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Author

Yuliang Gao

Bio: Yuliang Gao is an academic researcher from Northeastern University (China). The author has contributed to research in topics: Quadrature amplitude modulation & Modulation. The author has an hindex of 16, co-authored 55 publications receiving 1087 citations. Previous affiliations of Yuliang Gao include McGill University & Hong Kong Polytechnic University.

Papers published on a yearly basis

Papers
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Journal ArticleDOI
TL;DR: A detailed investigation on the performance of three advanced modulation formats for 100 Gb/s short reach transmission system, PAM-4, CAP-16 and DMT, and a comparison of computational complexity of DSP for the three formats is presented.
Abstract: Advanced modulation formats combined with digital signal processing and direct detection is a promising way to realize high capacity, low cost and power efficient short reach optical transmission system. In this paper, we present a detailed investigation on the performance of three advanced modulation formats for 100 Gb/s short reach transmission system. They are PAM-4, CAP-16 and DMT. The detailed digital signal processing required for each modulation format is presented. Comprehensive simulations are carried out to evaluate the performance of each modulation format in terms of received optical power, transmitter bandwidth, relative intensity noise and thermal noise. The performance of each modulation format is also experimentally studied. To the best of our knowledge, we report the first demonstration of a 112 Gb/s transmission over 10km of SSMF employing single band CAP-16 with EML. Finally, a comparison of computational complexity of DSP for the three formats is presented.

274 citations

Journal ArticleDOI
TL;DR: This manuscript discusses the motivations for jointly utilizing transmission techniques such as probabilistic shaping and digital sub-carrier multiplexing in digital coherent optical transmissions systems and describes the key-building blocks of modern high-speed DSP-based transponders working at up to 800G per wave.
Abstract: The design of application-specific integrated circuits (ASIC) is at the core of modern ultra-high-speed transponders employing advanced digital signal processing (DSP) algorithms. This manuscript discusses the motivations for jointly utilizing transmission techniques such as probabilistic shaping and digital sub-carrier multiplexing in digital coherent optical transmissions systems. First, we describe the key-building blocks of modern high-speed DSP-based transponders working at up to 800G per wave. Second, we show the benefits of these transmission methods in terms of system level performance. Finally, we report, to the best of our knowledge, the first long-haul experimental transmission – e.g., over 1000 km – with a real-time 7 nm DSP ASIC and digital coherent optics (DCO) capable of data rates up to 1.6 Tb/s using two waves (2 × 800G).

181 citations

Journal ArticleDOI
TL;DR: It is shown experimentally that the SCM signal with a nearly-optimum number of subcarriers can extend the maximum reach by 23% in a 24 GBaud DP-QPSK transmission with a BER threshold, further indicating the merits of SCM signals in baud-rate flexible agile transmissions and future high-speed optical transport systems.
Abstract: In this work we experimentally investigate the improved intra-channel fiber nonlinearity tolerance of digital subcarrier multiplexed (SCM) signals in a single-channel coherent optical transmission system. The digital signal processing (DSP) for the generation and reception of the SCM signals is described. We show experimentally that the SCM signal with a nearly-optimum number of subcarriers can extend the maximum reach by 23% in a 24 GBaud DP-QPSK transmission with a BER threshold of 3.8 × 10−3 and by 8% in a 24 GBaud DP-16-QAM transmission with a BER threshold of 2 × 10−2. Moreover, we show by simulations that the improved performance of SCM signals is observed over a wide range of baud rates, further indicating the merits of SCM signals in baud-rate flexible agile transmissions and future high-speed optical transport systems.

124 citations

Journal ArticleDOI
TL;DR: A detailed investigation on the digital filters in CAP modulation system is presented and the feasibility of the CAP16 modulation for the short range transmission systems is demonstrated experimentally.
Abstract: Carrier-less amplitude and phase (CAP) modulation can be a good candidate for short range optical communications for considerable computational complexity reduction and simple system structure. In this paper, a detailed investigation on the digital filters in CAP modulation system is presented. An adaptive equalizer based on cascaded multi-modulus algorithm (CMMA) is used for the demodulation at the receiver. The impact of digital filter taps on system performance is investigated through comprehensive simulations and a 10 Gb/s CAP16 modulation system is demonstrated experimentally. The BER performance for different length of fiber link is measured. Compared with back-to-back (BTB) transmissions, 2 dB and 3.5 dB receiver power penalty are observed at BER of 10(-3) for 20 km and 40 km fiber link respectively. It clearly demonstrates the feasibility of the CAP16 modulation for the short range transmission systems.

91 citations

Journal ArticleDOI
TL;DR: In this article, the authors experimentally demonstrated 140-Gb/s transmission over 20-km standard single-mode fiber employing PAM-4 and direct detection (DD) at 1.3 $\mu \text{m}$.
Abstract: We experimentally demonstrated 140-Gb/s transmission over 20-km standard single-mode fiber employing pulse-amplitude modulation (PAM)-4 and direct detection (DD) at 1.3 $\mu \text{m}$ . DD faster than Nyquist is employed to compensate for channel impairments. The optimal length of taps of decision directed least mean square and the optimal tap coefficient for digital postfilter are investigated. A receiver sensitivity of −5.5 dBm at bit error rate of $3.8\times 10^{-3}$ is realized for 140-Gb/s PAM-4 signal after 20-km transmission. To the best of our knowledge, this is the highest reported baud rate (70 GBd) of direct detected PAM-4 signal and the highest per channel bit rate with single polarization and DD for short reach communications.

