Abstract: A system for modifying an input optical signal by reducing its bandwidth and modifying its central wavelength has an optical circulator with at least three ports and at least two optical filters coupled to consecutive ports of the circulator. The first filter produces a predetermined reflected band off the input optical signal. The second filter produces a predetermined transmission band as a part of the reflected band. Either or both of the optical filters are tunable to shape and trim the input signal in a predetermined manner. A multi-channel and cascade configurations may be formed. The system may serve e.g. as a tunable filter or as an add/drop module in WDM communication networks.

Abstract: A low profile optical switching device has a housing with a width and length considerably greater than its height, a motor having an upright shaft extending less than the height of the housing, a circular faceplate surrounding an upper end portion of the shaft and having a diameter considerably larger than the length of the shaft, and a plurality of first optical fibers each having a fixed fiber end portion held by the faceplate. The fixed fiber end portions, usually constituted by lenses, are arranged so as to define a substantially cylindrical imaginary surface co-axial with and communicating with the faceplate. These fixed fiber end portions can receive light from a further optical fiber having a movable end portion carried by an arm extending radially from the motor shaft and which moves around a circular path adjacent the fixed fiber end portions, the light being transmitted via a prism mounted on the arm adjacent the movable fiber end portion.