| 1. |
- Feng, Zhenhua, et al.
(author)
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Multicore-Fiber-Enabled WSDM Optical Access Network With Centralized Carrier Delivery and RSOA-Based Adaptive Modulation
- 2015
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In: IEEE PHOTONICS JOURNAL. - : Institute of Electrical and Electronics Engineers (IEEE). - 1943-0655. ; 7:4
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Journal article (peer-reviewed)abstract
- We proposed and experimentally demonstrated a wavelength-space division multiplexing (WSDM) optical access network architecture with centralized optical carrier delivery utilizing multicore fibers (MCFs) and adaptive modulation based on reflective semiconductor amplifier (RSOA). In our experiment, five of the outer cores are used for undirectional downstream (DS) transmission only, whereas the remaining outer core is utilized as a dedicated channel to transmit upstream (US) signals. Optical carriers for US are delivered from the optical line terminal (OLT) to the optical network unit (ONU) via the inner core and then transmitted back to the OLT after amplification and modulation by the RSOA in the colorless ONU side. The mobile backhaul (MB) service is also supported by the inner core. Wavelengths used in US transmission should be different from that of the MB in order to avoid the Rayleigh backscattering effect in bidirectional transmission. With quadrature phase-shift keying-orthogonal frequency-division multiplexing (QPSK-OFDM) modulation format, the aggregation DS capacity reaches 250 Gb/s using five outer cores and ten wavelengths, and it can be further scaled to 1 Tb/s using 20 wavelengths modulated with 16 QAM-OFDM. For US transmission, 2.5 Gb/s QPSK-OFDM transmission can be achieved just using a low-bandwidth RSOA, and adaptive modulation is applied to the RSOA to further enhance the US data rate to 3.12 Gb/s. As an emulation of high-speed MB transmission, 48 Gb/s inphase and quadrature (IQ) modulated popularization division multiplexing (PDM)-QPSK signal is transmitted in the inner core of MCF and coherently detected in the OLT side. Both DS and US optical signals exhibit acceptable performance with sufficient power budget.
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| 2. |
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- 2019
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Journal article (peer-reviewed)
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| 3. |
- Blösch, Günter, et al.
(author)
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Twenty-three unsolved problems in hydrology (UPH) - a community perspective
- 2019
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In: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 64:10, s. 1141-1158
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Journal article (peer-reviewed)abstract
- This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come.
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| 4. |
- Feng, Z., et al.
(author)
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Terabit WSDM optical access network using multicore fibers and advanced modulation formats
- 2015
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Conference paper (peer-reviewed)abstract
- We proposed a hybrid wavelength-space division multiplexing (WSDM) optical access network architecture utilizing multicore fibers (MCFs) with advanced modulation formats. As a proof of concept, we experimentally demonstrated a WSDM optical access network with duplex transmission using our developed and fabricated multicore (7-core) fibers and fan-in/fan-out device with 58.7km distance. With QPSK-OFDM modulation format, the aggregation downstream (DS) capacity reaches 250 Gb/s using 5 outer cores and it can be further scaled to 1Tb/s using 16QAM-OFDM. For upstream (US) transmission, wavelengths seeded from DS using the inner core are modulated with DMT signal adapted with the channel conditions and then transmitted back to the OLT through the 6th outer core. As an emulation of high speed mobile backhaul (MB) transmission, IQ modulated PDM-QPSK signal with 48Gb/s per wavelength is transmitted in the inner core of MCF and coherently detected in the OLT side. Both DS and US optical signal exhibit acceptable performance with sufficient power budget.
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| 5. |
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| 6. |
- Kerrebrouck, Joris Van, et al.
(author)
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726.7-Gb/s 1.5-μm single-mode VCSEL discrete multi-tone transmission over 2.5-km multicore fiber
- 2018
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In: 2018 Optical Fiber Communications Conference and Exposition, OFC 2018 - Proceedings. - : Institute of Electrical and Electronics Engineers Inc.. - 9781943580385 ; , s. 1-3
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Conference paper (peer-reviewed)abstract
- A 107Gb/s net-rate DMT optical signal was generated using a single-mode long-wavelength VCSEL with a modulation bandwidth of 23 GHz. We experimentally demonstrated a total net-rate up to 726.7Gb/s at 1.5μm over 2.5km 7-core dispersion-uncompensated MCF.
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| 7. |
- Kerrebrouck, Joris Van, et al.
(author)
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High-speed PAM4-based Optical SDM Interconnects with Directly Modulated Long-wavelength VCSEL
- 2019
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In: Journal of Lightwave Technology. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0733-8724 .- 1558-2213. ; 37:2, s. 356-362
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Journal article (peer-reviewed)abstract
- This paper reports the demonstration of high-speed PAM-4 transmission using a 1.5-μm single-mode vertical cavity surface emitting laser (SM-VCSEL) over multicore fiber with 7 cores over different distances. We have successfully generated up to 70 Gbaud 4-level pulse amplitude modulation (PAM-4) signals with a VCSEL in optical back-to-back, and transmitted 50 Gbaud PAM-4 signals over both 1-km dispersion-uncompensated and 10-km dispersion-compensated in each core, enabling a total data throughput of 700 Gbps over the 7-core fiber. Moreover, 56 Gbaud PAM-4 over 1-km has also been shown, whereby unfortunately not all cores provide the required 3.8 × 10$^-3$bit error rate (BER) for the 7% overhead-hard decision forward error correction (7% OH HDFEC). The limited bandwidth of the VCSEL and the adverse chromatic dispersion of the fiber are suppressed with pre-equalization based on accurate end-to-end channel characterizations. With a digital post-equalization, BER performance below the 7% OH-HDFEC limit is achieved over all cores. The demonstrated results show a great potential to realize high-capacity and compact short-reach optical interconnects for data centers.
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| 8. |
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| 9. |
- Lin, Rui, et al.
(author)
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Real-time 100 Gbps/lambda/core NRZ and EDB IM/DD Transmission over 10 km Multicore Fiber
- 2018
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In: 2018 Optical Fiber Communications Conference and Exposition (OFC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781943580385 ; , s. 1-3
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Conference paper (peer-reviewed)abstract
- A BiCMOS chip-based real-time IM/DD spatial division multiplexing system is experimentally demonstrated for short-reach communications. 100 Gbps/λ/core NRZ and EDB transmission is achieved below 7%-overhead HD-FEC limit after 10km 7-core fiber with optical dispersion compensation.
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| 10. |
- Lin, Rui, et al.
(author)
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Real-time 100 Gbps/λ/core NRZ and EDB IM/DD transmission over multicore fiber for intra-datacenter communication networks
- 2018
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In: Optics Express. - : OSA - The Optical Society. - 1094-4087. ; 26:8, s. 10519-10526
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Journal article (peer-reviewed)abstract
- A BiCMOS chip-based real-time intensity modulation/direct detection spatial division multiplexing system is experimentally demonstrated for both optical interconnects. 100 Gbps/λ/core electrical duobinary (EDB) transmission over 1 km 7-core multicore fiber (MCF) is carried out, achieving KP4 forward error correction (FEC) limit (BER < 2E-4). Using optical dispersion compensation, 7 × 100 Gbps/λ/core transmission of both non-return-to-zero (NRZ) and EDB signals over 10 km MCF transmission is achieved with BER lower than 7% overhead hard-decision FEC limit (BER < 3.8E-3). The integrated low complexity transceiver IC and analog signal processing approach make such a system highly attractive for the high-speed intra-datacenter interconnects..
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