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Träfflista för sökning "WFRF:(Johannisson Pontus) srt2:(2015-2019)"

Sökning: WFRF:(Johannisson Pontus) > (2015-2019)

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1.
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2.
  • Czegledi, Cristian Bogdan, 1988, et al. (författare)
  • Modulation Format Independent Joint Polarization and Phase Tracking for Coherent Receivers
  • 2016
  • Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 13:14, s. 3354-3364
  • Tidskriftsartikel (refereegranskat)abstract
    • © 1983-2012 IEEE. The state of polarization and the carrier phase drift dynamically during transmission in a random fashion in coherent optical fiber communications. The typical digital signal processing solution to mitigate these impairments consists of two separate blocks that track each phenomenon independently. Such algorithms have been developed without taking into account mathematical models describing the impairments. We study a blind, model-based tracking algorithm to compensate for these impairments. The algorithm dynamically recovers the carrier phase and state of polarization jointly for an arbitrary modulation format. Simulation results show the effectiveness of the proposed algorithm, having a fast convergence rate and an excellent tolerance to phase noise and dynamic drift of the polarization at low complexity, which make the algorithm a strong candidate for future optical systems.
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3.
  • Czegledi, Cristian Bogdan, 1988, et al. (författare)
  • Polarization Drift Channel Model for Coherent Fibre-Optic Systems
  • 2016
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 6, s. 21217-
  • Tidskriftsartikel (refereegranskat)abstract
    • A theoretical framework is introduced to model the dynamical changes of the state of polarization during transmission in coherent fibre-optic systems. The model generalizes the one-dimensional phase noise random walk to higher dimensions, accounting for random polarization drifts, emulating a random walk on the Poincare sphere, which has been successfully verified using experimental data. The model is described in the Jones, Stokes and real four-dimensional formalisms, and the mapping between them is derived. Such a model will be increasingly important in simulating and optimizing future systems, where polarization-multiplexed transmission and sophisticated digital signal processing will be natural parts. The proposed polarization drift model is the first of its kind as prior work either models polarization drift as a deterministic process or focuses on polarization-mode dispersion in systems where the state of polarization does not affect the receiver performance. We expect the model to be useful in a wide-range of photonics applications where stochastic polarization fluctuation is an issue.
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4.
  • Czegledi, Cristian Bogdan, 1988, et al. (författare)
  • Temporal stochastic channel model for absolute polarization state and polarization-mode dispersion
  • 2017
  • Ingår i: 2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings. - 2162-2701. - 9781943580231
  • Konferensbidrag (refereegranskat)abstract
    • We propose and validate a discrete-time channel model for the temporal drift of the absolute polarization state and polarization-mode dispersion for coherent fiber optic systems. The model can be used in simulations to test and develop DSP for coherent receivers.
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5.
  • Eliasson, Henrik, 1985, et al. (författare)
  • Mitigation of nonlinearities using conjugate data repetition
  • 2015
  • Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 23:3, s. 2392-2402
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigate a time-domain implementation of generalized phase-conjugated twin waves which we call conjugate data repetition. A theory based on time-domain perturbation analysis explaining the mitigation of nonlinear effects is provided, and the concept is evaluated using numerical simulations. Compared to PM-QPSK at the same channel bit rate, the single-channel transmission reach in a conventional system with standard single-mode fiber of conjugate data repetition-QPSK is increased by approximately a factor of 2.
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6.
  • Eriksson, Tobias, 1986, et al. (författare)
  • Achievable Rates Comparison for Phase-Conjugated Twin-Waves and PM-QPSK
  • 2016
  • Ingår i: 21st OptoElectronics and Communications Conference, OECC 2016 - Held Jointly with 2016 International Conference on Photonics in Switching, PS 2016, Niigata, Japan, 3-7 July 2016. - 9784885523052 ; , s. TuB3-3
  • Konferensbidrag (refereegranskat)abstract
    • Phase-conjugated twin-waves (PCTW)-QPSK is experimentally compared to PM-QPSK in terms of achievable information rate for bit-wise decoders. For typical long-haul transmission distances, PM-QPSK with soft-decision FEC achieves significantly higher spectral efficiency than PCTW-QPSK.
