Optical interferometer using a high-birefringence optical fiber

The paper presents a prototype of a new displacement measuring system based on an optical interferometer using a polarization-maintaining optical fiber. The proposed configuration makes it possible to separate the laser head and the detectors from the actual interferometer (i.e., the measuring head). In this way, the interferometric head can be miniaturized and used to gauge targets which are difficult to access. The resolution provided by the electronic fringe counter is equal to λ/8 (~80 nm), and the overall accuracy is 1 μm over a measuring range of 20 mm.