Abstract: Embodiments of the present invention are directed to rotational actuators or rotators that rotate an object in a worm-like manner. One rotator includes piezoelectric members that are controlled to expand and contract in a predetermined sequence to rotate a ring. The rotator includes first and second coupling members which are adjustable in length to move between a coupled position being coupled with the ring and a decoupled position being decoupled from the ring. A top advancing member is connected between the top coupling end of the first coupling member and the top coupling end of the second coupling member. A bottom advancing member is connected between the bottom coupling end of the first coupling member and the bottom coupling end of the second coupling member. The top and bottom advancing members are adjustable in length to produce relative movements between the top coupling ends and between the bottom coupling ends, respectively.

Abstract: Apparatus and method for monitoring an optical signal using a locally generated clock signal instead of a clock signal recovered from the optical signal. Numerous eye diagrams are generated based on a ratio between the known local clock and numerous estimates of the bit rate of the optical signal. The best eye diagram is selected, and the actual bit rate of the optical signal is then determined. Given the actual bit rate, time-varying performance of the optical signal may be monitored.