76 citations


Cited by
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Journal ArticleDOI
TL;DR: An overview of recent DSP developments for short-reach communications systems is presented and future trends are discussed.
Abstract: Driven primarily by cloud service and data-center applications, short-reach optical communication has become a key market segment and growing research area in recent years. Short-reach systems are characterized by direct detection-based receiver configurations and other low-cost and small form factor components that induce transmission impairments unforeseen in their coherent counterparts. Innovative signaling and digital signal processing (DSP) play a pivotal role in enabling these components to realize their ultimate potentials and meet data rate requirements in cost-effective manners. This paper presents an overview of recent DSP developments for short-reach communications systems and discusses future trends.

319 citations

Journal ArticleDOI
TL;DR: A detailed investigation on the performance of three advanced modulation formats for 100 Gb/s short reach transmission system, PAM-4, CAP-16 and DMT, and a comparison of computational complexity of DSP for the three formats is presented.
Abstract: Advanced modulation formats combined with digital signal processing and direct detection is a promising way to realize high capacity, low cost and power efficient short reach optical transmission system. In this paper, we present a detailed investigation on the performance of three advanced modulation formats for 100 Gb/s short reach transmission system. They are PAM-4, CAP-16 and DMT. The detailed digital signal processing required for each modulation format is presented. Comprehensive simulations are carried out to evaluate the performance of each modulation format in terms of received optical power, transmitter bandwidth, relative intensity noise and thermal noise. The performance of each modulation format is also experimentally studied. To the best of our knowledge, we report the first demonstration of a 112 Gb/s transmission over 10km of SSMF employing single band CAP-16 with EML. Finally, a comparison of computational complexity of DSP for the three formats is presented.

274 citations

Journal ArticleDOI
TL;DR: This article comprehensively survey studies that examine the SDN paradigm in optical networks; in brief, it mainly organize the SDON studies into studies focused on the infrastructure layer, the control layer, and the application layer.
Abstract: The emerging software defined networking (SDN) paradigm separates the data plane from the control plane and centralizes network control in an SDN controller. Applications interact with controllers to implement network services, such as network transport with quality of service. SDN facilitates the virtualization of network functions so that multiple virtual networks can operate over a given installed physical network infrastructure. Due to the specific characteristics of optical (photonic) communication components and the high optical transmission capacities, SDN-based optical networking poses particular challenges, but holds also great potential. In this article, we comprehensively survey studies that examine the SDN paradigm in optical networks; in brief, we survey the area of software defined optical networks (SDONs). We mainly organize the SDON studies into studies focused on the infrastructure layer, the control layer, and the application layer. Moreover, we cover SDON studies focused on network virtualization, as well as SDON studies focused on the orchestration of multilayer and multidomain networking. Based on the survey, we identify open challenges for SDONs and outline future directions.

269 citations

Journal ArticleDOI
TL;DR: A comprehensive tutorial on technologies, requirements, architectures, challenges, and potential solutions on means of achieving an efficient C-RAN optical fronthaul for the next-generation network such as the fifth generation network and beyond is presented.
Abstract: The exponential traffic growth, demand for high speed wireless data communications, as well as incessant deployment of innovative wireless technologies, services, and applications, have put considerable pressure on the mobile network operators (MNOs). Consequently, cellular access network performance in terms of capacity, quality of service, and network coverage needs further considerations. In order to address the challenges, MNOs, as well as equipment vendors, have given significant attention to the small-cell schemes based on cloud radio access network (C-RAN). This is due to its beneficial features in terms of performance optimization, cost-effectiveness, easier infrastructure deployment, and network management. Nevertheless, the C-RAN architecture imposes stringent requirements on the fronthaul link for seamless connectivity. Digital radio over fiber-based common public radio interface (CPRI) is the fundamental means of distributing baseband samples in the C-RAN fronthaul. However, optical links which are based on CPRI have bandwidth and flexibility limitations. Therefore, these limitations might constrain or make them impractical for the next generation mobile systems which are envisaged not only to support carrier aggregation and multi-band but also envisioned to integrate technologies like millimeter-wave (mm-wave) and massive multiple-input multiple-output antennas into the base stations. In this paper, we present comprehensive tutorial on technologies, requirements, architectures, challenges, and proffer potential solutions on means of achieving an efficient C-RAN optical fronthaul for the next-generation network such as the fifth generation network and beyond. A number of viable fronthauling technologies such as mm-wave and wireless fidelity are considered and this paper mainly focuses on optical technologies such as optical fiber and free-space optical. We also present feasible means of reducing the system complexity, cost, bandwidth requirement, and latency in the fronthaul. Furthermore, means of achieving the goal of green communication networks through reduction in the power consumption by the system are considered.

263 citations

Journal ArticleDOI
TL;DR: The development of various OPM techniques for direct-detection systems and digital coherent systems are reviewed and future OPM challenges in flexible and elastic optical networks are discussed.
Abstract: Optical performance monitoring (OPM) is the estimation and acquisition of different physical parameters of transmitted signals and various components of an optical network. OPM functionalities are indispensable in ensuring robust network operation and plays a key role in enabling flexibility and improve overall network efficiency. We review the development of various OPM techniques for direct-detection systems and digital coherent systems and discuss future OPM challenges in flexible and elastic optical networks.

242 citations