Fiber-Optic Nerve Systems for materials that can feel pain

Optical fibers can act as a sensor for strain or temperature through the properties, such as scattering. By applying ways to analyze distribution of the property along the fiber, "fiber optic nerve systems" are realized to sense damages induced in materials and structures, in which the fiber is embedded. We have proposed and developed a technique named "Brillouin Optical Correlation Domain Analysis; BOCDA". It is based on control of the correlation between the pump and probe continuous lightwaves, which excite the Stimulated Brillouin Scattering (SBS). A Single Side Band (SSB) Modulator can act as an ideal frequency shifter, and generate a probe ligtwave with a downshifted frequency. Strain distribution measurement with a long range has been demonstrated. By the correlation domain technique, we have also developed several "fiber optic nerve systems," including the multiplexed Bragg grating sensors with the same Bragg wavelength.