Flexible waveguide integrated thermo-optic switch based on TiO2 platform

Mechanically flexible photonic devices are critical components of novel bio-integrated optoelectronic and high-end wearable systems, in which thermo-optic switches (TOSs) as optical signal control devices are crucial. In this paper, flexible titanium oxide (TiO 2 ) TOSs based on a Mach–Zehnder interferometer (MZI) structure were demonstrated around 1310 nm for, it is believed, the first time. The insertion loss of flexible passive TiO 2 2 × 2 multi-mode interferometers (MMIs) is −3.1 dB per MMI. The demonstrated flexible TOS achieves power consumption ( P π ) of 0.83 mW, compared with its rigid counterpart, for which P π is decreased by a factor of 18. The proposed device could withstand 100 consecutive bending operations without noticeable degradation in TOS performance, indicating excellent mechanical stability. These results provide a new perspective for designing and fabricating flexible TOSs for flexible optoelectronic systems in future emerging applications.