A chiral optical waveguide

摘要

An optical waveguide comprises a core (20;30) and is characterised in that the core (20;30) has a refractive index that includes a radial discontinuity (50;55) and varies, with increasing azimuthal angle ¸, from a first value n 2 at a first side of the discontinuity (50;55) to a second value n 1 at a second side of the discontinuity (50;55).