Abstract: A light amplifier includes a source of multiple light beams, each modulated with the same information, and a plurality of light amplifying optical fibers, each amplifying one of the light beams. The amplified light from each amplifying fiber is converted to electric form, and the electrical signals are summed to add the information and average the noise. In one embodiment, the bundle of fibers is twisted as it is wound about a cylinder, to average the compressive and tension forces on the fibers of the bundle. In another embodiment, a common cladding surrounds a bundle of fibers.

Abstract: A notch filter includes a directional coupler (16) with an input port (17a), coupled output port (17b), coupled 0.degree. (17d) and direct 90.degree. (17c) ports. A cylindrical dielectric resonator (40) is supported by a spacer (58) above a ground plane (14) and dielectric substrate (12). A first microstrip transmission line includes a strip conductor (22) coupled at one end to the coupled 0.degree. port, and extending parallel to a tangent to the edge of the resonator at a central plane (44), terminating in an open-circuit (226). A second transmission line includes a strip conductor (24) coupled to the direct 90.degree. port (17c) and extending parallel to the first transmission line, on the other side of the resonator. The first and second transmission lines each have an electrical length .lambda./4 between the central plane (44) and their open-circuit terminations, to reflect a high current to the plane.

Abstract: A modulator or demodulator has a transparent nonlinear dielectric material (crystal), and an optical fiber for coupling light thereinto. RF is coupled into the crystal by a dielectric waveguide which is matched to the crystal. The nonlinear crystal causes the light and RF to interact, to cause products which can be detected at the dielectric waveguide. When used as a modulator or demodulator, the modulated light may be coupled out by a second optical fiber, and or the modulated RF may be coupled out by a second dielectric waveguide. The dielectric waveguide may be transitioned to conventional hollow conductive waveguide.