| 211. |
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| 212. |
- Karout, Johnny, 1985, et al.
(författare)
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Optimizing Constellations for Single-Subcarrier Intensity-Modulated Optical Systems
- 2012
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Ingår i: IEEE Transactions on Information Theory. - 0018-9448 .- 1557-9654. ; 58:7, s. 4645-4659
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Tidskriftsartikel (refereegranskat)abstract
- We optimize modulation formats for the additive white Gaussian noise channel with nonnegative input, also known as the intensity-modulated direct-detection channel, with and without confining them to a lattice structure. Our optimization criteria are the average electrical, average optical, and peak power. The nonnegative constraint on the input to the channel is translated into a conical constraint in signal space, and modulation formats are designed by sphere packing inside this cone. Some dense packings are found, which yield more power-efficient modulation formats than previously known. For example, at a spectral efficiency of 1.5 bit/s/Hz, the modulation format optimized for average electrical power has a 2.55 dB average electrical power gain over the best known format to achieve a symbol error rate of 10-6 . The corresponding gains for formats optimized for average and peak optical power are 1.35 and 1.72 dB, respectively. Using modulation formats optimized for peak power in average-power limited systems results in a smaller power penalty than when using formats optimized for average power in peak-power limited systems. We also evaluate the modulation formats in terms of their mutual information to predict their performance in the presence of capacity-achieving error-correcting codes, and finally show numerically and analytically that the optimal modulation formats for reliable transmission in the wideband regime have only one nonzero point.
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| 213. |
- Karout, Johnny, 1985, et al.
(författare)
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Power efficient subcarrier modulation for intensity modulated channels
- 2010
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 18:17, s. 17913-17921
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Tidskriftsartikel (refereegranskat)abstract
- We compare formats for optical intensity modulation limited by thermal noise with the assumption of having ideal devices. At the same bitrate and bandwidth, a hitherto unknown format turns out to be more power efficient than known formats. This new modulation, which is a hybrid between on-off keying and phase-shift keying, belongs to the subcarrier modulation family. At asymptotically high signal-to-noise ratios, this hybrid scheme has a 1.2 dB average electrical power gain and 0.6 dB average optical power gain compared to OOK, while it has a 3.0 dB average electrical power gain and 2.1 dB average optical power gain compared to subcarrier QPSK.
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| 214. |
- Keykhosravi, Kamran, 1990, et al.
(författare)
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When to Use Optical Amplification in Noncoherent Transmission: An Information-Theoretic Approach
- 2020
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Ingår i: IEEE Transactions on Communications. - 0090-6778 .- 1558-0857. ; 68:4, s. 2438-2445
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Tidskriftsartikel (refereegranskat)abstract
- The standard solution for short-haul fiber-optic communications is to deploy noncoherent systems, i.e., to modulate and detect only the light intensity. In such systems, the signal is corrupted with optical noise from amplifiers and with thermal (electrical) noise. The capacity of noncoherent optical links has been studied extensively in the presence of either optical noise or thermal noise. In this paper, for the first time, we characterize the capacity under an average power constraint with both noise sources by establishing upper and lower bounds. In the two extreme cases of zero optical noise or zero thermal noise, we assess our bounds against some well-known results in the literature; improvements in both cases are observed. Next, for amplified fiber-optic systems, we study the trade-off between boosting signal energy (mitigating the effects of thermal noise) and adding optical noise. For a wide spectrum of system parameters and received power levels, we determine the optimal amplification gain. While mostly either no amplification or high-gain amplification is optimal, the best performance is for some parameter intervals achieved at finite gains.
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| 215. |
- Khan, Fahd Ahmed, 1984, et al.
(författare)
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Electronic dispersion compensation by Hadamard transformation
- 2010
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Ingår i: Optical Fiber Communication Conference (OFC) - Proceedings. - Washington, D.C. : OSA. - 9781557528841 ; , s. paper OWV4-
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Konferensbidrag (refereegranskat)abstract
- We demonstrate that the Hadamard transform can be applied to look up table (LUT)-based predistorters to simultaneously compress and optimize the LUT for dispersion-limited links.
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| 216. |
- Kolltveit, Erling, et al.
(författare)
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Single-wavelength 40 Gbit/s soliton field transmission experiment over 400 km of installed fibre
- 1999
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 35:1, s. 75-76
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Tidskriftsartikel (refereegranskat)abstract
- 40Gbit/s soliton transmission over 400km (57km amplifier spacing) of installed lines without in-line control has been achieved. The maximum transmission penalties for parallel polarised and polarisation division multiplexed soliton transmission were ∼4 and 1dB, respectively. The transmission distance is the longest ever reported for a field trial with a single wavelength bit rate > 20Gbit/s for any optical transmission format. The polarisation mode dispersion was numerically found to completely dominate the system performance.
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| 217. |
- Kong, D., et al.
(författare)
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Single Dark-Pulse Kerr Comb Supporting 1.84 Pbit/s Transmission over 37-Core Fiber
- 2020
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Ingår i: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS. - 1092-8081. ; 2020-May
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Konferensbidrag (refereegranskat)abstract
- We show that a single dark-pulse Kerr comb can generate high enough OSNR to carry 1.84 Pbit/s data, achieved by 223 WDM spectral lines modulated with 32-Gbaud, SNR-adapted probabilistically shaped DP-QAM, over a 37-core fiber.
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| 218. |
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| 219. |
- Kylemark, Per, 1976, et al.
(författare)
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DM solitons in long-haul DWDM systems at 40 Gb/s with nonlinear interactions and PMD
- 2003
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Ingår i: IEEE Photonics Technology Letters. ; 15:10, s. 1372-4
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Tidskriftsartikel (refereegranskat)abstract
- The authors investigate for the first time how polarization mode dispersion and nonlinear interactions affect dense wavelength division multiplexing dispersion management-soliton long-haul transmission using Monte Carlo simulations. They also discuss how the system is affected by an increasing number of wavelength channels
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| 220. |
- Kylemark, Per, 1976, et al.
(författare)
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Gain and wavelength dependence of the noise-figure in fiber optical parametric amplification
- 2006
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Ingår i: IEEE Photonics Technology Letters. ; 18:11, s. 1255-7
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Tidskriftsartikel (refereegranskat)abstract
- We measure, for the first time, the wavelength resolved electrical noise figure (NF) of a fiber-optical parametric amplifier and find excellent agreement with theoretical predictions. We furthermore measure the NF in the exponential gain regime at high gain and quantify the gain dependence of the NF as well as its spectral dependence
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