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Photonic lantern is a key device in space division multiplexing (SDM) system. The key challenge of a photonic lantern is mode scalability, which requires the taper length to increase nonlinearly as the mode number scales up. The traditional photonic lantern fabrication method requires stacking the input fibers into the hollow, low-index outer cladding before tapering. It implicitly sets geometric constraints on the input fibers' core positioning. We propose a photonic lantern design with drilling preform and reduced cladding fibers to lift these constraints and make photonic lanterns more adiabatic. By analyzing the effects of loosening the constraints on the adiabatic requirement of a three-mode photonic lantern, we find further progress could be made to alleviate this adiabatic requirement. The optimal structure for our design is proposed and demonstrated through the beam propagation method (BPM). Our findings could help further improve the mode scalability of photonic lanterns. [ABSTRACT FROM AUTHOR]

Optical backbone networks, characterized by using optical fibers as a transmission medium, constitute the fundamental infrastructure employed today by network operators to deliver services to users. As network capacity is one of the key factors influencing optical network performance, it is important to comprehend its limitations and have the capability to estimate its value. In this context, we revisit the concept of capacity from various perspectives, including channel capacity, link capacity, and network capacity, thus providing an integrated view of the problem within the framework of the backbone tier. Hence, we review the fundamental concepts behind optical networks, along with the basic physical phenomena present in optical fiber transmission, and provide methodologies for estimating the different types of capacities, mainly using simple formulations. In particular, we propose a method to evaluate the network capacity that relies on the optical reach to account for physical layer aspects, in conjunction with capacitated routing techniques for traffic routing. We apply this method to three reference networks and obtain capacities ranging from tens to hundreds of terabits/s. Whenever possible, we also compare our results with published experimental data to understand how they relate. [ABSTRACT FROM AUTHOR]

The wavelength 1550 nm is widely used in fiber-optic communications and imaging systems. Avalanche photodiodes (APDs) offer high sensitivity for detecting this wavelength. However, the noise caused by the stochastic nature of the impact ionization gain mechanism can temper the benefit of amplifying the signal. Here, we report a separate absorption, charge, and multiplication APD that uses a two-step staircase multiplication region exhibiting a near-unity excess noise factor. At a gain of four, the excess noise factor is approximately three times lower than conventionally used InGaAs/InP separate absorption, charge, and multiplication APDs. This improved excess noise coupled with 1550-nm operation offers the potential for enhanced performance in several key application areas. [ABSTRACT FROM AUTHOR]

With the rapid development of 5G networks, the Internet of Things, and new‐generation of AI, there are considerable demands on expanding the capacity of contemporary optical fiber communication systems. One of the most effective avenues involves the extension of the bandwidth of Er‐doped fiber amplifiers, but with limited success. Herein, an Er‐activated hybridized glass fiber are reported, which can help realize broadband telecommunication. The effect of element hybridization on the bandwidth of Er‐activated fiber is clarified and the structure‐optical response relationship is established. A two‐step deposition approach is proposed to overcome the immiscibility barrier of different hybridized elements, and Er‐activated fiber with uniform doping is constructed. The activated fiber presents excellent compatibility with commercial telecommunication systems, providing a small signal gain of >13 dB in the whole L‐band range and a maximum gain of 28 dB. Furthermore, the Er‐activated fiber amplifier device is successfully developed. It exhibits outstanding optical amplification performance with gain >24 dB in the range of 1580–1624 nm, gain fluctuation less than ±0.9 dB, and noise figure <6.5 dB. The results not only provide a new strategy for developing novel active broadband optical fibers, but a valuable solution for new‐generation large‐capacity optical fiber communication systems. [ABSTRACT FROM AUTHOR]

The goal of this work was to use conformable fractional derivative sense to create some crucial solitary waves for two models of space–time fractional nonlinear Schrödinger equations. We use the unified solver approach to accomplish this goal in a fully unified way. This solution is robust, practical, dependable, and simple to use. The obtained solutions are extremely important for describing critical complicated phenomena in fractional quantum mechanics, optical fiber communications, and energy applications. Some simulations are provided to demonstrate the behavior of the obtained solutions when appropriate physical parameters are used. It was noted that by increasing the fractal factors, the nonlinear wave propagates with a changing phase and wave frequency. Our research may open up new possibilities for optical manipulation in practical applications. Finally, further fractional physical models can be solved using the suggested technique. [ABSTRACT FROM AUTHOR]

Technical Assistance and Support Center, NTT EAST developed the Optical Loss Prediction Tool 1.0 for predicting transmission loss of optical fibers. This article presents an overview and the functions of this tool. This is the eightieth article in a series on telecommunication technologies. [ABSTRACT FROM AUTHOR]

In recent years, with the development of smart grids, people have increasingly high requirements for the safety, stability, and reliability of smart grid operation. In actual operation, smart grids require real-time monitoring and control, while for low-voltage power lines, power line carrier communication is required for data transmission. However, in practical applications on site, the low-voltage power line environment is complex, with ground faults, electrical equipment interference, and other situations that can affect communication quality and reliability, leading to a decrease in the effectiveness of real-time monitoring and control. The research in this paper is based on a complex low voltage platform simulation platform to restore the on-site complex substation communication environment. The purpose is to improve the efficiency of automatic meter reading systems by using various communication methods in low-voltage substations, such as wireless public network point-to-point data transmission, optical fiber communication data transmission, power line carrier data transmission, etc. Automatic meter reading systems are an important means of low voltage substation communication. This article experimentally tested the maximum personnel allocation for meter reading using low voltage carrier communication technology, which was 8 people smaller than the maximum personnel allocation for traditional meter reading, and the minimum personnel allocation was 8 people smaller than the traditional meter reading personnel allocation. The electricity accuracy of meter reading using low voltage carrier communication was up to 96 %, while the electricity accuracy of traditional meter reading was 70 %. The maximum accuracy of line loss statistics for low voltage carrier communication technology meter reading was 90 %, while the maximum accuracy of line loss statistics for traditional meter reading was 68 %. The frequency of load anomalies found in low-voltage carrier communication meter readings within a month ranged from 30 to 60 times, while the traditional meter readings concentrated on 10–25 times. From these data, it is clear that communication meter reading in low-voltage station areas has advantages over traditional meter reading. [ABSTRACT FROM AUTHOR]

