A5017330036- Optical Network Technologies
- Advanced Photonic Communication Systems
- Advanced Wireless Communication Techniques
- Advanced Optical Network Technologies
- Error Correcting Code Techniques
- graph theory and CDMA systems
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Advanced Fiber Laser Technologies
- Optical Wireless Communication Technologies
- Coding theory and cryptography
- Advanced Data Compression Techniques
- Blind Source Separation Techniques
- PAPR reduction in OFDM
- Algorithms and Data Compression
- Advanced Fiber Optic Sensors
- Neural Networks and Reservoir Computing
- Wireless Communication Networks Research
- Mathematical Analysis and Transform Methods
- Cellular Automata and Applications
- Photonic Crystal and Fiber Optics
- Medical Imaging Techniques and Applications
- Wireless Communication Security Techniques
- Interconnection Networks and Systems
- Image and Signal Denoising Methods
Chalmers University of Technology
2016-2025
Max Planck Institute for Gravitational Physics
2022-2025
Leibniz University Hannover
2022
Mitsubishi Electric (Japan)
2020
Osaka University
2020
Institute of Electrical and Electronics Engineers
2016-2019
University of Arizona
2018
Optica
2018
Eindhoven University of Technology
2016
University College London
2015-2016
In this semitutorial paper, a comprehensive survey of closest point search methods for lattices without regular structure is presented. The existing strategies are described in unified framework, and differences between them elucidated. An efficient algorithm, based on the Schnorr-Euchner (1995) variation Pohst (1981) method, implemented. Given an arbitrary x /spl isin/ Ropf//sup m/ generator matrix lattice Lambda/, algorithm computes Lambda/ that to x. shown be substantially faster than...
Quantum Communication is the art of transferring an unknown quantum state from one location, Alice, to a distant one, Bob. This non-trivial task because no-cloning theorem which prevents merely using only classical means.
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Coherent optical transmission systems have a four-dimensional (4–D) signal space (two quadratures in two polarizations). These four dimensions can be used to create modulation formats that better power efficiency (higher sensitivity) than the conventional binary phase shift keying/quadrature keying (BPSK/QPSK) signals. Several examples are given, with some emphasis on 24-level format and an...
The FEC limit paradigm is the prevalent practice for designing optical communication systems to attain a certain bit error rate (BER) without forward correction (FEC). This assumes that there an code will reduce BER after decoding desired level. In this paper, we challenge and show concept of channel-independent invalid soft-decision bit-wise decoding. It shown low rates high-order modulation formats, use can underestimate spectral efficiencies by up 20%. A better predictor generalized...
The FEC limit paradigm is the prevalent practice for designing optical communication systems to attain a certain bit error rate (BER) without forward correction (FEC). This assumes that there an code will reduce BER after decoding desired level. In this paper, we challenge and show concept of channel-independent invalid soft-decision bit-wise decoding. It shown low rates high-order modulation formats, use can underestimate spectral efficiencies by up 20%. A better predictor generalized...
By exploiting the electromagnetic wave's four-dimensional signal space, we find that for additive white Gaussian noise channel, modulation format with best sensitivity to be an 8-level 1.76 dB asymptotic gain over BPSK, uncoded optical transmission coherent detection.Low-complexity modulators are presented format, as well interpretation in terms of quantum-limited sensitivity.
In this work, we compare 4-pulse amplitude modulation and on–off keying formats at high speed for short-range optical communication systems. The transmission system comprised a directly modulated vertical-cavity surface-emitting laser operating wavelength of 850 nm, an OM3+ multimode fiber link, photodetector detecting the intensity receiver end. were compared both same bit-rate symbol rate. maximum used was 25 Gbps. Propagation distances up to 600 m investigated 12.5 All measurements done...
A low-complexity model for signal quality prediction in a nonlinear fiber-optical network is developed. The model, which builds on the Gaussian noise takes into account degradation caused by combination of chromatic dispersion, distortion, and amplifier noise. center frequencies, bandwidths, transmit powers can be chosen independently each channel, makes suitable analysis optimization resource allocation, routing, scheduling large-scale optical networks applying flexible-grid...
The implementation difficulties of combining distribution matching (DM) and dematching (invDM) for probabilistic shaping (PS) with soft-decision forward error correction (FEC) coding can be relaxed by reverse concatenation, which the FEC decoding lies inside algorithms. PS seemingly achieve performance close to Shannon limit, although there are practical challenges that need carefully addressed. We propose a hierarchical DM (HiDM) scheme, having fully parallelized input-output interfaces...
Abstract The Covid-19 pandemic showed forcefully the fundamental importance broadband data communication and internet has in our society. Optical communications forms undisputable backbone of this critical infrastructure, it is supported by an interdisciplinary research community striving to improve develop further. Since first ‘Roadmap optical communications’ was published 2016, field seen significant progress all areas, time ripe for update status. area become increasingly diverse,...
Let A(n,d,w) denote the maximum possible number of codewords in an (n,d,w) constant-weight binary code. We improve upon best known upper bounds on numerous instances for n/spl les/24 and d/spl les/12, which is parameter range existing tables. Most improvements occur d=8, 10, where we reduce more than half unresolved cases. also extend tables up to les/28 les/14. To obtain these results, develop new techniques introduce classes codes. derive a general by means mapping codes into Euclidean...
