Patent ID: 6427041
Filing Date: 2002-07-30
Classification: G02B

Abstract:
An article comprising a tilted refractive index grating having a tilt angle &thgr; and extending longitudinally over at least a portion of a single mode optical waveguide having a core and a cladding that surrounds the core, the core having a dopant distribution selected to provide a radial refractive index profile n(r) and a radial photosensitivity profile p(r), where n and p are the refractive index and the photosensitivity, respectively, and r is the radial coordinate of the optical waveguide, where p(r) varies as a function of r in the core, with p(r) having at least two levels of photosensitivity in the core, said tilted refractive index grating having a coupling constant &kgr;(&thgr;) that determines coupling between a forward propagating core mode of said wavelenght &lgr; and a reflected core mode of wavelength &lgr;;CHARACTERIZED IN THAT a) p(r) is selected such that p(r) is independent of n(r) and has at least one tuning region of differing photosensitivity within the core of the single mode optical waveguide; and b) n(r) and p(r) are selected such that &kgr;(&thgr;) is less than âˆ’30 dB over a range of &thgr; that is greater than 0.1Â°, whereby manufacture of a tilted refractive index grating having substantially no reflected core mode is facilitated.