To meet the growing demand for communication capacity, new multi-carrier fiber optical communication technology has become the focus of scientific researchers' attention. The paper reviews the development process of traditional Orthogonal Frequency Division Multiplexing (OFDM) in the field of fiber optical communication in the past 20 years and summarizes the relevant research on Filter Bank Multi Carrier (FBMC) and Universal Filter Multi Carrier (UFMC) in recent years. Since 2016, many scholars at home and abroad have focused on the drawbacks of OFDM in optical communication, such as high out-of-band leakage, reliance on Cyclic Prefixes (CP), high Peak-to-Average Power Ratio (PAPR) values, and high system synchronization requirements. They have been researching new multi-carrier systems as a breakthrough point. FBMC optical communication has the characteristics of the lowest sidelobe power and high spectral efficiency, but due to the use of Offset Quadrature Amplitude Modulation (OQAM), the corresponding Digital Signal Processing (DSP) algorithm needs to be redesigned or virtual part interference. UFMC optical communication has a strong tolerance for time synchronization deviation, and it is insensitive to frequency offset. Moreover, it can reuse the DSP algorithms of OFDM. However, there are also issues such as how to further suppress out-of-band power and reduce computational complexity. Finally, based on the current research status, he paper proposes research directions and suggestions for the demands of the next-generation fiber optical communication system. [ABSTRACT FROM AUTHOR]

The deep integration of optical fiber communications and high-capacity high-frequency wireless communications is the core technology base of future The 6th Generation Networks(6G). It holds significant importance in building typical 6G scenarios such as "immersive communications, ubiquitous connectivity, and communications Artificial Intelligence (AI) integration". This paper introduces mainstream technologies and their implementation for optimizing the architecture and improving the spectral efficiency of fiber-wireless integrated transmission systems. We summarize some of the progress made by our team in these areas. First of all, facing the large-capacity demand for a new generation of immersive communications, we propose a novel architecture for seamless "fiber-wireless-fiber" integrated transmission system with the use of commercial Digital Coherent Optics(DCO). We firstly realize the photonics-assisted 100/200/400 GbE real-time THz wireless transmission, achieving a maximum line rate of 2X240. 558 Gbit/s. Secondly, for application scenarios with wide coverage and flexible deployment, Digital Sub Carrier Multiplexing (DSCM) technology was introduced into the optical fiber wireless converged access system. Our team designs and constructs a coherent Passive Optical Networks (PON) that supports up to 32 channel of fixed broadband access and 32 channel of W-band millimeter-wave wireless access. This coherent PON can reach the rate of 100 Gbit/s and is capable of flexible rate adjustments, facilitating subsequent iterative upgrades. Finally, in response to the demand for communication AI integration, our team proposes a likelihood-aware Vector-Quantization (VQ) Variational Auto Encoder (VAE) based on AI technology for end-to-end optimization of fiber-wireless integrated communication systems. Without the need for tera-hertz power amplifiers, we successfully demonstrate the wireless transmission of Dual-Polarization (DP) terahertz signal at a net rate of 366. 4 Gbit/s over 6.5 m 2 X 2 Multiple Input Multiple Output (MIMO) wireless link and 20 km Standard Single Mode Fiber (SSMF) link. The aforementioned technologies exhibit tremendous potential in typical future 6G scenarios. Besides, we briefly introduce our work in these areas, and provide an outlook on beyond 100 Gbit/s fiber-wireless integrated transmission technology from the perspectives of high capacity, long distance, integration and intelligentization. [ABSTRACT FROM AUTHOR]

This document provides a comprehensive list of upcoming conferences and events focused on glass and glass science. These conferences are being held in various countries such as the UK, Portugal, France, USA, Germany, and South Korea. The topics covered in these conferences range from industrial furnaces and boilers to glass craft and bead expo, photonics, sustainable materials, and glass processing automation. The document also includes contact information for each event, making it a valuable resource for individuals interested in these topics. [Extracted from the article]

In this paper, we investigate the (2+1)-dimensional nonlinear Schrödinger equation (NLSE) which characterizes the transmission of optical pulses through optical fibers exhibiting refractive index variations corresponding to light intensity changes. Traditional numerical methods typically require a substantial amount of data to ensure the accuracy when solving high-dimensional NLSE, resulting in high experimental costs as well as a significant demand for storage space and computing power. With physical knowledge embedded into deep neural networks, physics-informed neural network (PINN) has been widely applied to solve various complex nonlinear problems and achieved significant results with small amount of data. Setting different groups of initial conditions and boundary conditions with hyperbolic and exponential functions, we construct the corresponding loss functions which will be further applied to train PINN. All data studied here is generated on Python. Based on the predicted results, we depict different types of optical pulses. According to our data experiments, lower prediction errors can be achieved with small volume of data, which fully demonstrates the effectiveness of the PINN. In the meantime, we also perform data-driven parameter discovery to the (2+1)-dimensional NLSE to study the coefficients of the group velocity dispersion and self-phase modulation terms. It can be seen that the PINN has high accuracy and robustness for parameter discovery to the (2+1)-dimensional NLSE. In brief, the use of PINN greatly enriches the diversity of solving methods, providing a reference for research of (2+1)-dimensional solitons in the field of optical fiber communications. [ABSTRACT FROM AUTHOR]

