Optical fiber interferometer and piezoelectric modulator

Abstract

The invention is related to technical physics, in particular to devices for investigating the internal structure of objects and can be used in medicine for diagnostics of human organs and systems, in particular for optical coherence tomography and in technical diagnostics, for example technological process control. The invention relates to the creation of an optical-fiber interferometer, which, being used in a device for optical coherence tomography, allows one to investigate media with short time of changing of optical characteristics or its position relative to the optical probe, for example biotissues in vivo. The invention also relates to the creation of a piezoelectric modulator, suitable for use in the interferometer and for providing the necessary scanning depth in the mentioned media. In the described optical fiber interferometer the piezoelectric modulator, constructed as a fiber optic piezoelectric controllable delay line, performs a function of the fiber part of the interferometer arm which allows one to change practically inertialess the optical path in the interferometer arm and consequently an optical path difference at least to several tens of the working wavelenghts. The described piezoelectric modulator is constructed as a fiber optic piezoelectric controllable delay line and contains a piezoelectric plate with electrodes and an optical fiber situated on its opposite sides. It is expedient to make the plate in a disk form and to put the fiber as a spiral which allows one to change the optical path in a wide range while keeping the modulator inertialess and compact.