Temperature insensitive long-period fiber grating devices
AssigneeLucent Technologies Inc.
InventorsDavid John DiGiovanni, Justin Boyd Judkins, Janet Renee Pedrazzani, Ashish Madhukar Vengsarkar, Kenneth Lee Walker
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Abstract
Applicants have determined that the temperature sensitivity of long-period grating devices is due to differential variation with temperature of the refractive indices of the core and cladding. They have further determined that the cladding profile and fiber composition can be redesigned to substantially reduce this differential variation, thereby reducing the temperature sensitivity of long-period gratings of less than 4 nm per 100.degree. C. and preferably less than 2 nm per 100.degree. C. This design permits the use of long-period grating devices without temperature control or compensation.
Claims11
A long-period grating device having enhanced stability to variations in temperature comprising:
- an optical fiber including a core having a refractive index and a core guided mode with effective index n.sub.eff, core, with a rate of change with respect to temperature dn.sub.eff, core /dT;
- a cladding surrounding said core having a cladding mode with effective index n.sub.eff, cladding, less than n.sub.eff, core and an average rate of change with respect to temperature dn.sub.eff, cladding /dT;
- wherein said core has a plurality of perturbations in its refractive index spaced apart by a periodic distance .LAMBDA. to form a long-period grating with a center wavelength .lambda.p;
- and wherein dn.sub.eff, cladding /dT is sufficiently close to dn.sub.eff, core /dT that the rate of change of .lambda.p with respect to temperature is less than 4 nm/100.degree. C.
Dependencies are inferred from the claim text.