To reduce power consumption and cross-talk when transmitting broadband optical signals without prior conversion into electrical signals, in a thermo-optical switch two waveguides (WL1 and WL2) extending closely adjacent over their interactive length (L) are at least partially covered across their width by at least one pair of lamellar electrode arms of the heating electrode (E) connected by way of a common cross-member (G). The shape of the electrode arms is geometrically similar to the shape of the wave guides thereunder (WL1 and WL2) and at least one electrode arm of an electrode arm pair is electrically driven.
