An optical modulator includes a confinement region of semiconductor material defining at least a portion of a light path through the optical modulator. The optical modulator also includes electrical contacts for connection with a voltage source for injecting carriers into the confinement region. The injected carriers impede light propagating through the confinement region, to thereby modulate light intensity. Contact regions in electrical contact with the confinement region remove injected carriers from the confinement region. Methods of modulating light and of making the optical modulator are also disclosed.