Optical Communication Transmission Research Articles

640 Gbit/s FSO turbulence-resilient field trial utilizing the cylindrical vector beam.

Free-space optical (FSO) communication has the advantages of large bandwidth and high security and being license-free, making it the preferred solution for addressing the "last kilometer" of information transmission. However, it is susceptible to fluctuations in the received optical power (ROP) due to atmospheric turbulence and pointing errors, resulting in the inevitable free-space optical communication transmission performance degradation. In this work, we experimentally verified the turbulence resistance of the cylindrical vector beam (CVB) over a 3 km long free-space field trial link. A transmission capacity of 640 Gbit/s was conducted by utilizing a 20 GBaud 16-quadrature amplitude modulation (16QAM) through eight-wavelength multiplexing. The experimental results show that the CVB exhibits stronger turbulence resilience compared to the scalar circularly polarized Gaussian beam. Under moderately strong turbulence conditions, the communication stability probability of the first-order CVB improves by about 1/3 compared to the Gaussian beam, while for that of the second-order, the CVB is improved by about 1/5.

Diffraction-free partially coherent Pearcey beam.

Partially coherent beams are renowned for their inherent resilience against environmental perturbations. However, traditional versions are prone to distortion due to light diffraction, which presents significant challenges for related applications such as information transfer. In this paper, we theoretically and experimentally construct a non-diffraction, partially coherent Pearcey beam. The results clearly demonstrate such a beam remains invariant during propagation under different coherence conditions. The experimental results align closely with the theoretical predictions. We believe that this beam has the potential to offer new insights as an information carrier for optical communication and information transmission, particularly in adverse environments.

Investigating the spatiotemporal distribution of refractivity structure index in low-speed flow field by moiré deflectometry

Abstract Atmospheric optical turbulence is a significant restraint on free-space optical communication and atmospheric laser transmission, whose intensity is generally quantified by the refractivity structure index. In this paper, moiré deflectometry is applied to study the combined effects of thermal disturbance and flow speed on the spatiotemporal distribution of the refractivity structure index. Firstly, three sets of comparative experiments are conducted, and 3600 frames of moiré fringes are captured within an hour in each set. Then, the spatiotemporal distribution is obtained based on the theoretical relationship between the refractivity structure index and the phase information recorded by moiré fringes. Finally, its regularities under different experimental conditions are comparatively analyzed. The findings reveal that both thermal disturbance and flow speed will change the intensity of optical turbulence. And, although the latter has a much weaker impact than the former, their combined effects will increase the intensity by three orders of magnitude. In this process, the contribution of thermal disturbance accounts for more than 75%. In short, the related results could provide some insights for research on atmospheric optical detection and communication.

Dual-channel asymmetric absorption-transmission properties based on plasma metastructures-photonic crystals.

In this paper, a kind of plasma metastructures-photonic crystals (PMPC) structure is proposed to investigate the absorption and transmission properties of electromagnetic waves (EWs) incident from opposite directions. The results show that the PMPC can achieve a dual-channel asymmetric absorption-transmission (AAT) phenomenon. At an operating bandwidth (OB) of 2.15∼2.85 GHz, EWs are absorbed in the forward incidence and transmitted in the backward case, and a relative bandwidth (RB) with forward absorption above 0.9 is 28.0%. On the contrary, at an OB of 7.07∼7.67 GHz, EWs can be transmitted in the forward propagation and absorbed in the backward case with a RB of 8.1%. Moreover, the effects of parameters such as applied magnetic field, incident angle, and tilt angle on AAT performance are investigated separately. The proposed dual-channel tunable AAT will further extend the application of asymmetric devices in the fields of optical communication and optical transmission.

1 × 4 Integrated Microlenses High-Rate Photodetector Array for Optical Communication Transmission

1 × 4 Integrated Microlenses High-Rate Photodetector Array for Optical Communication Transmission

PERFORMANCE ANALYSIS OF OPTICAL WIRELESS COMMUNICATION SYSTEM DESIGNED BY USING DIFFERENT FILTERS

Free space optical communication (FSO) technology, which has been developing in recent years, is advantageous compared to other wireless communication technologies due to its features such as high bandwidth, low latency, and high security. Since the FSO system is sensitive to atmospheric events, it needs various signal processing and filtering techniques to reduce the deterioration in the quality of the signal. The FSO free space channel has several channel types, such as the scattered channel and the optical wireless communication (OWC) channel. In this study, comparisons were made using various filters in an FSO system designed using the optical wireless communication (OWC) transmission channel model, and the system was analyzed based on the results obtained.

