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- 摘要
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Wide Field-of-View Transceiver Design for Bidirectional Free-space Optical Communication Systems
摘要： We propose an optical transceiver utilizing fiber bundle to have a large field-of-view for free-space optics applications. Our proof-of-concept experiment shows that the 7-fiber bundle provides 4-fold improvement in tolerance to angle-of-arrival fluctuations.
关键词： Free-space optics or optical micro-electro-mechanical system (MEMS) for photonic networks,Optical transmitter and receiver subsystems
更新于2025-09-16 10:30:52
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Optical Fiber Communications (Principles and Applications) || Wireless Optics
摘要： The wireless optics holds great potential for fixed wireless communications as well as for other wireless applications. In spite of all other technology developments, wireless optics has promised an economical alternative to last mile connection solution in the wireless domain. The concept of wireless optics was originally developed over few decades ago by the military. An optical wireless technology, also known as free space optics (FSO) technology, provides broadband data communication links between line-of-sight (point-to-point) locations.
关键词： FSO,wireless optics,free space optics,broadband,line-of-sight
更新于2025-09-12 10:27:22
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[IEEE 2018 International Topical Meeting on Microwave Photonics (MWP) - Toulouse (2018.10.22-2018.10.25)] 2018 International Topical Meeting on Microwave Photonics (MWP) - Spatial Diversity Gain of Micrometer-scale MIMO FSO Transceivers utilizing Multicore Fiber and 2-D Photodetector Array
摘要： Feasibility of a high-capacity spatially-multiplexed free-space optical (FSO) communications system utilizing small-footprint spatial diversity transceivers based on multicore fiber and 2-D photodetector array is investigated. With the aid of MIMO-DSP, the micrometer-scale spatial diversity transceivers enable 37-Gbps 2x4 MIMO-FSO transmission over strongly-correlated optical MIMO channels.
关键词： Free space optics MIMO,Space-division multiplexing,Spatial diversity,Optical wireless communication
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE 16th International Conference on Smart Cities: Improving Quality of Life Using ICT & IoT and AI (HONET-ICT) - Charlotte, NC, USA (2019.10.6-2019.10.9)] 2019 IEEE 16th International Conference on Smart Cities: Improving Quality of Life Using ICT & IoT and AI (HONET-ICT) - Review of Studies that Integrate the Free Space Optics with Fiber Optics
摘要： This paper presents a comprehensive survey on the importance of free space optics (FSO) systems used as last mile for communication systems and their integration with optical fibers. Optical fiber is already being used in the backbone networks due to its high speed and high bandwidth qualities but the last mile has always been a problem. Last mile is the last physical connection between access network and the end user. FSO systems provide an innovative solution to this problem. The surveyed integration techniques are explained with their working principles. All the nodes used to make this integration possible are also thoroughly explained. The advantages and disadvantages of FSO systems are also listed and discussed. The paper also discusses current challenges and directions for future research.
关键词： Free space optics,Wireless networks,Access network,Fiber optics
更新于2025-09-11 14:15:04
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Efficient Optical Alignment Technique for Compact 100 and 400 GbE TOSAs with Integrated Multiplexing with Free Space Optics
摘要： An efficient and low-cost optical alignment technique is for the first time established for compact transmitter optical sub-assemblies (TOSAs) with an integrated multiplexer based on free space optics (FSO) for 100 and 400 Gbps Ethernet (GbE) applications. A compact FSO system for the 100 GbE TOSA is fabricated in a compact package 6.5 mm × 15.1 mm × 5.6 mm in size to confirm the validity of the technique. It is demonstrated by experiment that the optimum optical alignment condition can successfully be figured out by this technique without any expensive equipment, which has been a significant issue for TOSAs with integrated FSO systems, confirming the validity of the technique. Further, Monte Carlo simulations show that the optical output power distribution across the lanes is compatible with the 100 GbE LR4 specification, indicating the suitability of the proposed low-cost alignment technique. It is also shown that the acceptable long-term power variation required for reliability is predicted owing to the relaxation of the positional tolerance of the collimator lenses, which is obtained by the proposed technique. Finally the feasibility of the technique is discussed for 400 GbE TOSAs with eight-lane optical systems.
关键词： transmitter optical sub-assembly (TOSA),laser diode (LD),100 and 400 Gbps Ethernet (GbE),Free space optics (FSO),hybrid integration
更新于2025-09-10 09:29:36
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High-Speed Reconfigurable Free-Space Optical Interconnects with Carrierless-Amplitude-Phase Modulation and Space-Time-Block Code
摘要： High-speed interconnects are highly demanded in data centers and high-performance computing, and the use of optical interconnects to replace electrical interconnects has been proposed and widely studied. For medium-range board-to-board communications, free-space based optical interconnects provide the additional advantage of reconfigurability and flexibility, compared with traditional waveguide or fiber based counterparts. However, the bit rate and interconnection range in free-space optical interconnects are typically limited. In this paper, we propose a carrierless-amplitude-phase (CAP) modulated and space-time coded free-space optical interconnect scheme to overcome these limitations. Up to 80 Gb/s (2×40 Gb/s) interconnection with reconfigurability and flexibility is experimentally demonstrated for a maximum error-free distance exceeding 50 cm, showing about 65% improvement over previous demonstrations. The receiver sensitivity of the space-time coded system is measured as well, and results show that the space-time-block code (STBC) is capable of improving the receiver sensitivity and suppressing the inter-channel crosstalk. The impact of air turbulence, which exists in typical interconnect environments, is also experimentally investigated and results show that its impact on the proposed scheme is negligible. The proposed reconfigurable free-space optical interconnects with CAP and STBC can be further scaled up to provide higher speed and further extended interconnection range.
