Integrated acoustooptic heterodyne interferometer

Abstract

Abstract A heterodyne interferometer has four fibre optic light guide sections (1, 2, 3, 4) applied to a lithium niobate crystal (CR) by titanium diffusion and interconnected by a polarization divider (T1). One of the light guide sections passes through an electro-acousto-optico converter (M1) in which monomode light (S) is supplied. Each light fraction of a polarization (TM, TE) is sent to a reference branch and a measurement branch from where the light, reflected and/or modulated by a 1/4 wavelength plate, is returned to the waveguide sections (2, 3). It then passes through the polarization divider (T1) and the fourth waveguide section (4) to a second polarization divider (PBS) and from there to photodetectors (D1, D2), where it is evaluated. Other embodiments are disclosed. The interferometer has a high light yield and a broad measurement range and is suitable for use in anemometers, devices for measuring speed and vibration, and displacement sensors.

Inventors

• 👤 Wolfgang Prof. Dr. Sohler

Bibliographic Details