT FROM AUTHOR]

Novel method of nonlinear interchannel distortions generation in coherent multichannel fiber-optic transmission was proposed. Series of experiments was made to measure nonlinear interference noise in links with distributed amplification by co-propagating Raman pump. Based on the measurement results, a correction term to known GN-model formulas for calculating the power of nonlinear interference noise was proposed. Proposed formula demonstrate acceptable accuracy. [ABSTRACT FROM AUTHOR]

We present a novel photon-acid diffusion method to integrate polymer microlenses (MLs) on a four-channel, high-speed photo-receiver consisting of normal-incidence germanium (Ge) p-i-n photodiodes (PDs) fabricated on a 200 mm Si substrate. For a 29 µm diameter PD capped with a 54 µm diameter ML, its dark current, responsivity, 3 dB bandwidth (BW), and effective aperture size at −3 V bias and 850 nm wavelength are measured to be 138 nA, 0.6 A/W, 21.4 GHz, and 54 µm, respectively. The enlarged aperture size significantly decouples the tradeoff between aperture size and BW and enhances the optical fiber misalignment tolerance from ±5 µm to ±15 µm to ease the module packaging precision. The sensitivity of the photo-receiver is measured to be −9.2 dBm at 25.78 Gb/s with a bit error rate of 10−12 using non-return-to-zero (NRZ) transmission. Reliability tests are performed, and the results show that the fabricated Ge PDs integrated with polymer MLs pass the GR-468 reliability assurance standard. The demonstrated photo-receiver, a first of its kind to the best of our knowledge, features decent performance, high yield, high throughput, low cost, and compatibility with complementary metal-oxide-semiconductor (CMOS) fabrication processes, and may be further applied to 400 Gb/s pulse-amplitude modulation four-level (PAM4) communication. [ABSTRACT FROM AUTHOR]

Random fiber lasers (RFLs), a new variety of random lasers, have become a vigorous research spot over the past decades. RFLs possess superiorities in efficiency, structural flexibility, directionality, cost, etc. Particularly, RFLs are discovered to be good platforms for the construction of various forms of high‐performance lasers. Herein, recent progress in the spectral manipulation of RFLs and the applications of spectral‐tailored RFLs are reviewed. Both theoretical and experimental investigations of the unique spectral properties of RFLs up to now are presented. The superior wavelength flexibility of RFLs which can achieve any desired lasing wavelength in the 1–2.1 µm band is highlighted. Via spectral manipulation, RFLs have shown the capability of high‐spectral‐purity, narrow‐bandwidth, and multi‐wavelength output. Furthermore, the RFLs featuring unique spectral properties can lead to various promising applications, which are concisely summarized, including optical fiber communication, optical fiber sensing, imaging, supercontinuum generation, nonlinear‐frequency conversion, mid‐infrared lasing pump sources, and laser‐driven inertial confinement fusion motivation. The challenges and prospects for RFLs are also discussed. [ABSTRACT FROM AUTHOR]

Midinfrared photonic devices are used as lasers and photodetectors in optical gas sensors and fiber‐optic communications. Herein, the pair number dependence and strain compensation dependence of the InAsSb/InAsP superlattice structure to increase luminescence intensity and reduce crystal defects is investigated. InAs substrates are used to demonstrate various effects of strain compensation, including its role in increasing luminescence intensity and improving the surface flatness. Furthermore, the photoluminescence spectra of a grown superlattice between the InAs substrate and GaAs substrate with two‐temperature‐step growth are shown. [ABSTRACT FROM AUTHOR]

Optical fiber interconnects are playing a vital role in satisfying the demand for high-speed data transmission for long-range applications. The primary goal of the work presented here is to design an optical fiber communications system suitable for use at distances of up to 100 km. In this work, an intensity-modulated scheme at the transmitter and direct reception at the detector are employed to lower the overall system cost. Single-mode fiber (SMF) with nonlinearities is used as a transmission medium, connecting both transmitting and receiving sections. In order to get rid of the distortion brought on by the fiber, Bragg grating is used at the SMF's output. A Gaussian LPF is included in the receiver to eliminate the APD noise induced in the process of optical-to-electrical signal conversion. The performance of the system at 10 Gbps is assessed by examining the BER, Q-factor, and eye diagrams. The theoretical description of a Bragg grating is provided, and this work employs Optisystem softwarebased simulation. The results obtained reveal a BER value below 10-13 in the entire range of 100 km, in addition to the eye-opening factor of 0.85. [ABSTRACT FROM AUTHOR]

