Thermo-optic control of a topological boundary mode

We investigate thermo-optic-induced delocalization of a topological mode in a 1D Su-Schreiffer-Heeger system with a domain wall possessing non-zero Zak phase of varying magnitudes. Thermal perturbations are applied to the domain wall, inducing a change in its local refractive index via the thermo-optic effect and causing a perturbation in the system's chiral symmetry. The ultra-silicon-rich-nitride (USRN) material on which the device is implemented has a large thermo-optic coefficient of 2.48X10^-4/°C, similar in magnitude to the refractive index variation caused by the third-order nonlinear Kerr effect (dn/dW = 1.2X10^-4/W). We experimentally characterize the transmission properties of the topological waveguide and observe thermo-optic-induced changes owing to the perturbation of the topological mode. We further experimentally observe modulation of the idler generated using nonlinear parametric wavelength conversion induced by the thermo-optic effect.