Abstract: An acoustic-optical device for optical filtering includes two successive acoustic-optical interaction segments separated by an intermediate polarizer and each modifying the polarization of light guided by it. The modification depends on the frequencies of the interacting optical and acoustic waves. The acoustic waves are supplied symmetrically to the two interaction segments from a common electro-optical transducer. The transmission spectrum of the optical filter is subject to apodization by coupling between an auxiliary acoustic waveguide including the transducer and a main acoustic waveguide including the optical waveguide. Applications of the device include fiber optic telecommunication systems.

Abstract: In a method for fixing a polarization-preserving optical fiber the fiber is illuminated transversely and orientation of the polarization-preserving plane of the fiber is monitored by direct visual examination of internal components of the fiber rendered visible by such illumination. The illumination is effected through the wall of a transparent ferrule holding the fiber. The method has applications in fiber optical telecommunications systems.