Method and arrangement for controlling a light switch for optical signals

In a control arrangement for the control of a plurality of light switches each constructed as a directional coupler in integrated technology, of the type in which optical signals are guided through a pair of light waveguides on a substrate, in which two light waveguides are arranged on the substrate and each include an input, an output and a section parallel and at least closely adjacent a like section of the other waveguide along a switching path, in which the light is selectively switchable for direct through connection or cross-connection between the inputs and outputs, in which each light switch comprises at least one electrically conductive and controllable electrode for controlling through and cross-connections, the improvement therein comprising:

• a semiconductor substrate carrying a digital/analog converter whose analog output is stabilized with respect to DC supply voltage fluctuations,
• said digital/analog converter including an output connected to said at least one electrode,
• said digital/analog converter including an input for receiving digital signals;
• a byte generator connected to said input of said digital/analog converter and operable to provide digital words thereto, each of said digital words corresponding to the individual analog voltage requirement of an individually determined one of said light switches for controlling said determined light switch by said corresponding digital word generated by said light generator,
• said byte generator comprising first and second memories, said first memory storing words corresponding to through connection of said light waveguide, and said second memory storing words corresponding to cross-connection of said light waveguides,
• said byte generator also comprising a third memory storing information regarding whether said first or second memory is to supply a word to said digital/analog converter;
• and
• transfer switch means connected between said first and second memories and said digital/analog converter and connected to and operated by said third memory.