A phase modulator may include a middle layer having a first refractive index, a first surrounding layer of material in contact with the middle layer and having a second refractive index, a second surrounding layer of material in contact with the middle layer and may having a third refractive index, a first electrode in electrical contact with the first surrounding layer, and a second electrode may be in electrical contact with the second surrounding layer. When no voltage is applied across the first electrode and the second electrode, the first refractive index may be greater than the second refractive index and the third refractive index. When a voltage is applied across the first electrode and the second electrode, the first refractive index may be less than the second refractive index within a portion of the phase modulator substantially within an electric field induced by such voltage.