| 11. |
- 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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| 12. |
- Lundberg, Lars, 1989, et al.
(författare)
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Power Consumption of Hybrid EDFA/Raman Amplified Systems
- 2015
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Ingår i: 41st European Conference on Optical Communication, ECOC 2015, Valencia, Spain, 27 September 2015 - 1 October 2015. - 9788460817413 ; 2015-November
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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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| 13. |
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| 14. |
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| 15. |
- Mazur, Mikael, 1990, et al.
(författare)
-
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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| 16. |
- 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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| 17. |
- 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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| 18. |
- Mazur, Mikael, 1990, et al.
(författare)
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Experimental Investigation of Link Impairments in Pilot Tone Aided Superchannel Transmission
- 2019
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 31:6, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the performance of single-pilot-tone locked frequency comb-based superchannel transmission for distances up to 1200km. In our scheme, electro-optic transmitter and receiver combs are locked by leaving one of the transmitter carriers unmodulated and regenerating the receiver comb via optical injection locking. This approach significantly reduces carrier offsets and therefore leads to reduced digital signal processing complexity. We experimentally assess how transmission impairments such as noise added by optical amplifiers and fiber nonlinearities affect the quality of the comb regeneration. Our results show that while the operating conditions are more stringent at longer distances, the single pilot is robust to impairments. At optimal launch power, similar performance with respect to an intradyne receiver is observed, showing that the optical pilot tones can be co-transmitted with data channels even at distances spanning hundreds of kilometer. The total superchannel spectral efficiency (throughput), including the pilot tone and guardbands, is 9.6 bits/s/Hz (12 Tbit/s) after 480 km and 8.4 bits/s/Hz (10.5 Tbit/s) after 960km.
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| 19. |
- Mazur, Mikael, 1990, et al.
(författare)
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Frequency comb based high-spectral efficiency transmission
- 2019
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Ingår i: Optics InfoBase Conference Papers. - 2162-2701. ; Part F137-SPPCom 2019
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Konferensbidrag (refereegranskat)abstract
- We review our work on high spectral efficiency frequency Comb-Based superchannels using shared optical pilot tones combined with digital signal processing. The coherence of frequency combs is exploited to minimize the pilot tone overhead.
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| 20. |
- Mazur, Mikael, 1990, et al.
(författare)
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High Spectral efficiency PM-128QAM Comb-Based Superchannel Transmission Enabled by a Single Shared Optical Pilot Tone
- 2018
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 36:6, s. 1318-1325
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Tidskriftsartikel (refereegranskat)abstract
- We exploit the coherence of frequency combs for high spectral efficiency superchannel transmission via effective sharing of a single pilot tone. By phase-locking the receiver comb to the transmitted pilot tone, carrier offsets are suppressed while both the overhead and complexity associated with the pilot tone are reduced. We form a 55 carrier superchannel using a 25-GHz spaced electro-optic frequency comb seeded by a 100-kHz linewidth laser. At a pilot tone overhead of <2%, the reduction in carrier offsets is shown to facilitate blind DSP-based carrier recovery of all 54 × 24 Gbaud PM-128QAM data channels. The resulting superchannel spectral efficiency is 10.3 bits/s/Hz assuming a 28% overhead for forward error correction. Our results show the potential for optical pilot tones to reduce both overhead and complexity in systems using comb-based superchannels together with high-order modulation formats.
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