Reconfigurable photonic integrated circuits based on liquid-crystal-cladded slab waveguides

We present fully-reconfigurable photonic integrated circuits (PICs) based on liquid-crystal-cladded slab waveguides. Our design utilizes a single-mode slab waveguide with a thin nematic liquid crystal (LC) cladding layer. We achieve local effective index modulation by controlling the LC's director's direction through electrodes integrated beneath the slab. As a proof of concept, we demonstrate a straight waveguide at 1550nm with voltage-controlled activation. The reconfiguration time and the excess loss due to LC were measured as 0.1 ms and 7.3 dB/cm, respectively. The low-temperature fabrication process enables cost-effective PICs on CMOS chips for 3D sensing, telecommunications, and data processing applications.