Abstract: The invention discloses a light modulator comprising a semiconductor substrate, a curved thin-film semiconductor optical waveguide having a predetermined curvature and, semiconductor electrode layers formed contiguous to the waveguide, whereby when a potential is applied across the electrode layers, the carrier density in the regions adjacent the waveguide may be varied and consequently the radiation loss in the curved waveguide may be varied accordingly to modulate light radiating through the waveguide in response to the electric potential applied across the electrode layers.