Patent ID: 6447959
Filing Date: 2002-09-10
Classification: G02B,G03F

Abstract:
An amplitude mask for writing long-period gratings in optical waveguides comprising:a base optic made of a material capable of transmitting actinic radiation for writing the long-period gratings in a photosensitive medium of the optical waveguides; a shadow-forming pattern along the base optic that provides for illuminating periodically distributed segments of the photosensitive medium with the actinic radiation transmitted through the base optic; first transmissive portions of the shadow-forming pattern that convey first portions of the actinic radiation to the periodically distributed segments of the photosensitive medium; second transmissive portions of the shadow-forming pattern that relatively divert second portions of the actinic radiation away from adjacent segments of the photosensitive medium; each of the first transmissive portions being arranged for illuminating a corresponding segment of the photosensitive medium; the first and second transmissive portions alternating in position along the base optic; and one of the first and second transmissive portions including an array of diffractors for, relatively diffracting the first and second portions of the actinic radiation.