Polytec OFV-3001 - Page 86

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2)9  The optical configuration of the sensor head OFV-512 is shown schematically
in figure C.3.
In contrast to the OFV-511, the beam is coupled out of the reference arm as
well as the object arm here. As the resulting signal only depends on the path
difference, this allows optical generation of a true difference signal. With the
OFV-512 the prism in the reference arm is replaced by another beam splitter
BS4 which has the same characteristics as the beam splitter BS2. The signal
measured here is thus the relative velocity or displacement between the two
objects.
Figure C.3: Optical configuration of the interferometer in the sensor head OFV-512
BS 1 Object 1
BS 4
Bragg C ell
BS 3
BS 2Laser
Detector
Coupler
Fiber H ead
or
M ini S ensor
Object 2
R eference B eam
Object Beam
Fiber Head
or
M ini S ensor
Coupler
Fiber
Fiber
λ/4
λ/4