Nanometer scale measurement of wear rate and vibrations by fiber-optic white light interferometry

A white light interferometric method for nanometer scale measurement of wear events by fiber-optic sensing configuration is presented. The proposed contactless technique is capable of measuring the wear rate and vibrations of the pin in a standard pin-on-disc tribometer remotely and simultaneously. All data are obtained by an interferometric reading of the sensing fibers displacement using a passive demodulation technique employing a 3 × 3 fiber-optic coupler and mechanical scanner. We obtained a pin position resolution better than 100 nm in the range of 400 μm as well as minimal detectable amplitude of the pin vibration of about 50pm/Hz.