A control system for the optical-fiber piezoelectric modulator of the optical path

The operating principle of an optical-fiber piezoe lectric modulator of the optical path in all-opti-cal-fiber interferometers is described. The control system of the optical-fiber piezoelectric modulator is composed of a controller based on a field programmable gate array, a digital-to-analog converter, an analog low-pass filter, and a power amplifier. A 4.4-m/s speed of chan ge in the optical length of the fiber has been attained with an error of 0.1% at a modulation length of the optical path of >1 mm.