This manuscript elaborate a novel characteristic of stochastic multi breather type, periodic, hybrid periodic and different type of waves solutions for the Shrödinger–Hirota (SH) equation. The mentioned equation is studied by a Wiener process and white noise which is used for the sudden and large-scale fluctuation. By applying the wave transformation technique the considered equation is transformed into ordinary differential equations, gives meaningful analysis. From the solution of the SH equation various type of results, including breather like waves, hybrid periodic waves, and singular solitons. Breather waves are applied in optical fiber communications, oceanography, and plasma physics. Singular waves find use in medical imaging, seismic research, and nonlinear optics. Hybrid singular-periodic waves have applications in photonics, acoustics, and material science, enabling advancements in diverse fields. To visually capture these intricate behaviors, we used Mathematica software to generate 2D and 3D graphs of the analytical stochastic solutions. This combination of mathematical rigor and numerical simulations provides a comprehensive understanding of the phenomena under study, making a valuable contribution to the field of nonlinear wave equations and stochastic processes. [ABSTRACT FROM AUTHOR]

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Precise control of dispersion output holds paramount significance across domains such as optical fiber communication, time stretching, and spectral interferometric ranging. In comparison to other dispersion elements, like prisms, gratings are widely applied in the field of dispersion control due to their advantages of broad spectral range, tunability, and high resolution. Moreover, linear dispersion is the most desired characteristic by designers in most cases. Here, we develop a dispersion model for grating groups to determine the optimal structural parameters for achieving linear dispersion in high-order grating arrays. Based on our model, we provide corresponding parameter selection methods that allow for quantitative design of the size and slope of output dispersion by adjusting input parameters such as angle, distance, and parallelism. Additionally, we experimentally establish a dispersion interferometry structure based on the grating ensemble that validates our proposed approach's capability for linear dispersion output (linearity better than 0.9998). We believe that our approach is universally significant and contributes to enhancing the performance of dispersion interferometric measurement systems, chirp amplification systems, and other related systems. [ABSTRACT FROM AUTHOR]

The concern of this study is to investigate the optical solitons pluses. The (2 + 1) -dimensional Kundu–Mukherjee–Naskar (KMN) mathematical model in birefringent fibers is taken under consideration for this sake because this model has great importance in optics and delineate the propagation of soliton dynamics in optical fiber communication system and the rogue waves in the oceans and the bending of the light beam. Two newly developed approaches first extended rational sinh-Gordon method which is formulated from the well-known sinh-Gordon equation and second exp (− ϕ (ϖ)) -expansion function method are manipulated for the construction of optical solitons in distinct formats. Bright, dark, and singular along their combined forms, periodic and plane wave solutions are extracted with the aid of proposed methods. Moreover, the modulation instability of investigated model is also carried out via linear stability theory. To endorse the physical compatibility of the results, the 2D, 3D, contour, and density plots have been delineated using appropriate parametric values. According to our literature research, these two methods that we are working on have not been applied to the KMN equation in birefringent fibers before, and we believe that the new solutions we have obtained will be useful to researchers working in modeling in this field. The evaluated results suggested that the techniques employed in this research to recover inclusive and standard solutions are approachable, efficient, and speedier in computing and can be considered a handy tool in solving more complex phenomena with the assistance of symbolic computation. [ABSTRACT FROM AUTHOR]