With the vigorous development of emerging technology and the advent of the Internet generation, high-speed Internet and fast transmission 5G wireless networks contribute to interpersonal communication. Now, the Internet has become popular and widely available, and human life is inseparable from various experiences on the Internet. Many base stations and data centers have been established to convert and switch from electrical transmission to optical transmission; thus, it is entering the new era of optical fiber networks and optical communication technologies. For optical communication, the manufacturing of components for the purpose of high-speed networks is a key process, and the requirement for the stability of its production conditions is very strict. In particular, product yields are always low due to the restriction of high-precision specifications associated with the limitations of too many factors. Given these reasons, this study proposes a hybrid fuzzy control-based model for industry data applications to organize advanced techniques of box-and-whisker plot method, association rule, and decision trees to find out the determinants that affect the yield rate of products and then use the fuzzy control Proportional-Integral-Derivative (PID) method to manage the determinants. Since it is unrealistic to test the real machine online operation at the manufacturing stage, the simulation software supersedes this for improved results, and a mathematical neural network is used to verify the given data to confirm whether its result is similar to that of the simulation. The study suggests that excessive temperature differentials between substrate and cavity can lead to low yields. It suggests using fuzzy control technology for temperature management, which could increase yield, reduce labor costs, and accelerate the transition to high-speed networks by mass-producing high-precision optical filters. [ABSTRACT FROM AUTHOR]

In this study, we endeavored to create and simulate a D‐type flip‐flop utilizing two‐dimensional photonic crystals featuring a square lattice. This flip‐flop, composed of just two intersecting waveguides, is both compact and straightforward. Constructed from 10 × 10 dielectric rods suspended in air, it boasts low output power in logic mode 0, creating a significant distinction between optical powers in modes 0 and 1, lending it a logical aspect. Optimized for operation at a communication wavelength of 1.55 µm, this flip‐flop proves suitable for optical communication systems. The third window optical fiber communication system is suitable for 1.55 μm wavelength because the fiber has the lowest loss. Our analysis involved calculating the band structure via the plane wave expansion method and determining the optical power distribution using the finite difference time domain method. [ABSTRACT FROM AUTHOR]

This paper proposes an efficient optical fiber communication scheme for an optical metro access network (OMAN) based on an optical multicarrier (OMC) generator. The central office (CO)'s foundation is a novel, cost‐effective OMC‐generating technique. The OMC is designed from a pulsed laser source and three cascaded electro‐optic modulators (EOMs) driven by an amplified RF source of 20 GHz signal that has generated more than 60 frequencies with excellent tone‐to‐noise ratio (TNR) ~ 40 dB and amplitude excursions from zero to 3 dB. The conventional CO is replaced with a cost‐effective OMC‐based source with an effective switching mechanism, which is necessary and equally important to be handled reliably. The downstream data of 20 Gbps per carrier is transmitted using a duo‐binary coding scheme. Six remote nodes (RNs) supported by the suggested OMC source, at each RN 10 optical network units (ONUs), can be deployed having distance laps of 5 km between the RNs, the distance between the RNs and the ONUs is kept at 2 km, the ONUs were tested w.r.t the bit error rate (BER) and the power penalties for the proposed transmissions. The BER for different fiber lengths from 5 to 25 km at various RNs and ONUs ranges were calculated and demonstrated from 1e−3 to 1e−13, showing the feasibility of the proposed OMAN. [ABSTRACT FROM AUTHOR]

The optical pulse generator model in Optisystem 20 is utilized to generate an optical soliton pulse. The performance evaluation of highly modulated soliton power transmission is carried out on both optical fiber and optical wireless communication channels. The evaluation considers a flow rate of 40 Gbps and a link distance, which is not specified in the provided context. Among the proposed modulation schemes, which include CPFSK, FSK, and PSK, CPFSK demonstrates superior performance for both communication channels. Increasing the number of bits per symbol enhances the bit error rate (BER) at the fiber or wireless channel, as received by the optical receiver, for different modulation schemes, except for the CPFSK scheme. Thus, it is evident that the CPFSK modulation scheme is more efficient and outperforms other modulation schemes for various communication channels. Hence, it is evident that the CPFSK modulation scheme exhibits superior efficiency and outperforms other modulation schemes for a variety of communication channels. [ABSTRACT FROM AUTHOR]

NTT Research and Development Planning Department released the NTT IOWN Technology Report 2023, which summarizes its vision for the Innovative Optical and Wireless Network (IOWN), the concept of which was unveiled in 2019, and technologies intended to make the world a better place for everyone. This article provides an overview of this report. [ABSTRACT FROM AUTHOR]

In order to deal with the chromatic dispersion-induced power fading issue for short-reach direct-detection optical fiber communication applications, such as the ever-increasing data-center interconnections (DCIs), optical filed recovery is intensively being under investigation. To date, various direct detection schemes capable of optical field recovery have been proposed, including the Kramers–Kronig (KK) receiver, asymmetric self-coherence detection (ASCD) receiver, carrier-assisted differential detection receiver (CADD), Stokes vector receiver (SVR), and carrier-free phase-retrieval (CF-PR) receiver. Among those, the CF-PR receiver attracts lots of research attention because it can circumvent the requirement of a strong continuous-wave (CW) optical carrier for the beating with the signal. Generally, the CF-PR receiver consists of only two single-ended photodiodes (PDs) and one dispersive element, for the field recovery of the quadrature amplitude modulation (QAM) signals. Based on the theoretical and experimental studies reported so far, this paper reviews the latest progress of CF-PR receivers designed for high-speed optical short-reach transmission links. [ABSTRACT FROM AUTHOR]

This article presents an experimental investigation of polarization pulling based on stimulated Raman scattering induced by a continuous, fully polarized pump wave in an optical fibre. By means of probe wave states of polarization aggregation, degree of polarization and gain analysis, an assessment of all-optical polarization control, repolarization and amplification in a standard single mode fibre in depleted pump regime is presented. Polarization pulling is proved to be dependent on fibre length, pump power, and pump state of polarization, with respect to pump depletion effect, acting oppositely to the polarization pulling effect. Authors evaluate results aiming to obtain a configuration of stimulated Raman scattering parameters, which allows for the most effective polarization pulling, with respect to statistical stability of the process measured by standard deviation of polarization degree and polarization-dependent gain of the probe wave. The highest polarization attraction efficiency was obtained for 15 km, 0.97 W and the horizontal polarization state of the pump wave. [ABSTRACT FROM AUTHOR]

