Optically controllable all-fiber based radio-frequency phase-shifter

This work develops an optically controllable all-fiber, radio-frequency phase-shifter based on a side-polished fiber (SPF) overlaid with a photo responsive liquid crystals (LCs). The phase shift of the LC-overlaid SPF (LCSPF) is tuned by modulating the refractive index (RI) of LC, which is determined by the phase transition of the overlaying photo responsive LC that is formed by the trans-cis photoisomerization of doped azobenzene molecules under light illumination. All-optically controllable devices have various advantages over all-electrically controllable devices, including compactness and simplicity of design.