Optical waveguide gratings having cladding for reduced short wavelength cladding mode loss

摘要

In accordance with the invention, an optical waveguide (10) comprising a longitudinally extending core (12) housing an optical grating (16) and a cladding layer (14) peripherally surrounding the core (12), is provided with an outer surface (18) of the cladding layer having one or more perturbations (20). Each perturbation (20) has a height with respect to the core (12) that varies by at least 0.1 times a Bragg wavelength of the grating (16) over the surface of the perturbation (20) and covers an extent of the outer surface (18) whose linear dimensions are less than 1 cm. The perturbations (20) suppress cladding mode spectra and reduce short wavelength cladding mode loss.