This study investigates and compares the performance of a 10 Gbps optical communication link utilizing two prevalent single-mode fibers: G.652 and G.655. The analysis employs both theoretical calculations and Python-based simulations to assess the effectiveness of each fiber type in this high-speed transmission scenario. With the ever-growing demand for bandwidth in communication networks, 10 Gbps transmission systems are becoming increasingly commonplace. Single-mode fibers like G.652 and G.655 play a vital role in these systems, offering low signal attenuation for long-distance data transmission. However, each fiber type exhibits distinct dispersion characteristics, which can impact signal integrity over extended distances. This investigation adopts a two method for performance evaluation. Firstly, link power budget calculations are performed to determine the optical signal power before and after propagating through a 50-kilometer fiber span. The received power serves as the foundation for subsequent Q-factor and Bit Error Rate (BER) analysis. These calculations establish the theoretical limitations of the system based on well-defined formulas. Secondly, Python-based simulations are conducted to corroborate the theoretical findings and provide a more comprehensive performance assessment. This approach leverages the capabilities of two prominent Python packages: Opticomlib and OpticommPy. Opticomlib excels at analyzing the behavior of individual optical pulses within the system, enabling an understanding of the signal propagation. On the other hand, OpticommPy specializes in parameter sweep analysis, allowing for the investigation of how critical parameters like received power influence the Q-factor. By combining these functionalities, the simulations provide a detailed picture of the system's performance under various conditions. The calculated BER and Q-factor values for both G.652 and G.655 fiber links surpass the industry-accepted performance standards. These results demonstrate the effectiveness of using Python-based tools for comprehensive performance analysis of optical communication systems. However, it's important to note that slight discrepancies exist between the calculated and simulated results.

With the increasing use of optical fiber communication technology in the Industrial Internet of Things, cryptographic algorithms play a crucial role in ensuring the security of data transmission in embedded device environments.The SM4 packet cipher algorithm, developed independently in our country, is widely applied to wireless LAN and Internet of Things data encryption.However, the software-based encryption and decryption processes are relatively slow, which hampers their application in scenarios requiring high real-time performance, especially for embedded devices.To address this issue, a high-performance and secure optical fiber communication system was designed based on the FPGA platform and the SM4 algorithm.The FPGA was used to implement the MAC layer interface for SM4 algorithm encryption and decryption, as well as data transmission.Besides, an optimization scheme for the hardware implementation architecture of the SM4 algorithm was proposed.The critical path was shortened by employing a pipeline method, thereby improving the system clock frequency.Additionally, parallel processing of S-box transformation was accelerated to enable efficient data replacement.To reduce data reading delays, a dual-cache processing method was combined to facilitate easier processing of cache data and significantly reduce packet loss rates.This scheme greatly enhanced system data throughput.Experimental results demonstrate that compared to similar designs, the throughput of the SM4 algorithm encryption and decryption module in this scheme reaches up to 25.6 Gbit/s, with minimal differences in resource consumption.Due to limitations imposed by the 10-gigabit SFP+ optical module, the throughput of the entire optical fiber communication system reaches 9.4 Gbit/s.For 128-bit data, the average encryption speed is 0.47 μs/bit and the average decryption speed is 0.28 μs/bit, which can be applied to a variety of secure communication scenarios in the internet of things.

With the growth of network traffic, communication services have higher and higher requirements on the performance of Dense Wavelength Division Multiplexing (DWDM). In order to improve the transmission efficiency, the transmission spectrum gradually expands to the C+L band transmission, and Super C Band transmission emerges as the times require. In order to solve this problem, this paper proposes an Erbium-Doped Fiber Amplifier (EDFA) structure for Super C Band transmission. Based on the Giles model, the characteristics of the EDFA in Super C Band are analyzed. A multi-stage pumping mechanism is used to design an EDFA that amplify in the Super C Band range. The results show that the EDFA can achieve a flat gain of 26 dB and an output power of 16.7 dBm when the light is incident at -9.3 dBm. The noise figure is less than 5 dB, and the ripple is less than 0.1 dB. And according to the requirement, when the incident light is in the range of -15～-3.5 dBm, the adjustable gain of 7～26 dB can be achieved by adjusting the pump power and the value of Variable Optical Attenuator (VOA). The EDFA can be used in the area of 5G transmission, optical fiber communication between data centers, etc.

This paper reports for the first time an in-depth study based on first-principle calculations to unveil the underlying physics that governs the pressure induced structural phase transitions of Hg2Cl2 compound at room temperature. The phonon dispersion relations and phonon density of states have been critically explored for the tetragonal and orthorhombic phases of the compound to unveil the phonon modes associated with the phase transitions. The nature of the phase transition whether it is "displacive" or of "order–disorder" type has also been explored. We believe that the present study based on density functional theory and Born–Oppenheimer molecular dynamics calculations will help understand the underlying physics behind the above referred phase transitions and the anisotropic behavior of the compound, which in turn bears technologically significant relevance for its applications in optoelectronic devices, acousto-optic tunable filters, and in fiber-optic communication systems. [ABSTRACT FROM AUTHOR]

Modern communication generation for high data rate requirement is fifth generation. The fifth generation has many advantages like low delay, high spectrum availability, high reliability, low jitter, and more capacity. To combat with the high capacity and high data rate requirement, optical fiber helps in the backhaul of 5G network. When fiber is used as a mode of propagation, many nonlinearities arises. This nonlinearity effect in the optical fiber communication is one of the most undesirable phenomena for the modern communication system which results in harmonic distortion, intermodulation distortion, phase distortion, and adjacent channel interference, etc. In most fiber optic communication systems, the major fiber nonlinear effect is the Kerr nonlinearity and Scattering effect that produced due to the variation of refractive index due to signal intensity. To minimize the effect of nonlinear distortion, some techniques are used which considerably improve the transmission capacity by reducing or compensating the effect of nonlinear distortion along with minimal infrastructure modifications and minimum cost for implementation. To overcome the effect of nonlinearity, fiber nonlinearity mitigation techniques are preferred to achieve the significant performance gains. Mitigation techniques can be implemented to improve and optimize the performance of optical communication network. In this paper, a brief description of the fiber nonlinearity effect and a review of various fiber nonlinearity compensation techniques are described. [ABSTRACT FROM AUTHOR]