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7.
  • Fehenberger, Tobias, et al. (författare)
  • On the impact of carrier phase estimation on phase correlations in coherent fiber transmission
  • 2015
  • Ingår i: 2015 Tyrrhenian International Workshop on Digital Communications, TIWDC 2015. - 9781467392600 ; , s. 35-38
  • Konferensbidrag (refereegranskat)abstract
    • Carrier phase estimation (CPE) is an integral part of the digital signal processing (DSP) of coherent optical communication systems as it compensates laser phase noise (LPN) introduced by free-running transmitter and local oscillating (LO) lasers. Nonlinear interactions during propagation are another source of correlated phase noise. In this paper, we show through simulations and in experiments that blind decision-directed (DD) CPE with regular block lengths removes a large portion of the memory. This makes it virtually impossible in practice to quantify correlations that come from propagation effects, or to obtain rate gains by exploiting the nonlinear phase noise (NLPN). Larger CPE block lengths leave the memory partly intact. This, however, comes at the expense of reduced information rates. We are able to fully recover this rate loss in simulations by using idealized processing of phase distortions. In experiments with full DSP, an almost full rate recovery is reported.
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8.
  • Fougstedt, Christoffer, 1990, et al. (författare)
  • Dynamic Equalizer Power Dissipation Optimization
  • 2016
  • Ingår i: 2016 Optical Fiber Communications Conference and Exhibition. - 9781943580071
  • Konferensbidrag (refereegranskat)abstract
    • We investigate power dissipation/performance trade-off in a 28nm ASIC implementation of a parallel dynamic equalizer. Over 50% dissipation improvement is possible by sample pruning during filter updates, with only minor tracking-performance reduction.
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9.
  • Fougstedt, Christoffer, 1990, et al. (författare)
  • Filter Implementation for Power-Efficient Chromatic Dispersion Compensation
  • 2018
  • Ingår i: IEEE Photonics Journal. - 1943-0655. ; 10:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Chromatic dispersion (CD) compensation in coherent fiber-optic systems represents a very significant DSP block in terms of power dissipation. Since spectrally efficient coherent systems are expected to find a wider deployment in systems shorter than long haul, it becomes relevant to investigate filter implementation aspects of CD compensation in the context of systems with low-to-moderate amounts of accumulated dispersion. The investigation we perform in this paper has an emphasis on implementation aspects such as power dissipation and area usage, it deals with both time-domain and frequency-domain CD compensations, and it considers both A/D-conversion quantization and fixed-point filter design aspects. To enable an accurate analysis on power dissipation and chip area, the evaluated filters are implemented in a 28-nm fully depleted silicon-on-insulator (FD-SOI) process technology. We show that an optimization of the filter response that takes pulse shaping into account can significantly reduce power dissipation and area usage of time-domain implementations, making them a viable alternative to frequency-domain implementations.
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10.
  • Fougstedt, Christoffer, 1990, et al. (författare)
  • Power-Efficient Time-Domain Dispersion Compensation Using Optimized FIR Filter Implementation
  • 2015
  • Ingår i: Signal Processing in Photonics Communications, SPPCom 2015; Boston, MA; United States; 27 June 2015-1 July 2015. - 9781557520005 ; , s. SpT3D.3-
  • Konferensbidrag (refereegranskat)abstract
    • We investigate fixed-point aspects and time-domain ASIC implementations of CD compensation. An optimized implementation gives significant power dissipation reduction for short links, with further reduction if pulse shaping is considered.
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11.
  • Irukulapati, Naga Vishnukanth, 1987, et al. (författare)
  • Improved Lower Bounds on Mutual Information Accounting for Nonlinear Signal--Noise Interaction
  • 2018
  • Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 36:22, s. 5152-5159
  • Tidskriftsartikel (refereegranskat)abstract
    • In fiber-optic communications, evaluation of mutual information (MI) is still an open issue due to the unavailability of an exact and mathematically tractable channel model. Traditionally, lower bounds on MI are computed by approximating the (original) channel with an auxiliary forward channel. In this paper, lower bounds are computed using an auxiliary backward channel, which has not been previously considered in the context of fiber-optic communications. Distributions obtained through two variations of the stochastic digital backpropagation (SDBP) algorithm are used as auxiliary backward channels and these bounds are compared with bounds obtained through the conventional digital backpropagation (DBP). Through simulations, higher information rates were achieved with SDBP, which can be explained by the ability of SDBP to account for nonlinear signal--noise interactions
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12.
