| 1. |
- Agrell, Erik, 1965, et al.
(författare)
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Modulation and detection for multicore superchannels with correlated phase noise [Invited]
- 2018
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Ingår i: 2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings. ; Part F94-CLEO_SI 2018
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Konferensbidrag (refereegranskat)abstract
- SDM fibers offer new opportunities and challenges for joint transmitter and receiver processing. We review multidimensional modulation and detection theory, describe algorithms for phase tracking and detection over spatial superchannels, and present some experimental results.
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| 2. |
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| 3. |
- Eliasson, Henrik, 1985, et al.
(författare)
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Phase-sensitive amplifier link with distributed Raman amplification
- 2018
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 26:16, s. 19854-19863
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate long-haul transmission using a hybrid amplifier approach combining distributed Raman amplification and lumped phase-sensitive amplification. Aside from the well-known resulting SNR improvement, distributed Raman amplification is included in an effort to improve the nonlinearity mitigation capability of the phase-sensitive amplifiers. When changing from phase-insensitive operation to phase-sensitive operation in a link employing distributed Raman amplification, the transmission reach at BER = 10−3is increased from 15 to 44 spans of length 81 km while simultaneously increasing the optimal launch power by 2 dB.
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| 4. |
- 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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| 5. |
- Lengyel, Tamas, 1986, et al.
(författare)
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Pre-emphasis enabled 50 Gbit/s transmission over 1000 m SMF using a 1060 nm single-mode VCSEL
- 2018
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 54:20, s. 1186-1187
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Tidskriftsartikel (refereegranskat)abstract
- A single-mode 1060 nm vertical-cavity surface-emitting laser (VCSEL) and single-mode fibre (SMF) based link with two-tap active pre-emphasis enabling error-free transmission of 50 Gbit/s NRZ-OOK over 1000 m is presented.
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| 6. |
- Lundberg, Lars, 1989, et al.
(författare)
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Frequency Comb-Based WDM Transmission Systems Enabling Joint Signal Processing
- 2018
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Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- We review the use of optical frequency combs in wavelength-division multiplexed (WDM) fiber optic communication systems. In particular, we focus on the unique possibilities that are opened up by the stability of the comb-line spacing and the phase coherence between the lines. We give an overview of different techniques for the generation of optical frequency combs and review their use in WDM systems. We discuss the benefits of the stable line spacing of frequency combs for creating densely-packed optical superchannels with high spectral efficiency. Additionally, we discuss practical considerations when implementing frequency-comb-based transmitters. Furthermore, we describe several techniques for comb-based superchannel receivers that enables the phase coherence between the lines to be used to simplify or increase the performance of the digital carrier recovery. The first set of receiver techniques is based on comb-regeneration from optical pilot tones, enabling low-overhead self-homodyne detection. The second set of techniques takes advantage of the phase coherence by sharing phase information between the channels through joint digital signal processing (DSP) schemes. This enables a lower DSP complexity or a higher phase-noise tolerance.
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| 7. |
- Lundberg, Lars, 1989, et al.
(författare)
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Phase Correlation Between Lines of Electro-Optical Frequency Combs
- 2018
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Ingår i: Optics InfoBase Conference Papers. - 2162-2701.
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Konferensbidrag (refereegranskat)abstract
- Simultaneous measurement of the phase noise from 49 electro-optical frequency comb lines show a correlation of over 99.99% between lines. Additionally, the phase noise difference between line pairs is correlated, verifying theoretical predictions.
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| 8. |
- 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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| 9. |
- Mazur, Mikael, 1990, et al.
(författare)
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10 Tb/s PM-64QAM Self-Homodyne Comb-Based Superchannel Transmission with 4% Shared Pilot Tone Overhead
- 2018
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 36:16, s. 3176-3184
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate transmission of a comb-based 10 Tb/s 50 × 20 Gbaud PM-64QAM superchannel using frequency comb regeneration to reduce carrier offsets and allow for self-homodyne detection. The regeneration is enabled by transmitting two optical pilot tones which are filtered and recovered in the receiver using optical injection locking and an electrical phase-locked loop. We show that by utilizing frequency combs together with optical pilot tones, self-homodyne detection similar to systems using one pilot tone per wavelength channel, can be achieved. Sharing the overhead for pilot tones reduces the complexity and limits the overhead to 4%. This enabled a total superchannel spectral efficiency of 7.7 b/s/Hz. To evaluate the performance, we perform both back-to-back measurements and transmission over 80 km of standard single-mode fiber. Successful self-homodyne detection of all 50 data channels in the 10-nm-wide superchannel demonstrates that the spectral coherence from frequency combs, combined with the use of optical pilots, can overcome limitations arising from frequency offset and phase noise in high-order QAM transmission while keeping the pilot overhead low.
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| 10. |
- 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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