CALIBRATING VOLTAGE CONTROLLABLE OPTICAL ELEMENT IN COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To provide a method and an apparatus for setting an operating (control) voltage of a voltage controllable optical element having a periodic voltage/optical parameter characteristic. SOLUTION: The apparatus includes: a means operable to set the voltage (V) applied to the component to a predetermined initial value, that is, an up/down counter and a D/A converter; a means for measuring the optical parameter (P); a means for sequentially progressively increasing and decreasing the voltage (incrementing/decrementing the counter) with respect to the predetermined value; and a means for determining the respective voltage values (V0and V∞) which produce the maximum and minimum values of the optical parameter. The means operable to set the voltage sets the voltage (V) to an intermediate value ((V0+V∞)/2). Further, the apparatus comprises a means for determining the sense of the slope of that portion of the periodic characteristic lying between the maximum and minimum values for use by a control loop during subsequent operation of the optical element. COPYRIGHT: (C)2008,JPO&INPIT