In both optical wireless and optical fiber communication, orthogonal frequency division multiplexing (OFDM) plays an important role in data transmission. In the similar context, DC-coupled optical (DCO) OFDM and asymmetrically clipped optical (ACO) OFDM are discussed. DCO-OFDM has better peak to average power ratio (PAPR) but bit error rate (BER) performance is poor; however, in case of ACO-OFDM, PAPR is poor but BER performance is good. Moreover, DCO-OFDM is more power hungry; therefore, ACO-OFDM is considered as a preferred choice. Recently, asymmetrically clipped DC-biased optical (ADO)-OFDM is proposed, which shows good PAPR and BER performance. Clipping and µ-law companding techniques are discussed for PAPR reduction. The mathematical model is developed for all the three methods for received signal while considering clipping and companding noises along with channel noise. It is found that ADO-OFDM is better choice in comparison to DCO and ACO-OFDM. However, in case of ADO-OFDM, receiver structure is more complex. [ABSTRACT FROM AUTHOR]

The numerical modeling of short optical pulses propagation in the communication link is carried out. The combination of high chirp and variable dispersion compensation is proposed to suppress the nonlinear noise. The variable dispersion decreases the bit error rate by 10 times. Calculations for 25 ps pulses propagating by 1000 km with 8-level amplitude-phase modulation and two polarization states confirm that the chirp and compensation decrease the nonlinearity effects and improve the quality of detection radically. The results can be useful when choosing a high-speed communication line design. [ABSTRACT FROM AUTHOR]

Recently, in the present day's data center systems an explosive growth has been observed in data traffic, which restricts the speed of exiting data communication network. To solve such problem, fiber optical-based optical communication system is preferred choice. In this paper, an arrayed waveguide grating (AWG)-based optical packet switch is presented in which priority among packets is implemented effectively. This switch is a recirculating loop buffer-based switch in which a hybrid buffering (optical + electrical) technique is used for storing packets into the buffer. The power budget analysis of switch is presented in various conditions, when packet passes through the optical or electronic buffers. Comparison of optical and electronic buffering is done in terms of power required for the correct operation of the switch. In this paper, a comparison is performed between our proposed switch with recently published switch designs. The result presented in this paper clearly reveals that the performance of our proposed switch is far better than other previously published switch architecture. The major beauty of our proposed switch is that in this design priority among packets implemented effectively. [ABSTRACT FROM AUTHOR]

Light beams possess various dimensions, such as wavelength, spin angular momentum (SAM), and orbital angular momentum (OAM), which are indispensable in numerous optical applications. However, traditional techniques entail multiple attempts to disclose desired optical information, utilizing unwieldy multi‐pass systems or mechanically moving parts that are cumbersome to integrate into compact and integrated optical systems. Here, a single‐layer dielectric metasurface platform is proposed that enables multi‐dimensional demultiplexing and decoding, circumventing the need for conventional bulk optical elements. The platform can demultiplex 3D light parameters (wavelength, SAM, and OAM) and focus them at distinct spatial positions on a designated focal plane, providing a superior alternative to far‐field beams for integration with optical fiber and communication chips. The study verifies 132‐bit independent channels for a multi‐dimensional demultiplexer and demonstrates the metasurface‐based component's ability to function as an elliptic polarization decoder through a 4‐bit elliptic polarization coding transmission experiment. This work provides a compact and efficient platform for demultiplexing multi‐dimensional SAM and OAM states over a broad wavelength range, with potential implications for optical communications, optical data storage, optical information encryption, and quantum information sciences. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the impact of the integrability criterion on mixed-derivative nonlinear Schrödinger equations, specifically focusing on the Rangwala-Rao (R R) equation introduced by A. Rangwala in 1990. Our objective is to enhance our understanding of the dispersion effect by examining innovative soliton wave solutions and their interactions. The tanh method is utilized to generate unique solitary wave solutions for the Rangwala-Rao (R R) equation. The study of the Rangwala-Rao (R R) holds significance as it has the potential to contribute to the development of more efficient optical fiber communication systems. The numerical solutions presented in this research illustrate the dynamic nature of optical fiber pulse propagation, underscoring the distinctiveness of this work compared to previous scholarly endeavors. The study obtained various soliton solutions, including rational, trigonometric, and hyperbolic functions. The results are presented in graphical form with appropriate parameter values to aid visualization. The originality of our computed outcomes, which represent novel achievements that surpass previously derived solutions, becomes evident when we compare our accomplishments with theirs. These newly examined results are innovative and novel, with the potential to significantly propel the realms of nonlinear optics and mathematical physics forward. This study proves that the computational method used is efficient, brief, and widely applicable, making it valuable to engineers who work with engineering models and dynamical models. [ABSTRACT FROM AUTHOR]

In this work, we realised the soliton solutions of nonlinear Schrödinger equation (NLSE) that arise from optical fibers, we considered the modified Sardar sub-equation method (MSSEM) to find solitary solutions analytically. The stability of the retrieved soliton solutions realised from the NLSE are investigated. We demonstrate the soliton solutions that are stable and can last for a very long time without losing its form or energy under specific circumstances and those soliton solutions that are unstable. The MSSEM is a frequently employed technique in research for addressing specific mathematical modeling or physical phenomena problems. Its selection in this specific study might stem from its proven efficacy in handling the particular problem under investigation. The decision to utilize MSSEM could be driven by several considerations, including its precision, computationally efficient, effectiveness, greater accuracy and capability to manage intricate systems. Finally, our method offers greater flexibility in modeling various physical phenomena, which makes it particularly useful in applications in diverse fields such as quantum mechanics and nonlinear optics. The findings have ramifications for the architecture of optical fiber communications and offer significant new insights into the behavior of solitons in optical systems. The NLSE has proven to be an effective tool for understanding wave behavior in fiber optics. Its applications have helped engineers and scientists optimize the design of optical fibers and predict the behavior of various conditions. Moreover, our study provides insights into the fundamental properties of solitary solutions in the NLSEs and their practical implications in physical systems. [ABSTRACT FROM AUTHOR]

