Tuning of the Brillouin scattering properties in microstructured optical fibers by liquid infiltration

We demonstrate the possibility to modify the Brillouin scattering properties of a microstructured pure-silica core optical fiber, by infiltrating a liquid inside its holes. In particular, we show that the dependence of the Brillouin frequency shift (BFS) on the temperature can be reduced by infiltration, owing to the large negative thermo-optic coefficient of the liquid. Infiltrating a chloroform-acetonitrile mixture with a refractive index of 1.365 inside the holes of a suspended-core fiber with a core diameter of 3 & mu;m, the BFS temperature sensing coefficient is reduced by & AP; 21%, while the strain sensitivity remains almost unaltered. Besides tuning the temperature sensing coefficient, the proposed platform could find other applications in Brillouin sensing, such as distributed electrical and magnetic measurements, or enhanced Brillouin gain in fibers infiltrated with high nonlinear optical media.

Automated summary

We demonstrate the possibility of modifying the Brillouin scattering properties of a microstructured pure-silica core optical fiber by infiltrating a liquid into its holes. The dependence of the Brillouin frequency shift (BFS) on temperature can be reduced by infiltration due to the liquid's large negative thermo-optic coefficient. By infiltrating a chloroform-acetonitrile mixture into the holes of a suspended-core fiber, the BFS temperature sensing coefficient is reduced by approximately 21%, while the strain sensitivity remains almost unchanged. This platform could have applications in Brillouin sensing for distributed electrical and magnetic measurements or enhanced Brillouin gain in fibers infiltrated with high nonlinear optical media.