The design of application-specific integrated circuit (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. We firstly report the key-building blocks of high-speed modern DSP-based transponders working up to 800G per wave. Secondly, 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).
Drug residues, organic dyes, heavy metals, and other chemical pollutants not only cause environmental pollution, but also have a serious impact on food safety. Timely and systematic summary of the latest scientific advances is of great importance for the development of new detection technologies. In particular, molecularly imprinted polymers (MIPs) can mimic antibodies, enzymes and other biological molecules to recognize, enrich, and separate contaminants, with specific recognition, selective adsorption, high affinity, and strong resistance characteristics. Therefore, MIPs have been widely used in chemical analysis, sensing, and material adsorption. In this review, we first describe the basic principles and production processes of molecularly imprinted polymers. Secondly, an overview of recent applications of molecularly imprinted polymers in sample pre-treatment, sensors, chromatographic separation, and mimetic enzymes is highlighted. Finally, a brief assessment of current technical issues and future trends in molecularly imprinted polymers is also presented.
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.
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