| 1. |
- Farsi, Mohammad, 1994, et al.
(författare)
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Pilot distributions for phase noise estimation in electro-optic frequency comb systems
- 2023
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Ingår i: European Conference on Optical Communication, ECOC.
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Konferensbidrag (refereegranskat)abstract
- We explore the optimal pilot positioning for phase tracking in electro-optic frequency comb setups. We show that, in contrast to previous results for regular multichannel systems, allocating the first and the last channels for pilots is optimal given a fixed pilot overhead.
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| 2. |
- Czegledi, Cristian Bogdan, 1988, et al.
(författare)
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Modified Digital Backpropagation Accounting for Polarization-Mode Dispersion
- 2017
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Ingår i: Optical Fiber Communication Conference. - 9781943580231
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Konferensbidrag (refereegranskat)abstract
- We propose a modified DBP algorithm accounting for PMD. The accumulated PMD at the receiver is factorized into several PMD sections, and inserted into the DBP routine to distributively compensate for PMD, outperforming the conventional approach by 1.1 dB in SNR.
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| 3. |
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| 4. |
- Olofsson, Frida, 1992, et al.
(författare)
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Investigation of Fiber Length Differences in Distributed MIMO Sigma-Delta-over-Fiber Systems
- 2023
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Ingår i: 49th European Conference on Optical Communications (ECOC 2023). - 9781839539268
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Konferensbidrag (refereegranskat)abstract
- The effect of having different fiber length to each access point in distributed MIMO is experimentally investigated through testbed experiments. It is found that the delay differences can severely degrade the performance of the system. A method for compensating the delay effect is proposed.
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| 5. |
- Tong, Zhi, 1977, et al.
(författare)
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Noise figure measurements in phase-insensitive and phase-sensitive fiber parametric amplifier cascade
- 2010
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Ingår i: Optical Fiber Communication Conference, OFC 2010; San Diego, CA; United States; 21 March 2010 through 25 March 2010. - 2162-2701. - 9781557528841 ; , s. OWT4-
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Konferensbidrag (refereegranskat)abstract
- By cascading two non-degenerate inline fiber-optic parametric amplifiers, we observe NF ~2dB (beating phase-insensitive quantum limit) at 16-dB gain for the second (phase-sensitive) stage after subtracting the excess noise from the first (phase-insensitive) stage.
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| 6. |
- Fougstedt, Christoffer, 1990, et al.
(författare)
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ASIC Implementation of Time-Domain Digital Back Propagation for Coherent Receivers
- 2018
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 30:13, s. 1179-1182
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Tidskriftsartikel (refereegranskat)abstract
- Digital back propagation (DBP) is often proposed and implemented offline for the mitigation of nonlinear impairments in long-haul fiber communications. However, complexity in terms of chip area and power consumption in a realistic application-specific integrated circuit implementation is yet to be determined. Here, we implement time-domain DBP (TD-DBP) in a 28-nm fully-depleted silicon-on-insulator process technology, considering digital implementation aspects such as limited-resolution arithmetic and finite-length filters. We choose as example a coherent optical transmission system, viz. a single-channel, single-polarization, and 20-GBd 16-QAM system, for which the DBP is known to perform well. For the considered system, we find that the TD-DBP can enable a reach increase from 3400 to 5300 km, at a power dissipation of <20 W (or, conversely, an energy dissipation of <230 pJ/bit), at a pre-FEC BER of 10-2.
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| 7. |
- Jorgensen, A. A., et al.
(författare)
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Petabit-per-second data transmission using a chip-scale microcomb ring resonator source
- 2022
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 16:11, s. 798-802
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Tidskriftsartikel (refereegranskat)abstract
- Optical fibre communication is the backbone of the internet. As essential core technologies are approaching their limits of size, speed and energy-efficiency, there is a need for new technologies that offer further scaling of data transmission capacity. Here we show that a single optical frequency-comb source based on a silicon nitride ring resonator supports data capacities in the petabit-per-second regime. We experimentally demonstrate transmission of 1.84 Pbit s–1 over a 37-core, 7.9-km-long fibre using 223 wavelength channels derived from a single microcomb ring resonator producing a stabilized dark-pulse Kerr frequency comb. We also present a theoretical analysis that indicates that a single, chip-scale light source should be able to support 100 Pbit s–1 in massively parallel space-and-wavelength multiplexed data transmission systems. Our findings could mark a shift in the design of future communication systems, targeting device-efficient transmitters and receivers.
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| 8. |
- Li, Shen, 1994, et al.
(författare)
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Antialiased transmitter-side digital backpropagation
- 2020
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 32:18, s. 1211-1214
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Tidskriftsartikel (refereegranskat)abstract
- Digital backpropagation (DBP) is an electronic scheme for compensating nonlinear distortions in fiber transmission systems. Due to the nonlinearity-induced spectral broadening, the data must be oversampled to avoid aliasing, which increases the complexity and power consumption of the scheme. In this work, we show that aliasing can alternatively be prevented by distributed antialiasing filters, at a lower complexity. We proposed a new modified split-step Fourier method (SSFM) with easy-To-implement low-pass filters (LPFs) in the linear steps to avoid aliasing due to spectral broadening. Both the forward fiber propagation and a transmitter-side DBP are simulated using the modified SSFM. High-order modulation formats such as 256-Ary quadrature-Amplitude-modulation (256-QAM) and 1024-QAM transmissions at 28 Gbaud and 64 Gbaud over 1000 km fiber are considered, and our results show that the complexity of the DBP can be reduced by up to 50%. The optimal bandwidth of the LPFs is studied for both forward propagation and the DBP.
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| 9. |
- Li, Shen, 1994, et al.
(författare)
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Power-Efficient Voronoi Constellations for Fiber-Optic Communication Systems
- 2023
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 41:5, s. 1298-1308
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Tidskriftsartikel (refereegranskat)abstract
- Voronoi constellations (VCs) are considered as an effective geometric shaping method due to their high power efficiencies and low complexity. In this paper, the performance of 16- and 32-dimensional VCs with a variety of spectral efficiencies transmitted in the nonlinear fiber channel are investigated. Both single-channel and wavelength-division multiplexing systems are considered for the transmission of the VCs, as well as different signal processing schemes, including chromatic dispersion compensation and digital backpropagation. Multiple performance metrics including the uncoded bit error rate, mutual information (MI), and generalized mutual information (GMI) of VCs are evaluated. Compared with quadrature amplitude modulation (QAM) formats, the VCs provide 1.0--2.4 dB launch power gains, up to 0.50 bits/symbol/dimension-pair MI gains, up to around 30% potential reach increase at the same MI, and up to 0.30 bits/symbol/dimension-pair GMI gains in a limited launch power range. The observed performance gains over QAM are found higher than in the back-to-back case. Moreover, a general GMI estimation method for very large constellations using importance sampling is proposed for the first time.
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| 10. |
- Lundberg, Lars, 1989, et al.
(författare)
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Power Consumption Savings Through Joint Carrier Recovery for Spectral and Spatial Superchannels
- 2018
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Ingår i: European Conference on Optical Communication, ECOC. ; 2018-September
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Konferensbidrag (refereegranskat)abstract
- The power consumption of a circuit implementation of a master-slave carrier recovery scheme is studied. Slave power consumption is 27% of master power for 16QAM and 13% for 64QAM, enabling power savings approaching 0.7W per channel through joint processing.
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