Diffraction-free distance enhancement of Bessel beams based on spatial domain phase modulation

Bessel beams have garnered significant interest due to their unique diffraction-free properties and extensive potential applications. In this work, we propose a spatial domain phase modulation theory to achieve diffraction-free distance enhancement of Bessel beams, overcoming the limitation of the traditional methods due to the inability to infinitely decrease the wave vector angle. The traditional formula for non-diffraction distance is also modified. Simulation results demonstrate that our proposed scheme can significantly increase the maximum diffraction-free distance of zero-order and higher-order Bessel beams by more than two times, while ensuring the self-healing property of Bessel beams. Furthermore, our proposed scheme is not restricted to specific systems or limited to the optical wavelength range. This implies that the results have great applicative potential in long-distance free-space optical communication and wireless energy transmission.

Research on Adaptive Reverse Design Method of Integrated Optical Fiber Communication System

The vigorous development of network technology promotes the progress of communication transmission technology, and the progress of communication transmission technology also drives the development of network technology. Optical fiber communication technology is widely used in communication industry because of its strong anti-interference ability, fast transmission speed and large amount of information. With the explosive growth of network data traffic in recent years, the transmission capacity of optical fiber communication has been continuously improved, coherent optical communication technology has developed rapidly, the trend of intelligence, grouping and broadband has become more and more obvious, and new photoelectric devices have been continuously developed and used. Optical fiber communication technology is undergoing tremendous changes and will become more important. In this paper, the application of optical fiber communication transmission technology is discussed in detail, and an adaptive reverse design method of integrated optical fiber communication system is proposed in order to promote the rapid development of optical fiber communication transmission technology.

Flexible generation of high-performance superposed perfect vortex beams with metasurfaces

Vortex beams have been adopted as optical communications tools to improve the information capacity of free-space communication. Topological charge (TC) is a key parameter for analyzing vortex beams, specifically when defining wavelength division multiplexing and information coding capabilities. TC is typically proportional to the radial intensity profile and orbital angular momentum. The radial intensity profile of perfect vortex (PV) beams is TC-independent, thereby improving the efficiency of image processing and optical fiber transmission; however, PV beams generated in traditional ways are restricted in their degree of freedom for multiplexing and it can be difficult to distinguish PV beams with different TCs. Herein, we numerically simulate a single all-dielectric geometric metasurface to generate PV beams with intensity patterns corresponding to the TC. We increase the types of intensity modes by superposing specific polarization states of Laguerre–Gaussian beams, creating many options for optical communication transmission purposes.

Retraction: A design of wet-mateable connector aiming for contactless power transfer and optical communication (IOP Conf. Ser.: Earth Environ. Sci. 1152 012016)

This article has been retracted by IOP Publishing following the discovery that large sections of it were duplicated from another paper [1] written by the authors that was submitted to another publisher in parallel and published prior to this article. The authors initially requested a retraction, but failed to provide necessary information and then withdrew the retraction request. The authors have now confirmed that redundant publication has occurred. This matter was investigated in line with COPE guidelines and IOP Publishing has decided to retract the work. The authors agree to this retraction. [1] Duan, Z., Zhang, Y., Hu, J., He, B., & Yang, C. (2023). Research on non-contact wet mateable connector for optical communication and power transmission. Retrieved from https://www.frontiersin.org/articles/10.3389/fmars.2023.1100653/full Retraction published: 27 July 2023

Research on non-contact wet mateable connector for optical communication and power transmission

At present, contact watertight connectors are commonly utilized for the connection between underwater electromechanical equipment and the seabed observation network. Such traditional watertight connectors are easy to be irreversibly worn when plugging and unplugging, however, they have complicated sealing structures and limited service life. This paper designs a Non-contact Wet Mateable connector for Optical Communication and Power Transmission (OCPT-NWMC), which is based on technology of Contactless Power Transmission (CLPT) and optical communication. Docking structure of the sockets and plugs are designed, facilitating Remotely Operated Vehicle (ROV) to operate. A prototype of the OCPT-NWMC was established. The experimental results show that the connector designed can achieve 200W power transmission, with a maximum power transmission efficiency of 94%. The communication bandwidth reaches 18MHz. The OCPT-NWMC can assist the rapid and safe deployment and operation of seabed observation network.

