Patent ID: 6754425
Filing Date: 2004-06-22
Classification: C03B,G02B

Abstract:
A manufacturing method of a dispersion flattened fiber with high negative dispersion ranging from about âˆ’20 ps/nm/km to about âˆ’60 ps/nm/km, comprising the steps of:(a) preparing a silica tube; (b) cleaning the silica tube; (c) forming a cladding on an inner peripheral surface of the silica tube; (d) forming a first ring-type core on an inner peripheral surface of the cladding; (e) forming a first low refractive region on an inner peripheral surface of the first ring-type core, wherein the refractive index of the first low refractive region is lower than that of the cladding; (f) forming a second ring-type core on an inner peripheral surface of the first low refractive region; (g) forming a second low refractive region on an inner peripheral surface of the second ring-type core, wherein the refractive index of the second low refractive region is lower than that of the cladding; (h) forming a central core on an inner peripheral surface of the second low refractive region; (i) heating the silica tube, thereby forming a preform of the dispersion flattened fiber; and (j) extracting the dispersion flattened fiber from the perform.