One year later Cao et al proposed a thermal tuning filter based on a graphene-polymer-silica hybrid WG223 as shown in Figure 6b Its working scheme is to thermally manipulate the polarization and mode

In a subsequent study, Cao and colleagues proposed a thermal tuning filter that utilized a graphene-polymer-silica hybrid waveguide (WG). The device's operational principle relied on the efficient thermo-optic manipulation of its polarization and mode filtering properties, facilitated by the contrasting thermo-optic coefficients of the polymer and silica materials. To enhance the tuning efficiency, a low refractive index layer was introduced into the polymer-silica hybrid core. The filter was capable of realizing both single-mode and multimode filtering patterns, highlighting its versatility and potential for various applications. Figure 6b illustrates the structure and design of the thermal tuning filter