Research on Pulse Power Wireless Communication Network Based on LoRa Technology

In this paper, the engineering of pulse power supply in electromagnetic launch technology is studied in depth, the advantages and disadvantages of optical fiber communication transmission currently used are analyzed, and then the requirements for data transmission of pulse power supply system are summarized, and several commonly used wireless communication technologies are analyzed and compared, such as ZigBee, LoRa, SigFox, NB IoT, 5G, etc. According to the comprehensive comparison of these technologies in transmission distance, rate, bandwidth, security, time delay, self built network and other aspects, the scheme of using LoRa wireless communication technology to replace optical fiber transmission is finally determined, and the LoRa wireless communication network construction, controller hardware circuit design, module software program, data transmission communication protocol, data encryption, data storage and other contents in the scheme are further designed in detail, It also predicts the further research and development of LoRa wireless communication technology in pulse power supply.

Performance Analysis of Mixed PLC-FSO Dual-Hop Communication Systems

In this article, we analyze the performance of a mixed dual-hop power line communication/free-space optical communication (PLC-FSO) transmission system supporting both decode-and-forward (DF) and fixed-gain amplify-and-forward (AF) relaying protocols. Further, it is assumed that the PLC link experiences log-normal fading under the effects of additive background and impulsive noise, while the free-space optical (FSO) channel obeys an exponentiated Weibull distribution with pointing errors. On this basis, we derive the probability density function (PDF) and cumulative distribution function (CDF) of the end-to-end (e2e) signal-to-noise ratio (SNR). To evaluate the system performance, the closed-form expressions for the outage probability (OP) and average bit-error rate (BER) are derived. Additionally, to gain more insights, the asymptotic analysis of OP and average BER, and the upper bound of the average capacity are presented.

Information Steganography Technology of Optical Communication Sensor Network Based on Virtual Reality Technology

In order to solve the problems of narrow object orientation and insufficient visual rendering ability of the optical communication network experimental system, the author proposes a multithreaded scheduling using virtual reality, and the experimental system design method of optical communication network with multichannel serial port design is proposed. The system builds the overall structure model of the optical communication network experimental system in the virtual reality environment, and uses the PCI bus technology to build the transmission channel model of the optical communication network, the basic entity object of the optical communication network experimental system is constructed, and the multithread scheduling method is used to process the local information of the experimental system. The result obtained is as follows: The experimental system of optical communication network designed by the author’s method, the optical communication transmission bit error rate is reduced by about 30%, the time overhead is saved by about 60%, and the memory overhead is saved by about 50%, which is superior. Using the author’s method, the maximum bit error rate is about 22%, while the maximum bit error rate of traditional method 1 is about 43%, and the maximum bit error rate of traditional method 2 is about 70%. It is proven that the visual simulation effect of the optical communication network experimental system is good, the reliability and stability of the optical communication network are improved, and the communication transmission error is reduced.

130-m Image sensor based Visible Light Communication (VLC) using under-sample modulation and spatial modulation

Visible light communication (VLC) allows low-cost, simple and flexible optical wireless communication (OWC) transmission. In this work, we put forward and demonstrate for the first time 100 m non-flickering image sensor based VLC using under-sampled phase shift on-off keying (UPSOOK) and 6-bit 4-light-emitting-diode (LED) spatial modulation. As each light emitting diode (LED) can provide three well distinguished intensity states, 6-bit data can be realized by using only 4 LEDs in the vehicle rear lamps. Bit-error-rate (BER) measurements at different camera ISO values are also studies. Experimental results show that 130 m long distance 120 bit/s image sensor based VLC system can be achieved using a single white-LED at ISO = 800. Results also show that 100 m long distance 720 bit/s image sensor based VLC system can be realized using 4 LEDs at ISO = 800. Both results satisfy the pre-forward error correction BER (pre-FEC, BER = 3.8 × 10−3).

