Thermally stable optical fibre Bragg grating wavelength reference
in: Optics Communications (2011)
The inherent temperature dependence of optical fibre Bragg gratings is causedmainly by the positive thermo-optic effect of thefibre corematerial, and it results in an increase of Bragg wavelengthwith temperature. Specialmounting techniques may be designed in order to compensate this thermo-optic effect by counter-acting effects: decreasing mechanical strain, as well as a decreasing effective refractive index for the guided light wave by evanescent field interaction with a liquid of negative thermo-optic effect. Because of the non-linear interaction characteristics, exact temperature compensation is obtained for a certain temperature, which depends on the design parameters. Such stabilised fibre Bragg gratings find application as wavelength references in Bragg grating sensor networks.