A Passive Way To Extend Dtss System Distance

Brillouin or Raman-based Distributed Temperature and Strain Sensor (DTSS) provide a chance to distributed measure the temperature and strain over tens of kilometer with higher resolution. Lots of efforts, for example, Raman amplifier, Signal processing methods et al, have been used to extend their sensing distance and increase their sensitivity and signal-noise ratio. A sensing fiber, which has a gradually increasing Brillouin gain-coefficient g(B)/A(eff) or Raman gain-coefficient g(R)/A(eff) along its length and which can keep the received Brillouin or Raman Stoke's power constant in a Brillouin or Raman DTSS, is proposed in this paper. This novel fiber and practical fiber link with such nonlinear coefficient profile can further double or triple extend the sensing distance of the distributed Brillouin or Raman Fiber-optic Sensor system.