  • Irukulapati, Naga Vishnukanth, 1987, et al. (författare)
  • Stochastic Digital Backpropagation with Residual Memory Compensation
  • 2016
  • Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 34:2, s. 566-572
  • Tidskriftsartikel (refereegranskat)abstract
    • Stochastic digital backpropagation (SDBP) is an extension of digital backpropagation (DBP) and is based on the maximum a posteriori principle. SDBP takes into account noise from the optical amplifiers in addition to handling deterministic linear and nonlinear impairments. The decisions in SDBP are taken on a symbol-by-symbol (SBS) basis, ignoring any residual memory, which may be present due to non-optimal processing in SDBP. In this paper, we extend SDBP to account for memory between symbols. In particular, two different methods are proposed: a Viterbi algorithm (VA) and a decision directed approach. Symbol error rate (SER) for memory-based SDBP is significantly lower than the previously proposed SBS-SDBP. For inline dispersion-managed links, the VA-SDBP has up to 10 and 14 times lower SER than DBP for QPSK and 16-QAM, respectively.
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13.
  • Johannisson, Pontus, et al. (författare)
  • Impact-driven up-conversion in piezoelectric MEMS energy harvesters with pulsed excitation
  • 2018
  • Ingår i: Journal of Physics. - : IOP Publishing.
  • Konferensbidrag (refereegranskat)abstract
    • The potential of impact-driven frequency up-conversion in a MEMS EH is evaluated using numerical simulations. The investigated design is compared to a conventional cantilever EH in terms of output power and loss rate. The upshifting can lead to significantly increased output power at a similar loss rate but as the time scale for the loss is long, the benefit is limited. This also requires an effective upshifting process. The design of the impact introduces a length scale that must be selected with excitation, gravity, and pre-stress taken into account. This makes this type of EH application-dependent as a non-optimal choice may result in low output power.
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14.
  • Johannisson, Pontus, et al. (författare)
  • Multi-axis piezoelectric energy harvesting using MEMS components with slanted beams
  • 2016
  • Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 773:1
  • Tidskriftsartikel (refereegranskat)abstract
    • During the manufacturing of MEMS components, slanted beams can be produced in the etching process. We show that this can be used to produce skew motion that causes deflection of a proof mass out of the device plane also when the excitation is confined to the device plane. This allows construction of an energy harvester that uses a planar manufacturing process and produces power also with in-plane excitation. To obtain this with traditional methods it would be necessary to manufacture separate components and then mount them with their sensitive axes orthogonal to each other.
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15.
  • Köhler, Elof, 1980, et al. (författare)
  • MEMS meander harvester with tungsten proof-mass
  • 2019
  • Ingår i: Journal of Physics. - : Institute of Physics Publishing.
  • Konferensbidrag (refereegranskat)abstract
    • Using current battery technology the life-time of a leadless pacemaker is approximately 6-10 years, with a large portion of the pacemaker occupied by the battery. This paper investigates the possibility to use a MEMS piezoelectric harvester as a complementary energy source in leadless pacemakers. The challenge is to combine the low resonance frequency required to harvest energy from a heartbeat with the small volume of 20×4×3 mm3 available, with the corresponding harvester displacement restricted to 2 mm. Due to the displacement restriction the selected structure was a double clamped bridge in order to reduce the mass displacement, with various meander-type designs simulated to reduce resonance frequency. To further reduce resonance frequency large proof-masses of tungsten were attached by gluing. Two types of tungsten proof-masses were added to four different harvesters, 16.4 mg and 16.6 mg on sample 1 and 2 and 502 mg and 492 mg proof-mass on sample 3 and 4. The structures have 2 μm patterned PZT (deposited by sol-gel technique) and Pt metal electrodes for d31 mode harvesting. The power output measured from one of the two PZT/electrodes was 0.13 nW with 50 μm deflection at 100 k Ω optimal load resistance and 9.1 mVpp at 232 Hz.
