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- 摘要
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Towards Energy Neutral Wireless Communications: Photovoltaic Cells to Connect Remote Areas
摘要： In this work, we have designed, developed and deployed the world’s first optical wireless communication (OWC) system using off-the-shelf lasers and solar photovoltaics. Four bidirectional OWC prototypes have been installed on the Orkney Islands of Scotland at a 30 m link distance for the provision of high-speed internet access to two residential properties. The silicon-made solar panels can harvest power up to 5 W from sunlight and they offer data rates as high as 8 Mb/s. Using additional analogue processing, data rates higher than the existing landline broadband connection are achieved. This breakthrough opens the development path to low cost, self-powered and plug-and-play free-space optical (FSO) systems.
关键词： communication systems,free-space optical communication,light communication,solar energy,optical wireless communications,energy harvesting
更新于2025-09-16 10:30:52
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On-chip integrated optical switch based on polymer waveguides
摘要： Optical polymer is one of the promising materials for photonic integrated devices that can be processed with simple, flexible and semiconductor compatible technology. Especially, optical polymer with the advantages of high thermo-optic (TO) and electro-optic (EO) coefficients has been widely applied in optical waveguide switches. However, most of the current optical switches are independent with single function. It is essential to develop an on-chip integrated device with multilayer for signal manipulation. In this paper, we propose an on-chip 3-dimensional integrated optical switch based on the EO polymer-clad waveguide incorporate with the TO tunable vertical coupler. The proposed integrated optical switch could realize the function-integration of the adjustable 3D optical connection and the high-speed modulation. A typical fabricated switch shows an insertion loss of 16.3 dB and an extinction ratio of 16.0 dB at the driving power of 48.2 mW. The dynamic characteristics of TO and EO switching functions of the device were also measured in this work.
关键词： Polymer waveguide,Thermo-optic effect,Electro-optic effect,Optical communication,Optical switch
更新于2025-09-16 10:30:52
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Performance of grey-coded IQM-based optical modulation formats on high-speed long-haul optical communication link
摘要： In this article the performance of grey-coded advanced optical modulation formats is evaluated on a single-channel high-speed long-haul optical communication link and are compared to the respective differential-coded modulation formats. Polarisation division multiplexed optical in-phase quadrature modulator (IQM) structure and homodyne detection scheme are used to realise 100 Gbps quadrature phase-shift keying (QPSK), 120 Gbps 16-ary quadrature amplitude modulation (16-QAM), 360 Gbps 32-QAM and 480 Gbps 64-QAM modulation formats. Advanced digital signal processing unit with various pre-processing and recovery stages such as direct current blocking, normalisation, low-pass Bessel filter, resampling, quadrature imbalance compensation, chromatic dispersion compensation, non-linear compensation, timing recovery, adaptive equalisation, down-sampling, frequency offset estimation, and carrier phase estimation is used at the receiving end to compensate for signal impairments during propagation. Maximum transmission distances of 7200, 1050, 560, and 360 km have been achieved at an acceptable bit error rate for QPSK, 16-QAM, 32-QAM, and 64-QAM, respectively. The grey-coded systems outperformed the differential-coded systems regarding optical signal-to-noise ratio requirement, receiver sensitivity, and transmission distance.
关键词： grey-coded,optical modulation formats,high-speed long-haul optical communication,homodyne detection,IQM,digital signal processing
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - A Compact Circuit Model for Si-Ge Avalanche Photodiodes over a Wide Range of Gain
摘要： A Si-Ge avalanche photodiode circuit model is demonstrated, which includes carrier transit time, avalanche buildup time, and electrical parasitics. Electrical and optical dynamics are accurately captured over a wide range of gain. Excellent matching between simulated and measured 50 Gb/s PAM4 eye diagrams is achieved.