关键词： free-space optics,carrierless-amplitude-phase modulation,air turbulence,space-time-block-code,Optical interconnects
更新于2025-09-09 09:28:46
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Network Topology Reconfiguration for FSO-based Fronthaul/Backhaul in 5G+ Wireless Networks
摘要： Using free space optics (FSO) in the mobile fronthaul/backhaul networks is a promising solution that can potentially enhance the capacity of mobile networks. The main challenge of establishing FSO-based fronthaul/backhaul networks is the dynamic feature of the networks, i.e., the fragile links under adverse weather conditions and the dynamic traf?c demands among small cells. Topology recon?guration is proposed to dynamically rearrange the FSO links. In this paper, two types of network recon?gurations are investigated, in which the proactive network recon?guration is to proactively optimize the topology of the FSO-based fronthaul/ backhaul networks for each speci?c time period based on the statistics of the network, and the reactive recon?guration is to actively adjust the topology when traf?c demands and link states are changed. The proactive network recon?guration is formulated as a mixed integer nonlinear programming (MINLP) problem, which jointly optimizes the network throughput and power consumption of FSO-based fronthaul/backhaul networks. A greedy algorithm is proposed to derive the solution of the proposed problem. After the network topology having been recon?gured by solving the MINLP problem, two reactive recon?guration algorithms are designed to optimally adjust the network topology once a link failure and demand explosion occur, respectively, to further enhance the network throughput and reduce the power consumption. The performance of the algorithms is demonstrated via extensive simulations.
关键词： FSO-based fronthaul/backhaul,multi-criteria optimization,topology recon?guration,free space optics (FSO)
更新于2025-09-09 09:28:46
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An optimization model for robust FSO network dimensioning
摘要： FSO (Free Space Optics) is a well established wireless optical transmission technology considered as an alternative to radio communications, for example in metropolitan wireless mesh networks. An FSO link is established by means of a laser beam connecting the transmitter and the receiver placed in the line of sight. A major disadvantage of FSO links (with respect to fiber links) is their sensitivity to weather conditions such as fog, rain and snow, causing substantial loss of the transmission power over the optical channel due mostly to absorption and scattering. Thus, although the FSO technology allows for fast and low-cost deployment of broadband networks, its operation will be affected by this sensitivity, manifested by substantial losses in links’ transmission capacity with respect to the nominal capacity. Therefore, a proper approach to FSO network dimensioning should take such losses into account so that the level of carried traffic is satisfactory under all observed weather conditions. In the paper we describe such an approach. We introduce a relevant dimensioning problem and present a robust optimization algorithm for such enhanced dimensioning. A substantial part of the paper is devoted to present a numerical study of two FSO network instances that illustrates the promising effectiveness of the proposed approach.
关键词： Free space optics,Multicommodity flows,Linear and mixed-integer programming,Robust optimization,Resilient and survivable networks,Variable link capacity
更新于2025-09-09 09:28:46
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Performance Analysis of Hybrid RF/FSO System using BPSK-SIM and DPSK-SIM over Gamma-Gamma Turbulence Channel with Pointing errors for Smart City Applications
摘要： The in wireless communication -Free space optics (FSO) offers lots of merits over radio frequency (RF) links due to its license free bandwidth, ease of installation, high security features, and viable cost for short distance communication. It's high speed data rate and immunity against Electromagnetic Interference (EMI) makes FSO the emerging technology of today. But, FSO is not always reliable especially during Atmospheric conditions like fog, rain, mist and snow. Hence, in account a new technique of Hybrid FSO/RF, this includes advantages of both FSO and RF technologies. Through this paper intend to perform an extensive analysis of the error and misalignment effects encountered in Line Of Sight (LOS) communication. Pointing error and turbulence effects are the main drawback parameters for our analysis. For this purpose I have taken into consideration different modulation techniques-Binary Phase Shift keying-Subcarrier Intensity Modulation (BPSK-SIM), Differential Phase Shift Keying- Subcarrier Intensity Modulation (DPSK-SIM) communication system with reference to OOK Modulation. The novel expressions for outage probability and BER for both FSO and RF system are derived which uses Rician Channel and 16QAM Modulation scheme alongside Hybrid FSO/RF system for weak, moderate, strong turbulence regimes using Meijer-G Function.
关键词： Free space optics,Hybrid RF/FSO,Gamma-Gamma Channel,Atmospheric turbulence
更新于2025-09-04 15:30:14