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16.
  • Larsson, S., et al. (författare)
  • Simple method for quality factor estimation in resonating MEMS structures
  • 2018
  • Ingår i: Proceedings of the 17th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications, 2017. - : IOP Publishing.
  • Konferensbidrag (refereegranskat)abstract
    • The quality factor of a packaged MEMS resonating structure depends on both the packaging pressure and the structure's proximity to the walls. This type of mechanical constraints, which causes energy dissipation from the structure to the surrounding air, are applicable for oscillating energy harvesters and should be considered in the design process. However, the modelling of energy losses or the measurements of their direct influence inside a packaged chip is not trivial. In this paper, a simple experimental method to quantify the energy loss in an oscillating MEMS structures due to the surrounding air is described together with preliminary results. The main advantage of the method is the ability to characterize the damping contributions under different vacuum and packaging conditions without requiring any packaging of the harvester chip or fabrication of multiple devices with different cavity depths. © Published under licence by IOP Publishing Ltd.
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17.
  • Lundberg, Lars, 1989, et al. (författare)
  • In-Band OSNR Monitoring of PM-QPSK Using the Stokes Parameters
  • 2015
  • Ingår i: 2015 Optical Fiber Communications Conference and Exhibition, OFC 2015, Los Angeles, United States, 22-26 March 2015. - Washington, D.C. : OSA. - 9781557529374 ; , s. 7122095-
  • Konferensbidrag (refereegranskat)abstract
    • We discuss OSNR monitoring using low bandwidth Stokes parameter analysis. OSNR levels reaching 23dB are experimentally estimated within ±1dB. Simulations show resilience to chromatic dispersion, corresponding to 1000km of SMF for the experimental setup.
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18.
  • Lundberg, Lars, 1989, et al. (författare)
  • Power Consumption of Hybrid EDFA/Raman Amplified Systems
  • 2015
  • Ingår i: 41st European Conference on Optical Communication, ECOC 2015, Valencia, Spain, 27 September 2015 - 1 October 2015. - 9788460817413 ; 2015-November
  • Konferensbidrag (refereegranskat)abstract
    • We analyze the power consumption in hybrid EDFA/Raman amplified links along with the trade-off of span distance and the use of FEC. A simple model provides some guidelines for the choices to be made.
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19.
  • Lundström, Carl Peter, 1982, et al. (författare)
  • Mask testing of 28 gbaud 16-QAM transmitters using time-resolved error vector magnitude
  • 2015
  • Ingår i: Signal Processing in Photonic Communications, SPPCom 2015; Omni Parker HouseBoston; United States; 27 June 2015 through 1 July 2015. - 9781557520005 ; , s. SpS4D.3-
  • Konferensbidrag (refereegranskat)abstract
    • We propose time-resolved EVM for characterization of 16-QAM transmitters. By designing a mask test, different impairments can be separated and quantified. The impact from quadrature error and timing skew are investigated experimentally.
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20.
  • Ohlsson, Fredrik, et al. (författare)
  • Shape effects in doubly clamped bridge structures at large deflections
  • 2018
  • Ingår i: Journal of Physics. - : IOP Publishing.
  • Konferensbidrag (refereegranskat)abstract
    • The shape of a doubly clamped bridge structure depends on its deflection. At large deflections, where the system exhibits nonlinear behaviour, the shape effect becomes significant. We present a general method, based on variational analysis, for computing corrections to the nominal linear regime shape function. The method is used to compute the first non-trivial correction and quantify the corresponding improvement in the large deflection regime. The model obtained is also validated using FEM simulations.
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21.
  • Sheikh, Alireza, 1989, et al. (författare)
  • Dispersion Compensation Filter Design Optimized for Robustness and Power Efficiency
  • 2015
  • Ingår i: Signal Processing in Photonics Communications, SPPCom 2015; Boston, MA; United States; 27 June 2015 through 1 July 2015. - 9781557520005 ; , s. SpT3D.2-
  • Konferensbidrag (refereegranskat)abstract
    • We present an optimized CD compensation filter with improved performance and increased resilience to quantization errors. The filter is given in closed form based on a constrained least-squares problem.
