Capacitive sensing scheme for digital control state detection in optical switches

A microelectromechanical system (MEMS) apparatus, comprising

• a. an element configured to rotate between a first control state and a second control state;
• b. a vertical stop disposed proximate the element;
• c. one or more electrodes disposed proximate the element, wherein a capacitance between the element and the one or more electrodes has a first value when the element is in the first control state and the capacitance has a second value when the element is in the second control state;
• d. means, for measuring a value of the capacitance between the element and the at least one of the one or more electrodes;
• and
• e. means coupled to the capacitance sensing means for determining a control state of the element from the value of the capacitance.

An optical communications system, comprising:

• a) one or more input optical fibers;
• b) one or more output optical fibers;
• c) a microelectromechanical system (MEMS) optical switch including:
• ii) one or more MEMS mirrors configured to rotate between a first angular position and a second angular position;
• ii) b. a vertical stop disposed proximate one or more of the MEMS mirrors;
• iii) one or more electrodes disposed proximate each of the one or more mirrors, wherein a capacitance between the mirrors and the electrodes has a first value when the mirrors are in a first control state and the capacitance has a second value when the element is in a second control state;
• iv) means, for measuring a value the capacitance between at least one of the one or more mirrors and the at least one of the one or more electrodes;
• and
• v) means coupled to the capacitance sensing means for determining a control state of the element from the value of the capacitance.