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This article presents a bidirectional optical fiber communication system employing Dual Polarization-64 Quadrature Amplitude Modulation and Digital Signal Processing (DP-64QAM and DSP). With sixteen channels operating at 120 Gb/s each, the system achieves a total capacity of 1920 Gbps. OptiSystem V.19 software simulations confirm compliance with ITU-T 5G fronthaul requirements in G-series Recommendations-Supplement 66. Performance evaluation focuses on Bit Error Rate (BER), incorporating an Optical Signal-to-Noise Ratio (OSNR) and an adaptable optical span. Simulation results establish the system's suitability as an F1 and Fx 5G fronthaul link for functional splits of 1 to 7c, aligning with ITU-T stipulations (<120 Gbps per channel). The design employs a bidirectional single-mode optical fiber for up to 13 km and 13.5 km distances in downlinks and uplinks. Incorporating two Dispersion Compensator Filters (DCFs) extends this to 19.5 km. This enhancement underscores the adaptability for real-world applications, particularly in extended-range scenarios necessitating robust and high-capacity communication links. [ABSTRACT FROM AUTHOR]

The near‐infrared (NIR) light polarization metrology is crucial in a broad area of applications, such as optical sensing, imaging, and communications. The conventional measurement of NIR light polarization requires bulky polarization optics by the spatial or temporal splitting of the input light beam with expensive infrared detectors. Here, an intelligent fiber‐integrated NIR polarimeter based on upconversion nanoparticles (UCNPs) is demonstrated. Er‐doped UCNPs are synthesized in core–shell structures for bright upconversion luminescence (UCL), and the tapered multimode fiber (MMF) is designed for random Rayleigh‐distributed speckles. It is demonstrated for the first time that spectra‐polarization‐dependent upconverted speckle patterns captured by a cost‐effective visible image sensor can be accurately decoded via a deep neural network (ResNet50). The experimental results show that ResNet50 has a recognition accuracy of over 99.5% for the full‐Stokes parameters of NIR light polarization, along with 100% accuracy for the light wavelength ranging from 1535 nm to 1565 nm. The developed intelligent optical sensors provide a new design paradigm for fiber‐integrated multi‐dimensional NIR light field detection and can be applied in fiber‐optic sensors and communications networks. [ABSTRACT FROM AUTHOR]

Optical layer attacks on optical fiber communication networks are one of the weakest reinforced areas of the network, allowing attackers to overcome security software or firewalls when proper safeguards are not put into place. Encrypting data using a random phase mask is a simple yet effective way to bolster the data security at the physical layer. Since the interactions of the random phases used for such encryption heavily depend on system properties like data rate, modulation format, distance, degree of phase randomness, laser properties, etc., it is important to determine the optimum operating conditions for different scenarios. In this work, assuming that the transmitter and the receiver have a secret pre-shared key, we present a theoretical study of security in such a system through mutual information analysis. Next, we determine operating conditions which ensure security for 4-PSK, 16-PSK, and 128-QAM formats through numerical simulation. Moreover, we provide an experimental demonstration of the system using 16-QAM modulation. We then use numerical simulation to verify the efficacy of the encryption and study two preventative measures for different modulation formats which will prevent an eavesdropper from obtaining any data. The results demonstrate that the system is secure against a tapping attack if an attacker has no information of the phase modulator and pre-shared key. [ABSTRACT FROM AUTHOR]

Phase encoding in quantum key distribution (QKD) enables long-distance information-theoretic secure communication in optical fibers. We present a novel theoretical model characterizing errors from various sources in practical phase encoding-based QKD systems, namely the laser linewidth, detector dark counts, and channel dispersion. This model provides optimized optical pulse parameters and less distortion in pulses, which eliminates system imperfections and leads to a reduced quantum bit error rate (QBER) for practical QKD scenario. This analysis is applicable to various fiber-based phase and time encoding protocols. In particular, we implement this to a differential phase shift (DPS) QKD scheme operating at a 2.5 GHz clock, which produces a secure key rate of 193 bits/s at a fiber length of 265 km and an unprecedented QBER < 1 % up to 225 km length with standard telecom components. We show that by adjusting the quantum efficiency and dark count rates of detectors, proposed system can establish secure keys up to 380 km distance using standard telecom grade fiber with a QBER of 1.48%. Moreover, the system is compatible with existing optical fiber networks and capable of establishing a secure key exchange between two cities 432 km apart using ultra-low-loss (ULL) specialty fiber. [ABSTRACT FROM AUTHOR]

InGaAs photodiodes have a wide range of important applications; for example, NIR imaging, fiber optical communication, and spectroscopy. In this paper, we studied InGaAs photodiodes with different doping concentration absorber layers. The simulated results suggested that, by reducing the absorber doping concentration from 1 × 1016 to 1 × 1015 cm−3, the maximum quantum efficiency of the devices can rise by 1.2%, to 58%. The simulation also showed that, by increasing the doping concentration of the absorber layer within a certain range, the dark current of the device can be slightly reduced. A PIN structure was grown and fabricated, and CV measurements suggested a low doping concentration of about 1.2 × 1015 cm−3. Although the thermal activation energy of the dark current suggested a distinct component of shunt dark current at a high temperature range, a dark current of ~6 × 10−4 A/cm2 (−0.5 V) was measured at room temperature. The peak quantum efficiency of the InGaAs device was characterized as 54.7% without antireflection coating and 80.2% with antireflection coating. [ABSTRACT FROM AUTHOR]

Tunable fiber lasers have the advantages of good beam quality, high integration, and adjustable output wavelength, and they are widely used in fields such as optical fiber communication and optical fiber sensing. The fiber filter is one of the key components of tunable fiber lasers. Among the various filters currently used, multimode interference filters have the advantages of simple structure, convenient implementation, flexible tuning methods, and convenient spectral range design. The structures of multimode interference filters based on multimode fibers, no-core fibers, multi-core fibers, tapered fibers, and other special fibers are introduced in this paper. The working principles and tuning methods are analyzed and the research progress of tunable fiber lasers based on these filters is summarized. Finally, the development trend of tunable fiber lasers based on multimode interference filters is discussed. The rapid development and applications of multimode interference filters can help improve the performance of continuous and pulse lasers as well as promote the practicality of tunable fiber lasers. [ABSTRACT FROM AUTHOR]

