| 1. |
- Pang, Xiaodan, Dr., et al.
(author)
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Bridging the Terahertz Gap : Photonics-assisted Free-Space Communications from the Submillimeter-Wave to the Mid-Infrared
- 2022
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In: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers Inc.. - 0733-8724 .- 1558-2213. ; 40:10, s. 3149-3162
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Journal article (peer-reviewed)abstract
- Since about one and half centuries ago, at the dawn of modern communications, the radio and the optics have been two separate electromagnetic spectrum regions to carry data. Differentiated by their generation/detection methods and propagation properties, the two paths have evolved almost independently until today. The optical technologies dominate the long-distance and high-speed terrestrial wireline communications through fiber-optic telecom systems, whereas the radio technologies have mainly dominated the short- to medium-range wireless scenarios. Now, these two separate counterparts are both facing a sign of saturation in their respective roadmap horizons, particularly in the segment of free-space communications. The optical technologies are extending into the mid-wave and long-wave infrared (MWIR and LWIR) regimes to achieve better propagation performance through the dynamic atmospheric channels. Radio technologies strive for higher frequencies like the millimeter-wave (MMW) and sub-terahertz (sub-THz) to gain broader bandwidth. The boundary between the two is becoming blurred and intercrossed. During the past few years, we witnessed technological breakthroughs in free-space transmission supporting very high data rates, many achieved with the assistance of photonics. This paper focuses on such photonics-assisted free-space communication technologies in both the lower and upper sides of the THz gap and provides a detailed review of recent research and development activities on some of the key enabling technologies. Our recent experimental demonstrations of high-speed free-space transmissions in both frequency regions are also presented as examples to show the system requirements for device characteristics and digital signal processing (DSP) performance.
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| 2. |
- Lu, Yang, et al.
(author)
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Matrix Receiving Scheme Supporting Arbitrary Multiple-Wavelength Reception for Optical Interconnects
- 2017
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In: European Conference on Optical Communication, ECOC. - : IEEE. - 9781538656242
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Conference paper (peer-reviewed)abstract
- An arbitrary multiple-wavelength reception scheme using only a few fixed-wavelength filters is proposed for optical interconnects. Filter matrices design based on error-control coding theory is devised. The feasibility of the proposed scheme is demonstrated in a four-wavelength reception experiment.
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| 3. |
- Pang, Xiaodan, Dr., et al.
(author)
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Free-Space Communications Enabled by Quantum Cascade Lasers
- 2021
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In: Physica Status Solidi (a) applications and materials science. - : Wiley-VCH Verlag. - 1862-6300 .- 1862-6319. ; 218:3
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Journal article (peer-reviewed)abstract
- Future generations of wireless communication systems are expected to support orders of magnitude faster data transfer with much lower latency than the currently deployed solutions. Development of wireless transceivers of higher bandwidth, low energy consumption, and small footprint becomes challenging with radio frequency (RF) electronic technologies. Photonics-assisted technologies show many advantages in generating signals of ultrabroad bandwidth at high carrier frequencies in the millimeter-wave, terahertz, and IR bands. Among these frequency options, the mid-IR band has recently attracted great interest for future wireless communication due to its intrinsic merits of low propagation loss and high tolerance of atmospheric perturbations. A promising source for mid-IR free-space communications is the semiconductor quantum cascade laser (QCL), which can be directly modulated at a high speed and facilitates monolithic integration for compact transceivers. Herein, the research and development of QCL-based free-space communications are reviewed and a recent experimental study of multi-gigabit transmission with a directly modulated mid-IR QCL and a commercial off-the-shelf IR photodetector is reported on. Up to 4 Gb s−1 transmission of two advanced modulation formats, namely, four-level pulse amplitude modulation (PAM-4) and discrete multitone (DMT) modulation, is demonstrated. © 2020 The Authors.
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| 4. |
- Li, Jun, et al.
(author)
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Service Migration in Fog Computing Enabled Cellular Networks to Support Real-Time Vehicular Communications
- 2019
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 7, s. 13704-13714
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Journal article (peer-reviewed)abstract
- Driven by the increasing number of connected vehicles and related services, powerful communication and computation capabilities are needed for vehicular communications, especially for real-time and safety-related applications. A cellular network consists of radio access technologies, including the current long-term evolution (LTE), the LTE advanced, and the forthcoming 5th generation mobile communication systems. It covers large areas and has the ability to provide high data rate and low latency communication services to mobile users. It is considered the most promising access technology to support real-time vehicular communications. Meanwhile, fog is an emerging architecture for computing, storage, and networking, in which fog nodes can be deployed at base stations to deliver cloud services close to vehicular users. In fog computing-enabled cellular networks, mobility is one of the most critical challenges for vehicular communications to maintain the service continuity and to satisfy the stringent service requirements, especially when the computing and storage resources are limited at the fog nodes. Service migration, relocating services from one fog server to another in a dynamic manner, has been proposed as an effective solution to the mobility problem. To support service migration, both computation and communication techniques need to be considered. Given the importance of protocol design to support the mobility of the vehicles and maintain high network performance, in this paper, we investigate the service migration in the fog computing-enabled cellular networks. We propose a quality-of-service aware scheme based on the existing handover procedures to support the real-time vehicular services. A case study based on a realistic vehicle mobility pattern for Luxembourg scenario is carried out, where the proposed scheme, as well as the benchmarks, are compared by analyzing latency and reliability as well as migration cost.
