Patent ID: 6362916
Filing Date: 2002-03-26
Classification: G02B

Abstract:
An all fiber optical filter formed from stretching an optical fiber and comprising a fiber optic core, an inner cladding formed concentrically about the fiber optic core, and an outer cladding formed concentrically about the inner cladding, wherein an outer index of refraction of the outer cladding is less than a core index of refraction of the fiber optic core and further wherein the outer index of refraction is greater than an inner index of refraction of the inner cladding, wherein the optical fiber is stretched to form:a. a filter length separating non-stretched input and output lengths; b. a reduced diameter core along the filter length; and c. a reduced thickness inner cladding along the filter length; and further wherein the optical fiber is stretched until evanescent coupling is achieved between the fiber optic core and the outer cladding along the filter length.