关键词： Avalanche photodiodes (APDs),Optical communication,Modeling
更新于2025-09-16 10:30:52
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Joint equalization of linear impairments using two-stage cascade Kalman filter structure in coherent optical communication systems
摘要： In this paper, instead of adopting different algorithms to deal with the different impairments separately based on different signal processing structures, we proposed a joint linear impairment equalization scheme using a two-stage cascade Kalman structure in which the first stage solves the residual chromatic dispersion (rCD), the rotation of state of polarization (RSOP) and polarization mode dispersion (PMD), and the second stage compensates for the carrier frequency offset (CFO) and carrier phase noise (CPN). The structures of the two stages are similar with a seamless connection and possess a clear logic architecture. The stages are compatible with each other and achieve excellent performance. We aim to use this two-stage Kalman scheme as a comprehensive DSP equalization scheme to replace the combined algorithms of the constant modulus algorithm (CMA), improved Mth-power algorithm (IMP), and blind phase search (BPS). Simulations based on a 28 Gbaud polarization division multiplexed quadrature-phase shift keying coherent optical communication system show that the proposed two-stage Kalman scheme comprehensively outperforms the CMA-IMP-BPS scheme in solving the problems of RSOP, PMD, rCD, CFO, and CPN. The experimental results confirm the simulation results. In addition, the complexity of the proposed Kalman scheme is relatively less than the CMA-IMP-BPS scheme.
关键词： Polarization,Extend Kalman filter,Residual CD,Coherent optical communication,Carrier phase
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Large-scale arrayed waveguide grating router for T-band communication
摘要： bandwidth was more than 100 nm, and whole T-band can be covered by three different gain chips. The gain chip has high power output up to 190 mW with an injection current of 800 mA as shown in Fig. 3. It can be operated more than 95 ℃. The estimated life is longer than 106 hours. SOA modules were fabricated using QD gain chips. The T-band (1000-1260 nm), which offers more than 60 THz worth of bandwidth and wider than C- and L-band combined. The large scale photonic router using 3-stage arrayed-waveguide grating for T-band and O-band is configured.
关键词： quantum dot laser,optical communication,arrayed waveguide grating,T-band,AWGR
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Experimental demonstration of atmospheric channel reciprocity in fiber receiving systems
摘要： This paper designs a reciprocity measurement system for atmospheric channel for the first time in China. The mean of reciprocity is higher than 0.8, which proves that the atmospheric channel has strong reciprocity. The research in this paper provides a parameter reference for adaptive optics system design.
关键词： Atmospheric turbulence,Optical Communication,Adaptive optics
更新于2025-09-16 10:30:52
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A Review on Practical Considerations and Solutions in Underwater Wireless Optical Communication
摘要： Underwater wireless optical communication (UWOC) has attracted increasing interest in various underwater activities because of its order-of-magnitude higher bandwidth compared to acoustic and radio-frequency technologies. Testbeds and pre-aligned UWOC links were constructed for physical layer evaluation, which verified that UWOC systems can operate at tens of gigabits per second or close to a hundred meters of distance. This holds promise for realizing a globally connected Internet of Underwater Things (IoUT). However, due to the fundamental complexity of the ocean water environment, there are considerable practical challenges in establishing reliable UWOC links. Thus, in addition to providing an exhaustive overview of recent advances in UWOC, this paper addresses various underwater challenges and offers insights into the solutions for these challenges. In particular, oceanic turbulence, which induces scintillation and misalignment in underwater links, is one key factor in degrading UWOC performance. Novel solutions are proposed to ease the requirements on pointing, acquisition, and tracking (PAT) for establishing robustness in UWOC links. The solutions include light-scattering-based non-line-of-sight (NLOS) PAT-relieving communication modality as well as scintillating-fiber-based photoreceiver and large-photovoltaic cells as the optical signal detectors. Naturally, the dual-function photovoltaic–photodetector device readily offers a means of energy harvesting for powering up future IoUT sensors.
