Patent ID: 7911622

Claim:
An optical sensor comprising: at least one optical coupler; and an optical waveguide in optical communication with the at least one optical coupler, the optical waveguide configured to receive a first optical signal from the at least one optical coupler, wherein the first optical signal has a group velocity and a phase velocity while propagating through at least a portion of the optical waveguide, the group velocity less than the phase velocity, wherein an interference between the first optical signal and a second optical signal is affected by perturbations to at least a portion of the optical sensor, wherein the perturbations comprise a change of strain and a change of temperature of the at least a portion of the optical waveguide, the optical sensor has a strain sensitivity to the change of strain and a temperature sensitivity to the change of temperature, and the at least a portion of the optical waveguide has a group index such that a ratio of the strain sensitivity to the temperature sensitivity is at or near a minimum.