Department of Communication, Fudan University, Department of Communication, Fudan University, Ministry of Education Key Laboratory of Electromagnetic Information Science Dr. Zhang Junwen, "National Thousands Plan" Professor Yu Jianjun and Professor Chi Nan et al "Paper based on Sinc Nyquist pulse polarization multiplexing Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses. In a journal Nature Science Group Scientific Report Published in Scientific Reports. This important achievement is another breakthrough in this field following the first successful completion of the full Nyquist signal generation and coherent detection by the research team in 2014. In August 2014, the team published "High Speed ​​All Optical Nyquist Signal Generation and Full-band Coherent Detection" papers published in the Nature Science Report , Started the research of ultra-fast all-optical all-optical signal processing and transmission network. Based on the above results, the research team realized long-distance transmission of polarization-multiplexed all-optical Nyquist signals and successfully realized all-pass 1Tb / s all-optical Nyquist signal coherent detection for the first time. In recent years, with the rapid development of new services such as high-definition Internet TV, multimedia, Internet of Things, smart phones, cloud computing and social media, people have continuously increased demands on network bandwidth or "network speed", and transmission rates of communication and Internet Data traffic has been explosive growth, which puts forward higher transmission performance requirements for the physical layer optical transport network that is the basis of the entire communication system. According to statistics, at present there are 7.5 billion mobile phone users and over 3 billion Internet users in the world. The underlying backbone networks are all based on optical fiber communications. Optical fiber communication has great broadband transmission capacity, and more than 97% of the amount of information in our country is transmitted through optical fibers. From the core backbone network to the metropolitan area network, optical network switching nodes, to the data center optical interconnection, urban optical fiber Access networks and even optical fiber wireless convergence access network, optical fiber communication network has become the infrastructure of national information construction, as well as information transfer and exchange irreplaceable hosting platform. According to statistics, from 1990 to 2014, the global optical communications capacity increased by 600 to 700 times, optical communications transmission capacity increased by a thousand times ten years. Globally, it is estimated that from 2015 to 2018, the global Internet will maintain an annual growth rate of over 30% to 60%. By 2030, more than 1 trillion devices will be connected to the Internet as the Internet and communications network The basic optical transmission network will continue to face the pressure to carry huge amounts of data. Network expansion is imperative. Under this background, the generation of ultra-high-speed ultra-large-capacity and high-spectral-efficiency optical signals has drawn much attention both at home and abroad. In general, the speed and efficiency that a single transceiver can achieve often determines the cost and power consumption of the overall system. Integrated high-speed transceiver equipment, system cost and power consumption can be minimized, so countries and major telecommunications giants in the world are studying how to continuously improve the transmission rate of a single transceiver device within a certain bandwidth. The Nyquist signal has the theoretical minimum signal bandwidth, which is equivalent to compressing a certain signal within the minimum channel window for lossless transmission. In general, Nyquist signals need to be implemented using high-speed analog-to-digital conversion electronics, however, this electrical signal is limited by the bandwidth of the electronics and makes it difficult to achieve high-speed signal generation. All-optical signal processing can break through the bandwidth limitation of electronic devices and greatly improve the signal generation and processing rate. The all-optical Nyquist signal can not only achieve high-speed signal generation but also ensure high spectral efficiency with great application prospect. Therefore, the generation and detection of plenoptic Nyquist signals are widely concerned both at home and abroad. The significance of this research is to increase the transmission capacity of the optical transport network by effectively increasing the rate of a single transceiver to solve the congestion problem of the backbone transport network caused by the explosive growth of network traffic. If you consider voice communications, which is equivalent to a light wave can support 12 million simultaneous calls; and home users use the signal flow 10Mb / s, for example, 1Tb / s backbone transmission rate, then a light wave can support the maximum Users 100,000, and if you continue to consider the 40-way optical fiber inside the usual optical wavelength, then through a hair-sized optical fiber can achieve 40T communications, which also supports 4 million. Nyquist pulse signal can be used with very classic time-frequency transform characteristics. On the time axis, the Nyquist pulse is a series of infinitely stretched signals, making it difficult to produce this perfect waveform digitally. However, on the frequency axis it evolved into a simple, comb-like, limited frequency point. Fudan University research team using all-optical comb makeup, Nyquist signal through the time-frequency conversion characteristics, the first in the frequency domain filter to get the perfect cycle of pulses, and then in the time domain orthogonal multiplexing; at the receiver end, After obtaining the complete information of the signal through all-pass-band coherent detection, the advanced signal processing algorithm is proposed to separate, equalize and reconstruct the pulse signal. Through this method, the first true all-optical Nyquist signal coherent communication system was successively successfully detected, and the generation of polarization-multiplexed all-optical Nyquist signals, long-distance transmission and all-pass coherent detection were successfully achieved, And achieved a record of 1Tb / s single all-optical Nyquist 16QAM signal generation and detection. Scientific Reports is a comprehensive science journal founded by the Nature Publishing Group (NPG) in 2011 and covers a wide range of subjects in the natural sciences. The re-publication of the relevant results of the all-optical Nyquist signal shows that our school constantly makes new breakthroughs in this field. 1.The types of common nail: Common Nail,Common Wire Nail,Common Framing Nails,Bright Common Nails Anping Bochuan Wire Mesh Co., Ltd. , https://www.wiremeshbocn.com
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