Carl Zeiss Jena Gmbh

Karl-Heinz Bechstein

Beate Moeller

Andreas Wolfram

Klaus Dieter Salewski

Werner Fuchs

Klaus-Dieter Salewski

The present invention is directed to a heterodyne interferometer arrangement with tunable laser light sources for absolute distance measurement. The phase angle changes which occur in the synthetic interference signals when varying the laser frequencies are recorded and evaluated. The arrangement also enables error-free distance measurement in the event of a change in the mathematical sign of the phase changes due to frequency jitter.

Heterodyne interferometer arrangement with tunable lasers, a heterodyne

An interferometer for absolute distance measurement with two lasers, one of which is tunable with respect to frequency. A device for collinear superposition of the laser beams is arranged downstream of the lasers. Further, interferometer units are provided whose optical path lengths differ from one another. An individual acousto-optical modulator (AOM) is arranged downstream of the device for superposing the beams. Light-conducting elements for guiding the beams are arranged between the AOM, between the AOM and at least one first beam splitter arranged downstream of the AOM, and between the light outputs of the first beam splitter and the light inputs of one or more interferometer units arranged downstream and/or within these interferometer units.

Interferometer for absolute distance measurement

The invention is directed to a reference interferometer with variable wavelength, with an interferometer splitter, a reference beam path, and a folded measurement beam path passing between two plane mirrors. At least one spacer element 10 is provided for realizing a fixed position of the plane mirrors relative to one another. The two plane mirrors are arranged in a plurality of planes in a defined manner in relation to one another such that a light beam coming from the interferometer splitter and coupled into the space between the plane mirrors at an entrance point at a slight angle is reflected repeatedly at the plane mirrors, and the reflection points lie along a parabola on the surfaces of the plane mirrors. A retroreflector is arranged downstream of the first plane mirror in such a way that the light beam striking it can be returned to the entrance point or in the vicinity thereof along the same path or almost the same path.

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Jena, Germany

Karl-Heinz Bechstein