Abstract: A laser interferometer system for measuring roll angle around the direction of linear displacement comprises a light source of a frequency stabilized input beam (15) with two linear orthogonally polarized components which may or may not be of the same frequency, a polarizing beam splitting prism, two quarter-wave retardation plates, a corner cube retroreflector, a prism assembly, attached to the mechanical apparatus whose roll angle of travel is to be measured, a wedge mirror assembly, a polarizer, a photoelectric detector, and a phase meter; the light source emits a frequency-stable incident beam and generates a stable electric reference signal; under the actions of the polarizing beam splitting prism, quarter-wave plate and corner cube retroreflector, the incident beam travels twice through and then reflected twice by the wedge mirror assembly, and finally exits from the polarizing beam splitting prism.

Abstract: A laser interferometer system for measuring roll angle around the direction of linear displacement comprises a light source of a frequency stabilized input beam (15) with two linear orthogonally polarized components which may or may not be of the same frequency, a polarizing beam splitting prism, two quarter-wave retardation plates, a corner cube retroreflector, a prism assembly, attached to the mechanical apparatus whose roll angle of travel is to be measured, a wedge mirror assembly, a polarizer, a photoelectric detector, and a phase meter; the light source emits a frequency-stable incident beam and generates a stable electric reference signal; under the actions of the polarizing beam splitting prism, quarter-wave plate and corner cube retroreflector, the incident beam travels twice through and then reflected twice by the wedge mirror assembly, and finally exits from the polarizing beam splitting prism.

Abstract: A heterodyne interferometer arrangement comprises a two-frequency light source, an optical reference branch for producing a reference signal, an optical measuring branch, which includes an interferometer unit causing a phase rotation of the light beams in response to a length to be measured, as well as a measuring transducer arranged at the output of the interferometer unit, and a phase comparator arranged subsequent to the reference transducer and the measuring transducer. In order to minimize linearity errors, the measuring transducer comprises first and second optoelectric measuring transducer units, which respond to light components orthogonal to each other and which are followed by two phase comparators whose output signals represent phase differences between the first or the second measuring signal on the one hand and the reference signal on the other, and a mean value generation circuit whose output signal represents the mean value of the first and second phase differences.