Patent ID: 6183918
Filing Date: 2001-02-06
Classification: G02B

Abstract:
An alignment system for maintaining correct alignment between a photosensitive optical fiber and an ultraviolet beam illuminating the photosensitive optical fiber through a phase mask, while the ultraviolet beam is scanned along the photosensitive optical fiber in a first direction to create an optical filter in the photosensitive optical fiber, comprising:a positional transducer causing an oscillation in relative position between said photosensitive optical fiber and said ultraviolet beam in a second direction differing from said first direction;an optical transducer coupled to an end of said photosensitive optical fiber, receiving from said photosensitive optical fiber light produced by fluorescence in said photosensitive optical fiber when said photosensitive optical fiber is illuminated by said ultraviolet beam, and converting said light to a first signal, said first signal having an oscillating component due to said oscillation in relative position; anda control circuit coupled to said optical transducer, comparing phases of said first signal and said oscillation in relative position, and adjusting the relative position of said photosensitive optical fiber and said ultraviolet beam in said second direction according to a phase relationship between said first signal and said oscillation in relative position.