Patent ID: 6314222
Filing Date: 2001-11-06
Classification: G02B,H01S

Abstract:
A long-period grating filter device having long-period fiber gratings for permitting the use of said long-period fiber grating without temperature control, comprising:an optical fiber including a core having a plurality of refractive index modulations spaced apart by a predetermined distance for transmission light of a given wavelength;a cladding surrounding said core defining a boundary between said core and said cladding;a recoating covering a portion of said cladding surrounding said refractive index modulations defining a cladding-recoating boundary;a coating covering a portion of said cladding not surrounding said refractive index modulations;wherein a response wavelength shift of said refractive index modulations exhibit a negative variation with temperature increase in relation to an amount of a dopant incorporated into said core; andwherein a response wavelength shift by an ambient refractive index of said cladding exhibits a positive variation with temperature increase, said wavelength variations by said recoating and said long-period fiber grating, which are opposite in sign, canceling each other.