US Patent 10976493 Controllable diamond waveguide tuner

An example device in accordance with an aspect of the present disclosure includes a diamond waveguide disposed on a substrate. The substrate includes a dielectric material. A tuner is to extend from the substrate, and is disposed at least in part over the waveguide. The tuner includes a tuner electrode to control a variable distance between the tuner and the waveguide to vary an effective refractive index of the waveguide.