Patent ID: 6400865
Filing Date: 2002-06-04
Classification: G02B

Abstract:
An article comprising an optical waveguide mode converter for converting light of wavelength &lgr; in a few-moded waveguide from a given guided mode to another guided mode, the mode converter comprising a tilted refractive index grating in the waveguide, the grating having a tilt angle &thgr;, the few-moded waveguide having a core and a cladding surrounding the core, with the mode converter being associated a multiplicity of coupling strengths, whereina) the few-moded waveguide has a dopant distribution selected to provide the waveguide with a refractive index profile n(r) and a photosensitivity profile p(r), wherein n(r) and p(r) are functions of the radial coordinate of the waveguide; b) p(r) has at least two different levels of photosensitivity in the core; and c) n(r), p(r) and &thgr; are selected such that more than one of said coupling strengths are simultaneously nulled, and such that at least one of said coupling strengths is substantially maximized.