Worldwide electricity consumption of communication networks.

There is a growing research interest in improving the energy efficiency of communication networks. In order to assess the impact of introducing new energy efficient technologies, an up-to-date estimate for the global electricity consumption in communication networks is needed. In this paper we consider the use phase electricity consumption of telecom operator networks, office networks and customer premises equipment. Our results show that the network electricity consumption is growing fast, at a rate of 10 % per year, and its relative contribution to the total worldwide electricity consumption has increased from 1.3% in 2007 to 1.8% in 2012. We estimate the worldwide electricity consumption of communication networks will exceed 350 TWh in 2012.

Trimming of silicon-on-insulator ring resonators with a polymerizable liquid crystal cladding.

We demonstrate the trimming of silicon-on-insulator ring resonators with a cladding layer of polymerizable liquid crystal. An electric field is applied over the cladding layer to tune the resonance of the ring resonators, which is then fixed by UV illumination of the polymerizable liquid crystal. A range of 0.56 nm is obtained. We provide the material properties of the polymerizable liquid crystal, give a description of the tuning mechanism and present experimental results. This method opens up possibilities in the field of low-cost trimming of photonic devices.