Control arrangement for optical mechanical switches

Abstract

An arrangement and a method for monitoring and controlling an optical mechanical switch, which may include one or more microelectromechanical switches. In communication using the arrangement or the method, independently of any customer signal, a modulated optical signal is generated at wavelengths, both modulation and optical, that are out-of-band with respect the wavelengths of any transmission signals that may appear. The modulated optical signal is directed toward the optical mechanical switch, and system control parameters are changed to maximize a detected signal after passage through the optical mechanical switch. Any remnants of the modulated optical signal may be removed before arriving at any customer-related terminal. Optical cross-connect switching circuits are exemplary circuits in which the invention may be applied. The modulated optical signal is inserted before or during the transmission of any transmission signal. If accomplished before the transmission of any customer signals, the relevant switch control parameter is dithered by a servo system to increase the amplitude of the detected signal. During the transmission of signals to a customer terminal, a less obtrusive change of a switch control parameter is employed. In either case, the detected signal is used in a servo system to reduce system loss. Since the monitoring and control signals are at known levels, the needed dynamic range for the detector is much reduced.