In- and out-coupling of light in photonic-crystal and conventional dielectric waveguides of arbitrary width

A new approach for light coupling between wire dielectric and photonic crystal waveguides, is investigated to optimize the transmission spectrum around 1550 nm. The approach is successfully proposed for input and output coupling with waveguides of arbitrary width, even much larger than the single line defect photonic crystal waveguide. It is shown that the displacement across the interface of the inner hole rows of the photonic crystal waveguide considerably enhances the coupling, resulting in transmission values higher than 90% over bandwidths of hundreds of nanometers.