Partial power recovery of bend-induced loss using a hybrid index-guiding photonic crystal fiber

In this work, we present a solid-core endlessly single mode (ESM) PCF infiltrated with PDMS elastomer conserving index-guiding mechanism. PDMS (poly-dimethylsiloxane) is a polymeric widely used material in optoelectronics (particularly in opto/microfluidics) with refractive index lower than silica (around 1.41). Normally, the temperature dependence of the refractive index is described by the thermo-optic coefficient dn/dT (-4.5/°C for PDMS-Sylgard 184), which quantifies the shift of the refractive index arising from an infinitesimal change of the temperature. Here, we demonstrate the combination of a conventional PCF with the aforomentioned polymeric material and we show how the thermo-optic effect can act in a way to partially reconstruct the fundamental guiding mode highly attenuated by bending losses.