Electro-optic modulator (EOM) is one of the key devices of high-speed optical fiber communication systems and ultra-wideband microwave photonic systems. Silicon–organic hybrid (SOH) integration platform combines the advantages of silicon photonics and organic materials, providing a high electro-optic effect and compact structure for photonic integrated devices. In this paper, we present an SOH-integrated EOM with comprehensive investigation of EOM structure design, silicon waveguide fabrication with Slot structure, on-chip poling of organic electro-optic material, and characterization of EO modulation response. The SOH-integrated EOM is measured with 3 dB bandwidth of over 50 GHz and half-wave voltage length product of 0.26 V·cm. Furthermore, we demonstrate a microwave photonics phase shifter by using the fabricated SOH-integrated dual parallel Mach–Zehnder modulator. The phase shift range of 410° is completed from 8 GHz to 26 GHz with a power consumption of less than 38 mW. [ABSTRACT FROM AUTHOR]

Extended L-band erbium-doped fiber amplifiers (EDFAs) have attracted much attention in recent years despite their relatively low gain levels. In this paper, a dual-stage extended L-band EDFA with improved gain level is demonstrated by using an Er/Yb/P co-doped fiber-based double-pass structure assisted by a low noise pre-amplifier. High gain levels of up to 48.79 dB at 1566 nm and 20.05 dB at 1621.4 nm are achieved with saturated output power at 1605 nm of 20.58 dBm under a total pump power of only 400 mW. Bandwidths with the gain of more than 20 and 30 dB are reached up to 66 nm (1555.4–1621.4 nm) and 58.4 nm (1557.5–1615.9 nm), respectively. The noise figure benefited by using the low noise pre-amplifier is 5.40 ± 1.55 dB in the 1565–1610 nm range. The wide gain bandwidth, high gain level and relatively low pump power give it great potential for future high-capacity optical fiber communication systems. [ABSTRACT FROM AUTHOR]

The attenuation of ocean surface waves during seasonal ice cover is an important control on the evolution of Arctic coastlines. The spatial and temporal variations in this process have been challenging to resolve with conventional sampling using sparse arrays of moorings or buoys. We demonstrate a novel method for persistent observation of wave‐ice interactions using distributed acoustic sensing (DAS) along existing seafloor fiber optic telecommunications cables. DAS measurements span a 36‐km cross‐shore cable on the Beaufort Shelf from Oliktok Point, Alaska. DAS optical sensing of fiber strain‐rate provides a proxy for seafloor pressure, which we calibrate with wave buoy measurements during the ice‐free season (August 2022). We apply this calibration during the ice formation season (November 2021) to obtain unprecedented resolution of variable wave attenuation rates in new, partial ice cover. The location and strength of wave attenuation serve as proxies for ice coverage and thickness, especially during rapidly evolving events. Plain Language Summary: Coasts globally are susceptible to erosion by ocean waves. In the Arctic, sea ice near the coast can serve as protection for much of the year. It is particularly challenging to measure waves and ice in this environment, which is necessary to understand the degree of buffering and project future changes. Typical ways of observing waves (e.g., buoys and underwater moorings) have lower success in coastal ice. We show a new way to observe waves and ice in these coastal regions using cables at the seabed deployed for internet connection. With the use of an instrument called an interrogator on shore, fibers in these cables can act like a series of hundreds of wave buoys. This allows us to see that waves are reduced at a variable rate throughout the ice. There are significant opportunities to learn more about the coastal Arctic using this novel technology and method. Key Points: Seafloor fiber optic cables can be used to quantify surface waves in seasonally sea ice‐covered oceansHigh spatial‐resolution wave observations may be used to study wave attenuation in ice at much finer resolution than previously possibleThe rapid evolution of the location and strength of attenuation serves as proxy for the evolution of ice itself [ABSTRACT FROM AUTHOR]

This paper introduces a new bidirectional integration approach that combines fiber sensor/free space optics (FSO) communication using an intensity and wavelength division multiplexer (IWDM) techniques-based long-distance fiber Bragg grating (FBG) sensor strain-sensing system. By implementing coarse wavelength division multiplexing (CWDM), the system achieves the simultaneous transmission of optical communication and fiber optical sensor (FOS) sensing signals, resulting in a highly capable, flexible, and cost-effective solution. The proposed FSO transmission technique addresses complex fiber cable installation concerns with topographical limitations. This bidirectional structure ensures the reliability and stability of the long-distance FBG sensor system, supported by extensive research and experimentation. A hybrid stacked gated recurrent units and long short-term memory (SGRU-LSTM) model is proposed to enhance strain measurement accuracy by predicting and measuring the central wavelength of overlapped strain-sensing FBG sensor signals. The results demonstrate the superiority of the proposed model in peak wavelength detection accuracy. The primary benefit of integrating communication and sensing is the significant reduction in construction costs by eliminating the requirement for two individual fiber optic systems, as the integration allows for a single system to fulfill both functions, resulting in more efficient and cost-effective implementation. Overall, this paper contributes to advancing long-distance FBG sensor systems by integrating fiber sensor/FSO communication and deep learning techniques, improving transmission distance, multiplexing capacity, measurement accuracy, system survivability, and cost-effectiveness. [ABSTRACT FROM AUTHOR]

