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Kilometer length, low loss enhanced back scattering fiber for distributed sensing

We demonstrate a 1km long optical fiber with continuous grating enhanced back scattering and attenuation close to standard single mode fiber. Scattering was observed to be more than 10dB above the Rayleigh back scattering of the optical fiber over a 10nm bandwidth between 1542 and 1552nm. The fiber attenuation was estimated to be 0.4dB/km. Our result was enabled through the fabrication of a standard single mode fiber with a UV transparent coating and reel to reel continuous UV grating inscription over more than 1km. We anticipate that enhanced scattering fiber will have impact in many sensor systems that rely on optical back scatter, including distributed acoustic sensing, security applications and structural health monitoring.