Few mode fibers based quasi-single mode Raman distributed temperature sensor

We demonstrate a distributed temperature sensor based on quasi-single mode (QSM) Raman scattering in few mode fibers (FMFs). The FMF allows much larger input pump power before the initiate of stimulated Raman scattering compared with the standard single mode fiber (SSMF) and mitigates the detrimental differential mode group delay (DMGD) existing in the conventional multimode fiber (MMF) based Raman distributed temperature sensor (RDTS). Distributed temperature sensing is realized using conventional RDTS hardware over 20km FMFs within 90s, with a spatial resolution of 3m. The temperature resolution is 2.3°C @10km and 6.7°C @20km, respectively.