Patent Number: 6,253,008

Title: Optical filter and method of making the same

Abstract: The present invention relates to an optical filter having a long-period grating which couples, in signal light propagating through a core region, core mode light having a predetermined wavelength to cladding mode light, thereby attenuating the core mode light; and a method of making the same. In particular, in the filter area provided with the long-period grating, the intervals of individual parts exhibiting its average refractive index is constant along the advancing direction of the signal light, whereas values of maximum points and minimum points of a refractive index modulation function defining the refractive index vary along the advancing direction of the signal light.

Inventors: Harumoto; Michiko (Kanagawa, JP), Shigehara; Masakazu (Kanagawa, JP)

Assignee: Sumitomo Electric Industries, Ltd.

International Classification: G02B 5/18 (20060101); G02B 6/10 (20060101); G02B 6/00 (20060101); G02B 6/34 (20060101); G02B 006/34 ()

Expiration Date: 06/26/2018