Performance of Non-Line of Sight Underwater Optical Wireless Communication Links with Spatial Diversity

Line-of-sight (LOS) underwater optical wireless communication (UOWC) transmission may suffer blocking and are not always possible due to obstructions from sea creatures, bubbles, large suspended particles and features of the seabed, especially in coastal and turbid water environments. Thus, we present the performance of a spatially diverse non-line-of-sight (NLOS) UOWC system employing continuous phase modulation (CPM), which is shown to offer sensitivity benefits of several dBs over on–off keying (OOK) without coherent reception. We obtain the channel impulse response (CIR) by using Monte Carlo simulation, including absorption and multiple scattering. Turbulence is included by conditioning the CIR on log-normal statistics. To mitigate the resultant fading, we exploit spatial diversity with equal gain combining at the receiver side. Photon counting at the receiver is employed to accommodate shot noise. We compare the saddlepoint and Gaussian approximations for bit error rate (BER) calculations, using the latter for later calculations as it delivers excellent results and is simpler. Our results show that spatial diversity offers performance improvements, for example an 8 dB sensitivity gain at 10^-9 BER using 1 Gbps 3×1 multiple-input single-output (MISO) transmission over a 20 m link with 0.16 log-amplitude variance. We determine using an upper bound that Intersymbol Interference (ISI) has a significant impact at high bit rates, producing error floors for multiple-output arrangements.

Performances enhancement of underwater wireless optical communications (UWOC) using pulse position modulation

Abstract In this work, we study the performance analysis of underwater optical wireless communication (UOWC) transmission link by incorporating optical code division multiple access (OCDMA) using pulse position modulation (PPM) to enhance the channel range and cardinality. Bit error rate (BER) variations are examined versus the range, modulation type (on–off keying (OOK), quadrature amplitude modulation (QAM), etc.), number of users as well as the channel attenuation caused by different water types. The power and transmitter inclination angle limitation, of the enhanced system, are also presented in order to determine the threshold for which the minimum BER 10−9 is achievable.

Flexible High‐Stability Self‐Variable‐Voltage Monolithic Integrated System Achieved by High‐Brightness LED for Information Transmission (Small 45/2021)

Light Information Transmission A high performance self-variable-voltage light information transmission integrated system is reported in article number 2105207 by Jing Ning, Jincheng Zhang, and co-workers and its application potential in low-power, self-powered optical communication transmission systems is demonstrated. The diffusion adsorption regulation growth method and laser induction technology are proposed to realize high-brightness LED and flexible micro-supercapacitor on graphene. This study will provide a new approach to realize low-power optical communication transmission systems.

Flexible High-Stability Self-Variable-Voltage Monolithic Integrated System Achieved by High-Brightness LED for Information Transmission.

The emergence of visible light information transmission systems is profoundly affecting the future of the Internet of Things (IoT) technology. The complex sensing and driving circuits of the IoT have become the key factor to hinder signal conversion and processing. Herein, a high-performance self-variable-voltage light information transmission integrated system (SVV-LTS) is reported and its application potential in low-power, self-powered optical communication transmission systems is demonstrated. Diffusion-adsorption regulation growth method and laser induction technology are innovatively used to realize high-brightness light-emitting diode (LED) and flexible micro-supercapacitor (MSC) on graphene. Meanwhile, MSC realizes the dual functions of supplying power to the system, realizing pressure signal response, and converting pressure signals into electrical signals. Finally, the MSC as power, sensor and LED as signal transmitter are integrated into an SVV-LTS. The response time of SVV-LTS is 80ms and the luminous wavelength fluctuation of the LED is stable at 1.2nm. This study will provide a new approach to realize low-power optical communication transmission systems affecting the IoT technology.

Implementation of a fiber-based resonant beam system for multiuser optical wireless information and power transfer

A fiber-based resonant beam system is proposed for a simultaneous optical wireless information and power transfer (OWIPT) system. A fiber Bragg grating and an optical circulator are used to achieve simultaneous wireless optical communication and power transmission. In the receiver subsystem, a communication and energy harvesting circuit is employed to separate alternating current (AC) and direct current (DC) outputs. The AC output is used for information transmission, and the DC output is used for power transfer. We conducted experiments to test the built-in safety mechanism to verify whether the resonant beam stops immediately if any obstacle obstructs the line of sight of the system. The proposed architecture can be constructed for indoor and outdoor multiuser applications. The results demonstrated that the proposed fiber-based resonant beam system can be implemented successfully for simultaneous OWIPT.