| 26. |
- Udalcovs, Aleksejs, et al.
(författare)
-
Inter-Core Crosstalk in Multicore Fibers: Impact on56−Gbaud/λ /Core PAM-4 Transmission
- 2018
-
Ingår i: 2018 European Conference on Optical Communication (ECOC). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate the impact of inter-core crosstalk in multicore fibers on 56-Gbaud PAM-4 signal quality after 2.5-km transmission over a weakly-coupled and uncoupled seven-core fibers, revealing the crosstalk dependence on carrier central wavelength in range of 1540-1560 nm.
|
|
| 27. |
- Udalcovs, Aleksejs, et al.
(författare)
-
Towards Coherent Detection in SDM-based Optical Access Networks
- 2018
-
Konferensbidrag (refereegranskat)abstract
- To tackle the continued increase in capacity demand in optical access, self-homodyne coherent detection (SHCD) is being considered as a candidate solution, utilizing a spatial division multiplexing (SDM) in a low-crosstalk multicore fiber (MCF) [1, 2] and high-order modulation formats such as quadrature phase-shift keying (QPSK), 16-levels quadrature amplitude modulation (16-QAM) or even 64-levels QAM (64-QAM) . The latest imposes strict requirements on both the performance of digital signal processing (DSP) and the spectral purity of the free running lasers [4–6]. Although a SHCD scheme relaxes the laser linewidth requirements, eliminates the need for a carrier frequency tracking, the necessity for a carrier phase estimation remains if high-order constellations are considered. The reasons for that are (1) residual phase noise in a system and (2) a closer location of the constellation points in the complex plane, which leads to a significantly lower phase noise tolerance as compared to QPSK or even 16-QAM signals . Therefore, it is of crucial importance to propose a low-complexity (and low-latency) phase estimation algorithms for these scenarios as well, especially because traditional algorithms cannot be directly employed for 64QAM. During this presentation,first, we overview our recent activities on designing and experimental validation of a high-performance and a low-complexity DSP block, focusing on carrier phase recovery (CPR) suitable for circular and square m-QAM constellations. For more information about the efficient CPR schemes for m-QAM, we recommend theOFC2017 and ACP2017 proceedings.Second, after the efficient CPR scheme is explained, we provide an insight into a solution of SDM-based optical access network where self-homodyne coherent detection (SHCD) scheme with our novel low-complexity CPR is implemented for a 28-Gbaud 16-QAM and 64- QAM transmission in downstream links with a goal to improve their spectral efficiency and to increase a phase-noise tolerance, which paves the way towards higher cost-efficiency. The proposed architecture together with the experimental demonstration is given inCLEO2018 conference proceedings
|
|
| 28. |
- Zhang, Lu, et al.
(författare)
-
Digital Radio-Over-Multicore-Fiber System with Self-Homodyne Coherent Detection and Entropy Coding for Mobile Fronthaul
- 2018
-
Ingår i: European Conference on Optical Communication, ECOC. - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate a 28-Gbaud 16-QAM self-homodyne digital radio-over-33.6km-7-core-fiber system with entropy coding for mobile fronthaul, achieving error-free carrier aggregation of 330 100-MHz 4096-QAM 5G-new-radio channels and 921 100-MHz QPSK 5G-new-radio channels with CPRI-equivalent data rate up to 3.73-Tbit/s.
|
|
| 29. |
|
|
| 30. |
- Zhang, Lu, et al.
(författare)
-
Nonlinearity Tolerant High-speed DMT Transmission with 1.5-μm Single-mode VCSEL and Multi-core Fibers for Optical Interconnects
- 2019
-
Ingår i: Journal of Lightwave Technology. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0733-8724 .- 1558-2213. ; 37:2, s. 380-388
-
Tidskriftsartikel (refereegranskat)abstract
- We experimentally demonstrate the generation of 107-Gbit/s net-rate optical discrete multitone (DMT) signal using a 1.5-μm single-mode vertical cavity surface emitting laser (VCSEL) with modulation bandwidth of 22-GHz. Utilizing a nonlinearity-tolerant channel equalization algorithm for digital signal processing (DSP), total net-rates of 726.6-Gbit/s over 2.5-km dispersion-uncompensated 7-core fiber and 533.1-Gbit/s over 10-km dispersion-compensated 7-core fiber below 7% overhead hard-decision forward error correction (HD-FEC) limit have been experimentally achieved with a 1.5-μm VCSEL based intensity-modulation direct-detection (IM/DD) system. The features of the 1.5-μm single-mode VCSEL, 2.5-km/10km multi-core fibers and fan-in/fan-out modules are presented. Besides, the Volterra series based nonlinearity-tolerant channel equalization algorithm, which improves the signal-to-noise ratio (SNR) with more than 5-dB, is mathematically described and experimentally validated. The results have demonstrated that 1.5-μm single-mode VCSEL and multi-core fiber based transmission can be a promising candidate to solve the capacity challenges in short-reach optical interconnects.
|
|
| 31. |
- Zhang, Lu, et al.
(författare)
-
Toward terabit digital radio over fiber systems : Architecture and key technologies
- 2019
-
Ingår i: IEEE Communications Magazine. - : Institute of Electrical and Electronics Engineers Inc.. - 0163-6804 .- 1558-1896. ; 57:4, s. 131-137
-
Tidskriftsartikel (refereegranskat)abstract
- To support massive deployment of broadband radio applications, such as 5G and high-definition videos for terrestrial televisions, large system capacity and high spectrum efficiency are highly demanded in radio over fiber (RoF) systems. In this article, we propose a terabit digital RoF system capable of providing high-speed transmission, where multicore fiber (MCF) is introduced for the access segment between the central unit and remote unit. Two key technologies that greatly enhance system capacity and spectrum efficiency, namely MCF enabled self-homodyne detection and compressed quantization, are demonstrated.
|
|
