Parameters that Affect the Backscattered Signal Power due to Stimulated Brillouin Scattering in Optical Fibres

摘要

The main objective of this paper is to analyze by simulation the parameters affecting backscattered signal power in optical fibres. Parameters affecting the backscattered power were investigated and the possibility of using these parameters to model a distributed fibre optic sensor was done. In this research work investigations were carried out using VPI software for simulations. The investigation show that when the pump and stokes (probe) wave counter propagate in the fibre there is transfer of energy between the pump and stokes wave resulting in the pump and stokes waves being depleted and amplified respectively as they travel along the fibre. Thus the Brillouin gain peaks at Brillouin frequency. Further investigations show that the backscattered power was low for input power below 5 d Bm but increased rapidly above it and saturated above input power of 10 dBm for different fibre lengths. The effect of Polarization Mode Dispersion (PMD) on Stimulated Brillouin scattering (SBS) was found to decrease the signal power over time. Further results showed that power reduces with increase in temperature and the frequency shift (Brillouin shift) is directly proportional to temperature and this was used to map out the temperature change along the fibre.