Recoatable temperature-insensitive long-period gratings
AssigneeLucent Technologies Inc.
InventorsAnatoli A. Abramov, Arturo Hale, Ashish Madhukar Vengsarkar
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Abstract
Applicants have determined that the temperature sensitivity of long period grating devices is substantially affected by the provision of a polymeric coating over the conventional glass cladding and, in particular, that by providing a polymer overcoating with an appropriately selected index of refraction, one can minimize temperature sensitivity. In a preferred embodiment, the temperature sensitivity of a long period grating written in conventional dispersion-shifted fiber is reduced to 0.40 nm/100.degree. C.
Claims19
A long-period grating with a center wavelength .lambda..sub.p having enhanced stability to variations in temperature comprising:
- an optical fiber including a core having an effective mode index of refraction n.sub.core, a cladding surrounding said core having an effective mode index n.sub.cladding less than n.sub.core, said core having a grating region comprising a plurality of perturbations in its refractive index spaced apart by a periodic distance .LAMBDA. to form the long period grating with a center wavelength .lambda..sub.p ;
- wherein a polymeric overcoat layer is disposed around said cladding along said grating region, said polymeric overcoat layer having a refractive index n.sub.p and a first derivative with respect to temperature n.sub.p /dT, and said polymeric overcoat layer is substantially thinner than the diameter of said optical fiber;
- and wherein n.sub.p and dn.sub.p dT are chosen so that the rate of change of .lambda..sub.p with respect to temperature is less than 1 nm/100.degree. C.
A long-period grating with a center wavelength .lambda..sub.p having enhanced stability to variations in temperature comprising:
- an optical fiber including a core having an effective mode index of refraction n.sub.core, a cladding surrounding said core having an effective mode index n.sub.cladding less than n.sub.core, said core having a grating region comprising a plurality of perturbations in its refractive index space apart by a periodic distance .LAMBDA. to form the long period grating with a center wavelength .lambda..sub.p ;
- wherein a polymeric overcoat layer is disposed around said cladding along said grating region, the polymeric overcoat layer having a refractive index n.sub.p and a first derivative with respect to temperature dn.sub.p /dT, and said polymeric overcoat layer is substantially thinner than the diameter of said optical fiber;
- and wherein n.sub.p and dn.sub.p /dT are chosen so that the rate of change of .lambda..sub.p with respect to temperature is less than 1 nm/100.degree. C. without applying strain to the fiber.
A long-period grating with a center wavelength .lambda..sub.p having enhanced stability to variations in temperature comprising:
- an optical fiber including a core having an effective mode index of refraction n.sub.core, a cladding surrounding said core having an effective mode index n.sub.cladding less than n.sub.core, said core having a grating region comprising a plurality of perturbations in its refractive index spaced apart by a periodic distance .LAMBDA. to form the long period grating with a center wavelength .lambda..sub.p ;
- wherein an unpackaged polymeric overcoat layer is disposed around said cladding along said grating region, said unpackaged polymeric overcoat layer having a refractive index n.sub.p and a first derivative with respect to temperature dn.sub.p /dT, and said unpackaged polymeric overcoat layer is substantially thinner than the diameter of said optical fiber;
- and wherein n.sub.p and dn.sub.p dT are chosen so that the rate of change of .lambda..sub.p with respect to temperature is less than 1 nm/100.degree. C.
Dependencies are inferred from the claim text.