Patent ID: 6429963
Filing Date: 2002-08-06
Classification: G02B,H01S

Abstract:
An method of making a fiber optic filter having a predetermined peak attenuation wavelength &lgr;0 comprisingmaking an optical filter fiber having a central core, a ring core having an inner radius rR concentric with said central core, an inner cladding region of refractive index ni between said central and ring cores, and a cladding layer of refractive index nc surrounding said ring core, wherein the maximum refractive index n1 of said central core and the maximum refractive index n2 of said ring core are greater than nc and ni, wherein the maximum refractive index n2 of said ring core is greater than the maximum refractive index n1 of said central core the propagation constants of one core mode and one ring mode being different at wavelengths except for at least one wavelength &lgr;0, whereby a narrow band of wavelengths including &lgr;0 is coupled between said central core and the ring core, and subjecting at least a portion of said optical filter fiber to a sufficient curvature to obtain a predetermined amount of attenuation at wavelength &lgr;0.