Coating eliminates crosstalk and shrinks waveguides

　　A way to simultaneously control diverse optical properties of dielectric waveguides by using a quasi 2D two-layer coating has been found by a team of Penn State electrical engineers.

　　“Waveguides are an essential component in any electromagnetic or optical system,but they are often overlooked because much of the focus has been on the devices themselves and not the waveguides,"said Chair Professor Genevieve McCain.

　　The researchers developed a material they claim is so thin it is almost 2D,with characteristics that manipulate and enhance properties of the waveguide.

　　The material is said to be composed of two conformal coatings,one for guiding the signal and one to cloak the waveguide,that were then applied to a rod-shaped,Teflon waveguide.

　　By engineering the patterning on the coatings'surfaces,the team could control waveguide functionality and the cloaking coating is said to eliminate crosstalk and blockage.

　　The researchers also claim the effectiveness of the coating can be well maintained for waveguide bends by properly matching the dispersion properties of the metasurface unit cells.Although the coating can be applied to a bend in the waveguide,the waveguide cannot be bent after the coating is applied.

　　Improving the properties of the waveguide to control polarisation and other attributes is said to allow the waveguides to be smaller,and alleviating crosstalk allows these smaller waveguides to be more closely bundled.

　　"In terms of applications,these would include millimetre-wave/terahertz/infrared systems for sensing,communications,and imaging that need to manipulate polarisation,squeeze signals through waveguides with a smaller cross-section,and/or require dense deployment of interconnected components,"said postdoctoral fellow Zhi Hao Jiang.