Non-volatile optical waveguide switch based on electro-thermic chalcogenide phase change material

A non-volatile 2×2 optical waveguide switch structure is proposed based on silica wafer integrated with chalcogenide Ge₂Sb₂Se₄Te₁ (GSST) quaternary phase change film and silicon strip waveguide. By applying external electrical pulses on indium tin oxide (ITO) electrodes which are deposited on GSST film, the phase change film can be heated and non-volatile switched back and forth between the two phase states for turning on or off the optical transmission paths. Such an electrically controlled waveguide switch structure is established and simulated by using COMSOL Multiphysics software. The response time of the optical switch is determined by the phase transition time of the amorphous and crystal states of GSST. The results show that it requires about 0.5μs from crystal state to amorphous state with a pulse voltage of 16V, and the energy consumption is 11.36nJ. The amorphous state will remain non-volatile until the next specific pulse arrives. The response time is about 1.3μs from amorphous state to crystal state with a pulse voltage of 5V, and the energy consumption is 2.41nJ. The heat dissipation times are both under 3.0μs. The working wavelength is set at C-band of optical communication with central wavelength of 1550 nm. This type of non-volatile optical waveguide switch presents fast responses, low energy consumption and smart characteristics, which provides an optional possible implementation approach for the construction of large-scale and high-capacity on-chip optical switching networks.