Microstructured optical fiber sensor

A microstructured optical fiber sensor for sensing changes in a physical characteristic up to a predetermined temperature is disclosed. The sensor comprises a microstructured optical fiber and a fiber Bragg grating formed in the microstructured optical fiber by generating a periodic modulation in the refractive index along a core region of the suspended core, the fiber Bragg grating configured to produce a band reflection spectra comprising a fundamental mode and a plurality of higher order modes whose respective wavelengths vary in accordance with changes in the physical characteristic at the core region of the microstructured optical fiber, wherein the microstructured optical fiber is configured to increase the confinement loss of the plurality of higher order modes of the band reflection spectra relative to the fundamental mode.