Abstract: A servo control loop for tuning a center frequency of a tuning device to a desired frequency. More specifically, the dynamic range and response time of the servo loop are improved by closing the loop when the sign of the dither signal is such that the center frequency of filter would move towards the desired frequency when the loop is closed and by shifting the phase of the residual dither so that it adds at least partially in phase with the dither signal. The two components thus added are used to supply the control signal for the tuning device.

Abstract: A polling procedure providing the capabilities to assign and dynamically modify a user's communication parameters (i.e., response allocation and polling rate) based on the user's bandwidth requirements. In addition, the polling procedure instructs the users to delay their responses as a function of round-trip propagation delay and remaining response allocation for previously polled users to ensure that poll responses from separate users do not overlap.

Abstract: This invention discloses a method and apparatus for providing high speed optical tuning. With this invention, light is spatially routed through a tree of optical switches interconnected by waveguides to a selected fixed tuned optical filter in an array of such filters. Each of the optical switches can be controlled by a binary signal thereby permitting digitally controlled optical filtering.