All-optical Data-input Device Based on Fiber-optic Interferometric Strain Gauges.

Abstract

An experimental fiber-optic data-input device called data-cube is described. Three double-polarization Michelson-interferometers on separate panels are mounted in a cubic housing. They are used as optical strain gauges for measuring the bending-induced surface strain of elastic bars. Two interferometers serve as force- or displacement sensors for manual input commands, the third one measures the orientation of the cube with respect to the gravity vector by means of an accelerometer arrangement. The measured characteristics of strain via bending, as induced by the external force, is compared with the theoretical relationship. First results of a polarimetric method for initialization of the incremental readout are presented. It is based on measuring the phase difference between the two orthogonally polarized interference signals.