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22.
  • Sheikh, Alireza, 1989, et al. (författare)
  • Dispersion Compensation FIR Filter with Improved Robustness to Coefficient Quantization Errors
  • 2016
  • Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 34:22, s. 5110-5117
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, we propose a new finite impulseresponse (FIR) filter for chromatic dispersion compensation which is given in closed form. We identify a relation between the out-of-band gain and the in-band error when the filter is implemented with finite-precision arithmetic. In particular, a large out-of-band gain makes the filter more sensitive tocoefficient quantization errors due to finite precision digital signal processing. To improve robustness to coefficient quantization errors, our proposed filter is designed based on confining the out-of-band gain. By means of simulations, we show that our filter outperforms other existing FIR filters. The performance gain improves with increasing modulation order and decreasing number of bits used to represent the filter taps.
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23.
  • Wymeersch, Henk, 1976, et al. (författare)
  • Backward particle message passing
  • 2015
  • Ingår i: IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC. - 9781479919307 ; 2015-August, s. 450-454
  • Konferensbidrag (refereegranskat)abstract
    • Particle methods are an established way to represent messages and perform message passing in factor graphs. Despite their common use, there are several cases for which messages are hard to compute, even in linear models. Building on results from Gaussian message passing, we demonstrate how backward particle-based messages can be computed and describe a practical application in the context of fiber-optical communications.
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24.
  • Wymeersch, Henk, 1976, et al. (författare)
  • On the Use of Factor Graphs in Optical Communications
  • 2015
  • Ingår i: 2015 Optical Fiber Communications Conference and Exhibition, OFC 2015; Los Angeles; United States; 22 March - 26 March 2015. - 9781557529374 ; 2015-June:7122132
  • Konferensbidrag (refereegranskat)abstract
    • Factor graphs and message passing allow the near-automated development of algorithms in many engineering disciplines, including digital communications. This paper gives an overview of their possible use in optical communications.
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25.
  • Yan, Li, 1988, et al. (författare)
  • Link-Level Resource Allocation for Flexible-Grid Nonlinear Fiber-Optic Communication Systems
  • 2015
  • Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 27:12, s. 1250-1253
  • Tidskriftsartikel (refereegranskat)abstract
    • 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 transmission reach since various modulations and bandwidths can coexist on the same link. We propose a resource allocation algorithm for a single flexible-grid fiber link based on a nonlinear signal distortion model, as a first step towards whole-network design. An optimization problem is formulated to provide a close-to-optimal resource allocation that guarantees the quality of transmission for every channel. Compared with a simpler algorithm based on transmission reach, our proposed algorithm shows the potential of bandwidth savings. It is demonstrated to be insensitive to channel ordering.
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26.
  • Yao, SC, et al. (författare)
  • Fast and robust chromatic dispersion estimation based on temporal auto-correlation after digital spectrum superposition
  • 2015
  • Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 23:12, s. 15418-15430
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigate and experimentally demonstrate a fast and robust chromatic dispersion (CD) estimation method based on temporal auto-correlation after digital spectrum superposition. The estimation process is fast, because neither tentative CD scanning based on CD compensation nor specific cost function calculations are used. Meanwhile, the proposed CD estimation method is robust against polarization mode dispersion (PMD), amplified spontaneous emission (ASE) noise and fiber nonlinearity. Furthermore, the proposed CD estimation method can be used for various modulation formats and digital pulse shaping technique. Only 4096 samples are necessary for CD estimation of single carrier either 112 Gbps DP-QPSK or 224 Gbps DP-16QAM signal with various pulse shapes. 8192 samples are sufficient for the root-raised-cosine pulse with roll-off factor of 0.1. As low as 50 ps/nm standard deviation together with a worst estimation error of about 160 ps/nm is experimentally obtained for 7 x 112 Gbps DP-QPSK WDM signal after the transmission through 480 km to 9120 km single mode fiber (SMF) loop using different launch powers.
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