Abstract: A sensor for detecting the level of accumulation of a material along an axis in a fluid environment, the sensor comprising (a) an optically transparent body having a third refractive index and an exposed surface defining a length extending at least partially in the direction of the axis; (b) at least one light delivery source for delivering light to the body such that the light is distributed along the length of the exposed surface; and at least one light receiver for receiving reflected light from the length of the exposed surface, wherein the amount of the reflected light depends on the level of the material accumulated along the length of the exposed surface.

Abstract: A sensor for detecting the level of accumulation of a material along an axis in a fluid environment, the sensor comprising (a) an optically transparent body having a third refractive index and an exposed surface defining a length extending at least partially in the direction of the axis; (b) at least one light delivery source for delivering light to the body such that the light is distributed along the length of the exposed surface; and at least one light receiver for receiving reflected light from the length of the exposed surface, wherein the amount of the reflected light depends on the level of the material accumulated along the length of the exposed surface

Abstract: A reconfigurable liquid crystal based optical add/drop multiplexer system and method are provided which incorporates switching, variable attenuation, and multiplexing/demultiplexing capabilities. In a preferred embodiment, an array of optical rails is provided such that the integration of multiplexing/demultiplexing, switching, and variable optical attenuation functionalities are achieved. The module is also able to perform add and drop functions independently. The system has no moving parts so that the module is durable and very reliable. The system may include a feedback system for performing channel equalization.