关键词： non-line-of-sight,Underwater wireless optical communication,energy harvesting,turbulence,fiber detector
更新于2025-09-16 10:30:52
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Deep-Space Optical Communication Link Engineering: Sensitivity Analysis
摘要： Science and exploration missions are continuously enlarging the science volume generated onboard the spacecraft, limited typically by the capabilities of the communication link. Although the rather unexploited Ka-band allocation around 32 GHz provides some relief in this respect [1], particularly if used with large size high gain antennas, optical communications bear the promise of delivering higher data rates in the mid-term [2]. For setting the scene for the optical communications technology, it is always interesting to understand where the limits are of current RF-based deep-space systems. Toward this, [3] is extrapolating the performance of Payload Data Transmitters from the current state-of-the-art to the 2023 technology time frame (see Table 1). Coming now to the technology which is the scope of this paper, for deep-space optical communications, the space agencies in Consultative Committee for Space Data Systems (CCSDS) recently concluded on a standard for high photon efficiency (HPE). The standard comprises a specification on the coding and synchronization layer [4] and one on the physical layer [5]. After specifying the standard, space agencies are now focused on planning in orbit demonstrations (IOD), although the waveform of [4] was already demonstrated to laser a frame of in the extent lunar large the Authors’ current addresses: N. K. Lyras, School of Electrical and Computer Engineering, National Technical University of Athens, Athens 15780, Greece. A. D. Panagopoulos, School of Electrical and Computer Engineering, National Technical University of Athens, Athens 15780, Greece, E-mail: (thpanag@ece.ntua.gr). P.-D. Arapoglou, European Space Agency/ESTEC, Noordwijk 2200, The Netherlands. Manuscript received January 15, 2019, revised July 5, 2019, and ready for publication September 24, 2019. Review handled by Prof. Mauro De Sanctis. 0885-8985/19/$26.00 (cid:1) 2019 IEEE communication demonstration [6]. From the European Space Agency point of view, a deep-space optical communication system IOD opportunity could be the space safety program, space weather mission to the Sun–Earth Lagrange point L5 [7]. In this paper, a tool is presented for aiding such IOD missions fully relying on the CCSDS HPE. The main elements that must be taken into account in a deep-space link budget analysis are summarized in Figure 1. The main assumptions of the work involve an optical downlink operating under cloud-free line of sight (CFLOS) conditions [8], [9] between an optical terminal onboard a deep-space spacecraft and an optical ground station. A Poisson is representative of deep-space optical channel model links. Due to the power limited nature of these links intensity modulation (IM) and direct detection (DD) with photon-counting detectors the transmitter and receiver architecture, respectively. Under these conditions, the pulse position modulation (PPM) signaling [11] and a serially concatenated pulse position modulation (SCPPM) [12] are capacity achieving. [10] are considered for Apart from performing a sensitivity analysis of various hypothetical deep-space missions, the paper presents a practical methodology that allows the link designer to select the main signaling parameters (modulation order, code rate, slot width), without resorting to lengthy coded bit error rate (BER) evaluations that otherwise need to be run for a large parameter set. This allows faster link budget calculations, e.g., for performing trade-off studies.
关键词： sensitivity analysis,deep-space optical communication,CCSDS HPE,link budget,photon-counting detectors
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Fiber Nonlinearity Equalizer using MLP-ANN for Coherent Optical OFDM
摘要： We propose a novel artificial neural network nonlinearity equalizer based on multiple layers perceptron(MLP-ANN NLE) for16-quadrature amplitude modulation (16-QAM) coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. The scheme is effective for compensating for the four-wave mixing effect among subcarriers. Compared with the situation of non-compensated nonlinearity, this proposed scheme can increase the Q factor by 1.4 dB and 0.6 dB at 600 km and 2000 km respectively and the transmission distance can be increased by 400 km. It also shows a strong robustness in nonlinearity compensation.
关键词： OFDM,Fiber optical communication,Nonlinearity effect
更新于2025-09-16 10:30:52