Hybrid distributed optical fiber sensors for temperature, strain and vibration measurements

We describe hybrid distributed optical fiber sensor schemes for temperature, strain and vibration measurements. In particular, we first introduce the use of cyclic Simplex coding in hybrid Raman/BOTDA distributed sensors for fast long-distance strain and simultaneous temperature measurements over the same SMF, using a single narrowband source. The same advanced coding technique is also proposed to demonstrate a hybrid distributed acoustic and temperature sensor (DATS) based on Raman and coherent Rayleigh scattering processes in a standard SMF, using a single commercial off-the-shelf DFB laser and a common receiver block.