This paper concerns the problem of selecting a binary labeling for signal constellation in M-PSK, M-PAM, and M-QAM communication systems. Gray labelings are discussed original work by Frank is analyzed. As noted, number distinct that result different bit-error probability grows rapidly with increasing size. By introducing recursive construction method called expansion, answers natural question what labeling, among all possible labelings, will give lowest average bit errors considered...
This paper studies the routing, modulation format, and spectrum allocation problem in elastic fiber-optical networks for static traffic. Elastic networks, based on Nyquist wavelength-division multiplexing or optical orthogonal frequency-division multiplexing, can efficiently utilize fiber's bandwidth an manner by partitioning into hundreds even thousands of subcarriers. Beside amplified spontaneous emission noise, nonlinear impairments each connection is explicitly considered utilizing...
We experimentally investigate high-capacity few-mode fiber transmission for short and medium-haul optical links. In separate experiments, we demonstrate C + L band of 283 Tbit/s over a single 30 km span recirculating loop 159 1045 graded-index three mode fiber. The first experiment reached data-rate per within 90% the record data-rates reported in same bands single-mode fibers. second demonstrated feasibility reaching high long distance transmission, despite strong impairments due to...
We discuss optical transmission using homogeneous, single-mode, multicore fibers. first describe the key fiber properties that can affect transmission, such as intercore crosstalk and variation of propagation delay between cores, consequences these on spatial super-channel transmission. then a series experiments demonstrations system features including self-homodyne detection joint superchannel modulation before discussing their suitability to high-capacity
Asymptotic expressions of the mutual information between any discrete input and corresponding output scalar additive white Gaussian noise channel are presented in limit as signal-to-noise ratio (SNR) tends to infinity. symbol-error probability (SEP) minimum mean-square error (MMSE) achieved by estimating given also developed. It is shown that for distribution, conditional entropy output, MMSE SEP have an asymptotic behavior proportional Q-function. The argument Q-function depends only on...
Fundamental information-theoretic concepts are explained for nonspecialists, with emphasis on their practical usage. The notions of a "FEC threshold" and "nonlinear Shannon limit" critically reviewed, highlighting limitations possible alternatives.
With the continuously growing popularity of cloud services, traffic volume inside data centers is dramatically increasing. As a result, scalable and efficient infrastructure for center networks (DCNs) required. The current optical DCNs using either individual fibers or fiber ribbons are costly, bulky, hard to manage, not scalable. Spatial division multiplexing (SDM) based on multicore multimode (few-mode) recognized as promising technology increase spatial efficiency DCNs, which opens new...
Rate-adaptive optical transceivers can play an important role in exploiting the available resources dynamic networks, which different links yield signal qualities. We study rate-adaptive joint coding and modulation, often called coded modulation (CM), addressing non-dispersion-managed (non-DM) links, recent advances channel modeling of these links. introduce a four-dimensional CM scheme, shows better tradeoff between digital processing complexity transparent reach than existing methods....
Most of the calculations in standard sphere decoders are redundant, sense that they either calculate quantities never used or some more than once. A new method, which is applicable to lattices as well finite constellations, proposed avoid these redundant while still returning same result. Pseudocode given facilitate immediate implementation. Simulations show speed gain with method increases linearly lattice dimension. At dimension 60, algorithms about 75% all floating-point operations.
Coded modulation (CM) is the combination of forward error correction (FEC) and multilevel constellations. Coherent optical communication systems result in a four-dimensional (4D) signal space, which naturally leads to 4D-CM transceivers. A practically attractive design paradigm use bit-wise decoder, where detection process (suboptimally) separated into two steps: soft-decision demapping followed by binary decoding. In this paper, decoders are studied from an information-theoretic viewpoint....
In this paper, we study the joint resource allocation in flexible-grid networks based on a nonlinear physical layer impairment model. An optimization problem is formulated to assign resources and guarantee signal quality for every channel. Compared with fixed-grid wavelength-division multiplexing scenario, our method achieves significant bandwidth reduction transmission distance extension networks. The maximum spectrum usage shown be insensitive ordering of channels. We also analyze relation...
This paper investigates the impact of transceiver noise on performance digital back-propagation (DBP). A generalized expression to estimate signal-to-noise ratio (SNR) obtained using DBP in presence is described. new correctly accounts for nonlinear beating between and signal optical fiber transmission link. The noise-signal has been identified as main reason discrepancy predicted practical DBP; which not previously suggested. included GN model, allowing gains systems be analytically....
Resource allocation for transport optical networks has traditionally used a transmission reach constraint to estimate physical impairments. For flexible-grid networks, nonlinear impairments are not sufficiently well characterized by the since various modulations and bandwidths can coexist on same link. We propose resource algorithm single fiber link based signal distortion model, as first step toward whole-network design. An optimization problem is formulated provide close-to-optimal that...
We show that the channel distortion for maximum-entropy encoders, due to noise on a binary-symmetric channel, is minimized if vector quantizer can be expressed as linear transform of hypercube. The index assignment problem regarded linearizing quantizer. define classes assignments with related properties, within which best found by sorting, not searching. Two powerful algorithms assigning indices codevectors nonredundant coding systems are presented. One algorithm finds optimal solution in...