Polarization interferometric architectures, preferably plane mirror types, having first and second measurement legs are provided with retardation elements, preferably, at least one set of split waveplates, comprised of two segments, tilted slightly (e.g., 2 mrad) in opposite directions with respect to each other to reduce the effects of undesirable ghost beams that otherwise would travel along the same path as the principal beams to produce significant cyclic errors. With the use of the split wa...

Bidirectional isolating devices including non-reciprocal rotators (i.e. Faraday rotators) and wavelength selective reciprocal polarization rotators are disclosed. Each wavelength selective rotator behaves like a half-wave retarder in a first frequency range and behaves like a full-wave retarder in a second frequency range, according to a substantially periodic transfer function. The rotation has a predetermined number of birefringent elements (e.g. waveplates), the thickness and the orientation ...

Optical components are louvered with a light absorptive material that absorbs stray light rays. The louvers are constructed, for example, using a "black" thin film coating between sheets of glass. The louvered components are placed in an optical path at one or more orientations. In one embodiment, a vertically oriented louvered component and a horizontally oriented louvered component are individually located in a light path to reduce and/or eliminate stray light having either horizontal and/or v...

A compensated higher order waveplate is constructed of substrates. In one embodiment, a first substrate is a n.lambda. waveplate and the second substrate is a (n+.DELTA.).lambda. waveplate. The substrates are oriented so that their principle axes of retardation are orthogonal. n.lambda. is a base retardation of a waveplate and .DELTA..lambda. is an incremental retardation. The incremental retardation produces a desired amount of retardation of a lightwave passing through the compensated higher o...