CHIRPED DIFFRACTION GRATING

摘要

A waveguide comprises a chirped diffraction grating, in which the chirping of the grating is provided, at least in part, by means of a variation in the effective refractive index of the waveguide along at least part of the length of the grating. The variation in the effective refractive index may be provided by a variation in one or more lateral dimensions of the waveguide.