Using electrochromic materials for optical switching

Optical communication relies on precise phase control to ensure minimal signal loss in waveguides. The current state-of-the-art technique uses the thermo-optic effect, where heating changes the refractive index, providing precise control on the path of light. Here, I propose using electrochromic lithium manganese oxide (LiMn₂O₄, LMO) as a waveguide cladding. The evanescent wave extends into the cladding, so changing the cladding’s refractive index influences light propagation and phase. Previous work has shown a change in refractive index in the visible region. Building on that, we measured IR reflectance spectra showing continuous visible-to-IR transitions, 100% reflectance, and resonance shifts with lithiation. Calculations show that a 38µm waveguide can induce a π phase shift at 1550 nm. We also explore different delithiation methods to change optical properties without degrading the optical structure itself.