An essential mathematical structure that demonstrates the nonlinear short-wave movement across the ferromagnetic materials having zero conductivity in an exterior region is known as the fractional stochastic Kraenkel–Manna–Merle system. In this article, we extract abundant wave structure closed-form soliton solutions to the fractional stochastic Kraenkel–Manna–Merle system with some important analyses, such as bifurcation analysis, chaotic behaviors, sensitivity, and modulation instability. This fractional system renders a substantial impact on signal transmission, information systems, control theory, condensed matter physics, dynamics of chemical reactions, optical fiber communication, electromagnetism, image analysis, species coexistence, speech recognition, financial market behavior, etc. The Sardar sub-equation approach was implemented to generate several genuine innovative closed-form soliton solutions. Additionally, phase portraiture of bifurcation analysis, chaotic behaviors, sensitivity, and modulation instability were employed to monitor the qualitative characteristics of the dynamical system. A certain number of the accumulated outcomes were graphed, including singular shape, kink-shaped, soliton-shaped, and dark kink-shaped soliton in terms of 3D and contour plots to better understand the physical mechanisms of fractional system. The results show that the proposed methodology with analysis in comparison with the other methods is very structured, simple, and extremely successful in analyzing the behavior of nonlinear evolution equations in the field of fractional PDEs. Assessments from this study can be utilized to provide theoretical advice for improving the fidelity and efficiency of soliton dissemination. [ABSTRACT FROM AUTHOR]

This work focuses on the study of the paraxial wave model with a space–time fractional form. This model has more importance for describing light propagation in nonlinear optical fibers and telecommunication lines. The main aim of this work is to observe the effect of the fractional parameters and compare the truncated M -fraction with the beta-fraction, conformable fraction form, and classical form of the PW model. For this observation, we applied the Simplest equation technique to acquire analytical solutions to the space–time (spatiotemporal) M -fractional paraxial wave model. We are able to acquire several new optical soliton solutions, including periodic waves, kink-type waves, rogue-type waves, and several novel periodic waves, by providing the appropriate fractional parametric values. These solutions have significance for shedding light on a number of physical phenomena in the realms of optical fiber and communication sciences. The diverse values of fractional parameters and the three-dimensional and contour plot graphs of certain chosen solutions are depicted, which are the most accurate physical characterizations of the outcomes. We also sketch the comparative graph of diverse fractional forms and the classical form of the paraxial wave equation in two-dimensional plots. Consequently, our findings represent an important breakthrough in this complex area and help further develop our comprehension of the behavior of solitons. [ABSTRACT FROM AUTHOR]

This work simulates the (1+1)-dimensional nonlinear perturbed Schrödinger model (NLPSM ). Hydrodynamics, elastic media, nonlinear optical fiber communication, and plasma physics are just a few of this model's mathematical physics and engineering applications. The study aims to accomplish two main objectives. First, it seeks to find unique soliton solutions such as solitary, dark, periodic, and plane wave solutions that haven't been found in the literature before using the modified Sardar sub-equation approach (MSSEA ). Second, a novel approach to analysis called bifurcation analysis is used to investigate the dynamic behavior of the model. Physical compatibility findings are supported by density, 3-D, and 2-D illustrations made with parametric variables. The analysis shows that the approach used to quickly acquire complete and typical answers was successful. This approach works well for solving challenging problems in physics, engineering, mathematics and fiber optic phenomena. [ABSTRACT FROM AUTHOR]

The Quantum Noise Stream Cipher (QNSC) is offering very high security in physical layer of optical fiber communication network to meet the today's main requirement of secure networks. However, the problem of timing and carrier frequency offset synchronization was higher for Coherent optical orthogonal Frequency Division Multiplexing (CO-OFDM) systems using QNSC for network security. For higher-order modulation systems, the algorithms used to overcome this problem are offering very low accuracy. In addition to this, the chances of attack by an illegal receiver are more due to no encryption used for the preamble creation. Existing algorithms used to create a new preamble is: CNI ((conjugate, negative, and image) with Pseudo-Noise sequence) and CNC ((conjugate and negative) with Chu sequence). In this paper, ConvNN (Convolutional Neural Network) and CapNN (Capsule Neural Network) based joint synchronization of timing and frequency for CO-OFDM system is proposed. From the experiments, performed at 10Gbps, it has been illustrated that the proposed networks are giving more robust results. In addition to these proposed networks are offering better and secure performance for both timing and frequency offset synchronization by using less training data. [ABSTRACT FROM AUTHOR]

