| 1. |
- Mazur, Mikael, 1990, et al.
(författare)
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11.5 bits/s/Hz PM-256QAM Comb-Based Superchannel Transmission by Combining Optical and Digital Pilots
- 2018
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Ingår i: 2018 Optical Fiber Communications Conference and Exposition, OFC 2018 - Proceedings. - 9781943580385
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Konferensbidrag (refereegranskat)abstract
- We demonstrate 44 Tb/s transmission using three 50x24 Gbaud PM-256QAM comb-based superchannels. Each superchannel combines a single optical pilot tone with individual digital pilot symbols to minimize the total overhead, enabling record spectral-efficiency over the full C-band.
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| 2. |
- Mazur, Mikael, 1990, et al.
(författare)
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12 bits/s/Hz Spectral Efficiency Over the C-band Based on Comb-Based Superchannels
- 2019
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 37:2, s. 411-417
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Tidskriftsartikel (refereegranskat)abstract
- We present transmission of three 50×24 Gbaud PM-256QAM superchannels with an overall spectral efficiency of 12 bits/s/Hz over the entire C-band. Each comb-based superchannel combines a single shared optical pilot tone with a low-overhead pilot-based DSP. The pilot tone is used to lock the transmitter and the receiver comb seed lasers, suppressing carrier offsets. Combined with optimized insertion ratio of the digital pilot symbols, the total overhead is minimized, avoiding any excess loss in spectral efficiency. Our results demonstrate the feasibility to exploit the unique properties of frequency combs in the design of high spectral efficiency multi-Tb/s superchannels.
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| 3. |
- Mazur, Mikael, 1990, et al.
(författare)
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Overhead-optimization of pilot-based digital signal processing for flexible high spectral efficiency transmission
- 2019
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 27:17, s. 24654-24669
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Tidskriftsartikel (refereegranskat)abstract
- We present a low-complexity fully pilot-based digital signal processing (DSP) chain designed for high spectral efficiency optical transmission systems. We study the performance of the individual pilot algorithms in simulations before demonstrating transmission of a 51×24 Gbaud PM-64QAM superchannel over distances reaching 1000 km. We present an overhead optimization technique using the system achievable information rate to find the optimal balance between increased performance and throughput reduction from adding additional DSP pilots. Using the optimal overhead of 2.4%, we report 9.3 (8.3) bits/s/Hz spectral efficiency, or equivalently 11.9 (10.6) Tb/s superchannel throughput, after 480 (960) km of transmission over 80 km spans with EDFA-only amplification. Moreover, we show that the optimum overhead depends only weakly on transmission distance, concluding that back-to-back optimization is sufficient for all studied distances. Our results show that pilot-based DSP combined with overhead optimization can increase the robustness and performance of systems using advanced modulation formats while still maintaining state-of-the-art spectral efficiency and multi-Tb/s throughput.
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| 4. |
- Yoshida, Tsuyoshi, 1982, et al.
(författare)
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Compressed Shaping: Concept and FPGA Demonstration
- 2021
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 39:17, s. 5412-5422
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Tidskriftsartikel (refereegranskat)abstract
- Probabilistic shaping (PS) has been widely studied and applied to optical fiber communications. The encoder of PS expends the number of bit slots and controls the probability distribution of channel input symbols. Not only studies focused on PS but also most works on optical fiber communications have assumed source uniformity (i.e. equal probability of marks and spaces) so far. On the other hand, the source information is in general nonuniform, unless bit-scrambling or other source coding techniques to balance the bit probability is performed. Interestingly, one can exploit the source nonuniformity to reduce the entropy of the channel input symbols with the PS encoder, which leads to smaller required signal-to-noise ratio at a given input logic rate. This benefit is equivalent to a combination of data compression and PS, and thus we call this technique compressed shaping. In this work, we explain its theoretical background in detail, and verify the concept by both numerical simulation and a field programmable gate array (FPGA) implementation of such a system. In particular, we find that compressed shaping can reduce power consumption in forward error correction decoding by up to 90% in nonuniform source cases. The additional hardware resources required for compressed shaping are not significant compared with forward error correction coding, and an error insertion test is successfully demonstrated with the FPGA.
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| 5. |
- Yoshida, Tsuyoshi, 1982, et al.
(författare)
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Efficient Offline Evaluation of FEC Codes Based on Captured Data with Probabilistic Shaping
- 2018
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Ingår i: 2018 Optical Fiber Communications Conference and Exposition, OFC 2018 - Proceedings. - 9781943580385
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Konferensbidrag (refereegranskat)abstract
- We propose a tool for reusing experimental or simulation data of probabilistically shaped signals with different FEC codes. A single recorded histogram of log-likelihood ratios is sufficient to examine arbitrary coding at low BERs.
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| 6. |
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| 7. |
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| 8. |
- Yoshida, Tsuyoshi, 1982, et al.
(författare)
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Joint Source-Channel Coding via Compressed Distribution Matching in Fiber-Optic Communications
- 2019
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Ingår i: 2019 Optical Fiber Communications Conference and Exhibition, OFC 2019 - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- The variability of source entropy due to data idling is inconsistent with most studies' assumptions in probabilistic shaping. We propose a distribution matcher sensitive to the source entropy, and discuss its impacts on fiber-optic communications.
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| 9. |
- Yoshida, Tsuyoshi, 1982, et al.
(författare)
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Low-Complexity Symbol Demapping for Multidimensional Multilevel Coded Modulation
- 2022
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Ingår i: European Conference on Optical Communication, ECOC. ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- Symbol demapping for multidimensional multilevel coding (MLC) is proposed, together with a novel nonsystematic encoding method, applicable to any dimensionality. The complexity of soft-decision forward error correction and symbol demapping, both normally problematic in multidimensional MLC, is reduced, which enables high-throughput implementation.
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| 10. |
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