Low-latency wavelength-switched clock-synchronized intra-data center interconnects enabled by hollow core fiber.

Fast (nanoseconds) optical wavelength switching is emerging as a viable solution to scaling the size and capacity of intra-data center interconnection. A key enabling technology for such systems is low-jitter optical clock synchronization, which enables sub-nanosecond clock and data recovery for optically switched frames using low-cost methods such as clock phase caching. We propose and demonstrate real-time low-latency wavelength-switched clock-synchronized intra-data center interconnection at 51.2 GBd using a fast tunable laser (with ns scale switching time) and ultra-stable-latency hollow core fiber (HCF) for optically-switched data center networks. For wavelength-switched systems, we achieve a physical layer latency below 46 ns, consisting of 28 ns transceiver latency and a 18 ns inter-packet gap. Finally, we show that by exploiting the low chromatic dispersion and thermally-stable latency features of HCF, active clock phase tracking can be entirely eliminated.

Synchronization issue of coupled neural networks based on flexible impulse control.

The global exponential synchronization issue of coupled neural networks with time-delayed impulses is investigated in this paper. On the basis of the characteristics of coupled neural networks and theorems, we have built a novel coupled systems model. In order to fit the real situation, the impulses are flexible and it can beyond the impulsive interval under certain conditions in this paper. Therefore, our results are less restrictive and more practical compared to existing research. Besides, by using average impulsive delay (AID) and average impulsive interval (AII), we investigate two different effects of impulses on synchronization respectively and get a few adequate conditions for different types of synchronization. Finally, there are two examples of numerical simulations presented to illustrate the efficiency of the conclusions.

Phase noise of electro-optic dual frequency combs.

Dual frequency combs are emerging as new tools for spectroscopy and signal processing. The relative phase noise of the tone pairs determines the performance (e.g., signal-to-noise ratio) of the detected spectral components. Although previous research has shown that the signal quality generally degrades with an increase in frequency difference between tone pairs, the scaling of the relative phase noise of dual frequency comb systems has not been fully characterized. In this Letter, we model and characterize the phase noise of a coherent electro-optic dual frequency comb system. Our results show that at high offset frequencies, the phase noise is an incoherent sum of the timing phase noise of the two combs, multiplied by line number. At low offset frequencies, however, the phase noise scales more slowly due to the coherence of the common frequency reference.