Compact three-port optical two-dimensional photonic crystal-based circulator of W-format.

A three-port optical circulator of W-format based on 2D photonic crystal is presented. This circulator is more compact as compared to the known one of the traditional Y-format. The W-circulator does not have rotational symmetry. As a consequence, the frequency responses for different port excitation are slightly different, as it is shown by symmetry analysis and by numerical simulations.