This study explores optical soliton solutions within the framework of the Caudrey–Dodd–Gibbon equation (CDGE) and the ( 1 + 1 )-dimensional Boussinesq equation, utilizing the modified Sardar sub-equation method (MSSEM). The derived solutions are meticulously verified using symbolic software Mathematica and encompass a rich array of mathematical functions, including trigonometric, hyperbolic, and exponential functions. Visualization techniques, such as 3D plots, 2D plots, density graphs, and contour graphs, effectively illustrate the diverse behaviors exhibited by these soliton solutions. These equations have been studied previously, their comprehensive traveling wave solutions are relatively unexplored. By employing the modified Sardar sub-equation method, which has demonstrated effectiveness in solving nonlinear evolution equations, this study aims to bridge this gap. The soliton solutions obtained encompass a wide spectrum of behaviors, including bright, dark, periodic, singular, dark-periodic, bright-periodic, dark-singular, compactons, and bright-singular soliton solutions, as well as other complex phenomena. The comprehensive exploration of soliton solutions not only enhances our understanding of fundamental wave phenomena but also provides valuable insights for addressing nonlinear equations across various scientific disciplines, including optical fiber communications, plasma physics, and nonlinear dynamics. [ABSTRACT FROM AUTHOR]

The article explores the historical significance and future developments of fiber materials, tracing their evolution from natural fibers to synthetic and smart fibers. It highlights key breakthroughs such as the development of nylon and optical fibers, emphasizing their impact on various industries and technologies. The text also discusses current advancements in fiber science, including the reconstruction, intelligence, miniaturization, and extremization of fibers, as well as proposed research directions focusing on computation, greenization, and integration. The article underscores the transformative potential of advanced fiber materials in fields ranging from space research to precision medicine, posing the question of whether future fibers will retain their traditional characteristics. [Extracted from the article]

The article discusses the development of multimaterial fibers that integrate polymers, glasses, and metals into a single structure for various applications. It highlights the importance of engineering in creating practical fibers through thermal drawing, allowing for the combination of different materials at high temperatures. The recent work by Wang et al. focuses on fabricating glass-clad semiconductor fibers that can be convergently drawn with conductive polymers and metals, resulting in multifunctional fibers used in electronic and optoelectronic devices and wearable structures. This innovative research showcases the potential of multimaterial fibers and wearable technologies for future advancements in the field. [Extracted from the article]

Abstract HVE-400 ion implanter is special ion implantation equipment for semiconductor materials boron and phosphorus doping. The ion source and extraction deflection system are at high voltage platform, while the corresponding control system is at ground voltage position. The control signals and measurement signals of various parameters at the high-voltage end need to be transmitted between ground voltage and high voltage through optical fibers to isolate high voltage. Upgrading is carried out due to the aging of the optical fiber transmission control and monitoring system, which cannot work stably. The transformation replaces the original distributed single-point control method with an advanced distributed centralized control method, and integrates all control and monitoring functions into an industrial control computer for digital operation and display. In the computer software, two kinds of automatic calculation of ion mass number are designed. After upgrading, the implanter high-voltage platform control and monitoring system features digitalization, centralized control, high reliability, strong anti-interference, fast communication speed, and easy operation.

Given the ever‐increasing demand for transmission capacity in optical fiber communication systems, there is a growing focus on developing active fibers and devices with an optical response across a wider spectrum. Bismuth (Bi)‐doped photonic glasses have attracted significant interest for their exceptional ultra‐broadband optical response, particularly within telecommunication bands. However, developing advanced Bi‐activated materials with robust optical response, high compatibility with commercial transmission systems, and low processing temperature remains a huge challenge. Herein, an anion hybridization strategy is proposed to overcome the aforementioned limitations. The anion hybridization significantly enhances the broadband optical response (≈10 times) of the Bi center following the introduction of fluorine ions, and reduces the transition temperature of the photonic glass (≈200 °C). Moreover, the near‐infrared optical response bandwidth experiences significant broadening, a result attributed to the larger inhomogeneous broadening. Furthermore, successful fabrication of the anion‐hybridized Bi‐activated glass fiber is achieved, demonstrating excellent compatibility with commercial transmission fibers. Additionally, the fabricated fiber exhibits an amplified spontaneous emission and on‐off gain across a broad waveband, further validating its efficacy. These results indicate that anion hybridization offers an effective strategy to optimize the optical and thermal properties of photonic materials to develop novel advanced photonic devices. [ABSTRACT FROM AUTHOR]