Based on the theory of one-dimensional photonic crystal,an asymmetrical interleaver filter composed of thin-film glass cavities is designed.Three thin-film glass cavities are cascaded in the structure.Each cavity is formed by evaporating several layers of reflecting films on two surfaces of the glass medium.Compared with other proposed structures,this interleaver filter is very simple and easy to realize,and it has flat passband and stopband.A design example of a 50 GHz interleaver filter with the duty cycle of 1:5 is presented.The influence of the structural parameters of each reflecting film(including the glass cavity) on the spectral performance is discussed.And the design results with duty cycles of 1:3 and 1:4 are also shown and analyzed.
The double Rayleigh backscatter (DRB) effect in long distance CATV systems using fiber Raman amplifiers (FRAs) is investigated theoretically in the paper. As a comparison, performance of a system with erbium doped fiber amplifier (EDFA) is also evaluated. According to the simulation results, it is found that, in case of FRA, the increase of carrier-to-noise ratio (CNR) due to the DRB effect will not impair the performance more than that using EDFA.
The expectations for sensor networks are growing.The performance of wireless sensor networks(WSNs) is greatly influenced by their network topology.In this paper,we consider four patterned topologies that best support connectivity among these deployed sensor nodes in two-tiered WSNs.The theoretical and simulation results show that the triangle-based topology has smaller cell number,shorter maximum hop length,less total energy consumption,and better performance than other topologies.The analysis carried out in this paper could provide the guidelines for network deployment and protocol design in the future applications.
