Abstract: An apparatus is disclosed comprising a polarization mode selection switch for preselected wavelengths using a waveguide having a first array of PIN type diodes mounted in a plane extending substantially perpendicular to a longitudinal waveguide axis. The diodes are disposed at one-quarter wavelength intervals along a first series of parallel lines which are separated at about one-half wavelength intervals. A second PIN diode array is also mounted within the waveguide in a second plane extending substantially perpendicular to the waveguide axis with diodes disposed at one-quarter wavelength intervals along a second series of parallel lines that are also spaced about one-half wavelength apart. The second plane is substantially parallel and adjacent to the first plane with the second lines being oriented substantially perpendicular to the first lines.

Abstract: An apparatus for detecting deflection of the spin axis of a gimbal supported spinning mass relative to the gimbal axis comprises four equally spaced linear arrays of detector elements mounted around the gimbal axis and extending parallel to that axis. Four light sources are provided, each one in alignment with a respective one of the arrays, and a reflective surface is provided on the spinning mass for reflecting light onto the respective detector arrays. Deflection of the spin axis will be registered by displacement of a reflected light spot in one or more of the arrays.