The instrumentation principles and designing of two kinds of white light scanning interferometer systems are studied. One

based on the two-beam Mirau phase-shifting interferometer and the PZT used as a phase shifter

is developed to measure the micro-profile with nanometer accuracy. The other

employing Michelson interferometer for light path compensation

with the polarization states adjusted and controlled by rotating a Glan prism

and by varying reference arm to compensate the difference of light path induced by polarization coupling point

is developed to measure the position of polarization coupling pointing optical fiber. The results are that the spatial resolution of autoecious Polarization coupling measuring apparatus is 50mm

the measure range is 1km

and the detection sensitivity is better than -80 dB.