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| 5. |
- Lin, Rui, 1988, et al.
(author)
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Telecommunication compatibility evaluation for co-existing quantum key distribution in homogenous multicore fiber
- 2020
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers Inc.. - 2169-3536. ; 8, s. 78836-78846
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Journal article (peer-reviewed)abstract
- Quantum key distribution (QKD) is regarded as an alternative to traditional cryptography methods for securing data communication by quantum mechanics rather than computational complexity. Towards the massive deployment of QKD, embedding it with the telecommunication system is crucially important. Homogenous optical multi-core fibers (MCFs) compatible with spatial division multiplexing (SDM) are essential components for the next-generation optical communication infrastructure, which provides a big potential for co-existence of optical telecommunication systems and QKD. However, the QKD channel is extremely vulnerable due to the fact that the quantum states can be annihilated by noise during signal propagation. Thus, investigation of telecom compatibility for QKD co-existing with high-speed classical communication in SDM transmission media is needed. In this paper, we present analytical models of the noise sources in QKD links over heterogeneous MCFs. Spontaneous Raman scattering and inter-core crosstalk are experimentally characterized over spans of MCFs with different refractive index profiles, emulating shared telecom traffic conditions. Lower bounds for the secret key rates and quantum bit error rate (QBER) due to different core/wavelength allocation are obtained to validate intra- and inter-core co-existence of QKD and classical telecommunication
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| 6. |
- Lu, Yang, et al.
(author)
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Multi-channel collision-free reception for optical interconnects
- 2018
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In: Optics Express. - : OPTICAL SOC AMER. - 1094-4087. ; 26:10, s. 13214-13222
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Journal article (peer-reviewed)abstract
- A multi-channel reception scheme that allows each node to receive an arbitrary set of wavelengths simultaneously (i.e., collision-free) is proposed for optical interconnects. The proposed scheme only needs to use a few receivers and fixed-wavelength filters that are designed based on error-control coding theory. Experiments with up to four channel collision-free reception units are carried out to demonstrate the feasibility of the proposed scheme.
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| 7. |
- Zhang, Lu, et al.
(author)
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Toward terabit digital radio over fiber systems : Architecture and key technologies
- 2019
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In: IEEE Communications Magazine. - : Institute of Electrical and Electronics Engineers Inc.. - 0163-6804 .- 1558-1896. ; 57:4, s. 131-137
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Journal article (peer-reviewed)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.
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| 8. |
- Jia, Shi, et al.
(author)
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Integrated dual-laser photonic chip for high-purity carrier generation enabling ultrafast terahertz wireless communications
- 2022
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Journal article (peer-reviewed)abstract
- Photonic generation of Terahertz (THz) carriers displays high potential for THz communications with a large tunable range and high modulation bandwidth. While many photonics-based THz generations have recently been demonstrated with discrete bulky components, their practical applications are significantly hindered by the large footprint and high energy consumption. Herein, we present an injection-locked heterodyne source based on generic foundry-fabricated photonic integrated circuits (PIC) attached to a uni-traveling carrier photodiode generating high-purity THz carriers. The generated THz carrier is tunable within the range of 0-1.4 THz, determined by the wavelength spacing between the two monolithically integrated distributed feedback (DFB) lasers. This scheme generates and transmits a 131 Gbits(-1) net rate signal over a 10.7-m distance with -24 dBm emitted power at 0.4 THz. This monolithic dual-DFB PIC-based THz generation approach is a significant step towards fully integrated, cost-effective, and energy-efficient THz transmitters. A photonic Terahertz source based on injection-locking an integrated dual-laser chip generates and transmits a 131 Gbps THz signal over 10.7-m distance, showing great potential towards fully integrated and energy-efficient THz transmitters for 6G.
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| 9. |
- Jia, S., et al.
(author)
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Integrated Dual-DFB Laser for 408 GHz Carrier Generation Enabling 131 Gbit/s Wireless Transmission over 10.7 Meters
- 2019
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In: 2019 Optical Fiber Communications Conference and Exhibition, OFC 2019 - Proceedings. - Washington, D.C. : Institute of Electrical and Electronics Engineers Inc.. - 9781943580538
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Conference paper (peer-reviewed)abstract
- A monolithically integrated dual-DFB laser generates a 408 GHz carrier used for demonstrating a record-high single-channel bit rate of 131 Gbit/s transmitted over 10.7 m. 16-QAM-OFDM modulation and specific nonlinear equalization techniques are employed
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| 10. |
- Ozolins, Oskars, et al.
(author)
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Invited Speech Single Lane 200 Gbps Transmitter for IM/DD Links
- 2018
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In: Proceedings - 2018 Advances in Wireless and Optical Communications, RTUWO 2018. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538655580
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Conference paper (peer-reviewed)abstract
- Provides an abstract of the keynote presentation and may include a brief professional biography of the presenter. The complete presentation was not made available for publication as part of the conference proceedings.
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