In this paper, we propose an innovative channel-sensitive autoencoder (CSAE)-aided end-to-end deep learning (E2EDL) technique for joint geometric probabilistic shaping. The pretrained conditional generative adversarial network (CGAN) is introduced in the CSAE which performs differentiable substitution of the optical fiber channel model under variable input optical power (IOP) levels. This enables the CSAE-aided E2EDL to design optimal joint geometric probabilistic shaping schemes for optical fiber communication systems at varying IOPs. The results of the proposed CSAE-aided E2EDL technique show that for a dual-polarization 64-Gbaud signal with a transmission distance of 5 × 80 km, when the modulation format is a 64-quadrature amplitude modulation (QAM) or a 128-QAM, the maximum generalized mutual information (GMI) level learned via CSAE-aided E2EDL is 5.9826 or 6.8384 bits/symbol under varying IOPs, respectively. In addition, the pretrained CGAN, as a substitution for optical fiber transmission model, accurately characterizes the distortion of signals with different IOPs, with an average bit error ratio (BER) difference of only 1.83%, an average mean square error (MSE) of 0.0041 and an average K-L divergence of 0.0046. In summary, this paper delivers new insights into the application of E2EDL and demonstrates the feasibility of joint geometric probabilistic shaping-based E2EDL for fiber optic communication systems with varying IOPs. [ABSTRACT FROM AUTHOR]

The increasing demand for transmission capacity in fiber-optic communications makes multimode fibers (MMFs) attractive by enabling simultaneous multi-channel data transmission. However, inherent mode crosstalk among transmission channels limits its applicability. In this Letter, we propose to overcome this problem via wavefront shaping. By actively modulating the incident light with a special wavefront, not only the transmitted power for a specific channel can be enhanced but also crosstalk among different transmission channels can be mitigated. As a proof of concept, we experimentally demonstrated wavefront shaping assisted dual-channel optical communications through a single MMF. 10 Gbaud four-level pulse amplitude modulation signals were sent through both channels simultaneously, enabling a total bit rate of 40 Gbps. Both channels were analyzed with bit error rates below the hard-decision forward error correction limit, confirming the validity of the proposed scheme. [ABSTRACT FROM AUTHOR]

Early detection of potentially unreliable areas in optical fibers makes it possible to detect degradation of optical fibers of fiber-optic communication lines at an early stage. Early diagnostics of the physical state of optical fibers located in the laid optical cables of telecommunication systems is an important topical task. The paper presents adaptive algorithms that allow one to determine the maximum of the Mandelstam–Brillouin scattering spectrum (Brillouin frequency shift), and then the degree of tension of optical fibers. The process of determining the Brillouin frequency shift, whose values at wavelengths of laser radiation used in telecommunication systems belong to the microwave range, can be significantly accelerated if adaptive algorithms for obtaining and processing data are implemented due to a special choice of the step for the scanning frequency and the time of accumulation of measurement results. The adaptive algorithms considered in this paper make it possible to speed up the process of obtaining output results in Brillouin reflectometers by ignoring readings that do not significantly affect the final characteristics. The construction of approximate graphs of the distribution of the spectrum and tension along the length of the fiber allows the trained user of the Brillouin reflectometer to stop the analysis process in order to make corrections to the measuring process (selection of the scanning range in frequency, change in the scanning step in frequency, choice of the accuracy of the presentation of output results, change in spatial resolution, etc.), which also speeds up the testing of the selected fiber. The measurement process can also be accelerated by adaptively changing the number of averages. With a database of measured Mandelstam–Brillouin scattering characteristics of optical fibers of various types and manufacturers, the speed of obtaining tension plots can also be increased. Since the approximate value of the Brillouin frequency shift is calculated already at the initial steps of the measurement process, preliminary dependences of the tension distribution along the length of the fiber will be constructed rather quickly. [ABSTRACT FROM AUTHOR]

Ranging from optical fiber communication to optical wireless communication regimes, twisted light has drawn the prodigious contemplation of researchers. Thus far, the tricolor visible light laser diodes (TVL-LDs) have not been scrutinized for optical angular momentum (OAM), which, however, could pioneer fortuitousness towards a new paradigm of indoor wireless communication. Here, we proposed an OAM superposition of three different Laguerre Gaussian modes such as l = 0, m = 0; l = 14, m = 0; and l = 40, m = 0, and realised by utilising red, green and blue (R/G/B) LDs as independent channels and binary data streams are encoded incorporating non return to zero linecoding, exhibiting a total capacity of 45 Gbps (3 wavelengths (λ) × 3 OAM beams × 5 Gbps). The performance of R/G/B LDs is compared in a visible light communication (VLC) model at different input parameters such as link length between the irradiating source (Lambertian) and receiver detection region, transmitter half angle, incidence half angle, and optical concentrator area. We successfully performed the transmission of 45 Gbps data over a 1.4 m line of sight VLC link and 2.3 m in a non-LoS link employing TVL-LDs, while the red LDs offered excellent performance. [ABSTRACT FROM AUTHOR]

Fiber optic communications are inevitable to achieve higher data rates of modern telecom networks. After utilization of Wavelength division multiplexing, higher order modulations and polarization multiplexing, mode division multiplexing is a new dimension to achieve higher transmission capacity for optical fiber communication links. Different spatial distributions of optical energy along cross sectional area of optical fiber allows simultaneous transmission of data by considering each mode as an independent channel. During such simultaneous transmissions, possibility of mixing of signals amongst modes causes signal degradations and acts as limiting factor for bandwidth -- distance product of the link. This effect of mode coupling has been explored in this article by presenting its mathematical formulations. A simulation has been performed to study the impact of fiber constructional parameters on mode coupling using optical wavelengths used for telecommunication systems. The observations help to develop fiber for reduced mode coupling for particular group of modes and operating wavelengths. This article paves the way forward for study of mode coupling in micro and macro bending conditions for forthcoming research endeavours. [ABSTRACT FROM AUTHOR]

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This document provides a comprehensive list of upcoming conferences and events related to glass technology and materials science. These conferences are being held in various locations worldwide, including the UK, Portugal, France, USA, Germany, China, Spain, Australia, South Korea, the Netherlands, Italy, Czech Republic, Canada, and Hungary. The topics covered in these conferences range from industrial furnaces and boilers to glass craft and bead expo, telecommunications optics and photonics, renewable materials, architectural and structural applications of glass, materials in an informatics world, optical and optoelectronic materials, ceramics, non-crystalline materials, and glass manufacturing. Each event listed includes contact information for further inquiries. [Extracted from the article]