Physics, technology, and status of the emerging field of all-fiber guided wave components, which are based on three fundamental technologies namely, fused fiber couplers, side-polished fiber silica blocks, and optical fiber Bragg gratings are reviewed. Applications of these components as in-line fiber devices are also discussed along with an extensive bibliography.
As the component technology for optical telecommunication systems advances, more and more mechanisms that influence the performance are discovered. After the problems of modal and chromatic dispersion were solved, polarization effects became to play an important role. Due to the polarization transmission properties of optical devices the magnitude and phase of the lightwave's electric-field components are changed depending on the state of polarization of the lightwave. Fiber-optic polarimetric sensors make constructive use of these polarization effects to measure physical quantities like temperature, strain, pressure and electric currents. In other cases, like long-haul telecommunication systems, polarization effects will result in shorter transmission distances. Both, the positive and negative effects of polarization, require measurement techniques to analyze the component's polarization properties. In this paper, a fiber-optic polarization synthesizer which is able to generate any desired state of polarization is described. Using a novel self-calibration procedure, this setup is completely self-supporting. The construction of the polarization synthesizer will be explained in detail and it will be shown, how this setup allows a simple measurement of the polarization properties of optical devices.
Theory and experiments using inverse Fourier spectroscopy are presented of cross-coupled modes induced by laterally loaded pressure along a some length of birefringent single-mode fiber. The results are successfully applicable to the determination not only of the location but also of the extent of the applied pressure.
An optical neural network system with learning capabilities and a 2-D architecture is proposed. The 2-D architecture is implemented by a multiple imaging system of a Selfoc microlens array, which enables us to develop a compact optical neural network system. Synaptic weights of neurons are memorized in the Pockels readout optical modulator, and the system obtains the learning capabilities. Experimental verification of multiple imaging and learning is presented. In the experiments, the neural network system stores the three patterns by an orthogonal learning method. The performance of the optical neural network system is estimated in terms of a point spread function of the Selfoc microlens.
Mercury cadmium telluride (MCT) infrared detectors are the typical ones among those with high sensitivity near BLIP characteristics in the wavelength region of 8-12μm atmospheric window. These semiconductor materials have been the most important compound semiconductors since the first synthesis about 40 years before and are still studied by many researchers in this time. In this review, overview of MCT is summarized in view of practical application on the base of historic background. At first, the features of the MCT materials are briefly commented, and crystal growth techniques and state of the art of device technology are described. Finally future trend for this field is briefly commented.
Electordeposited composition modulated alloy (CMA) coatings have been and can be prepared from a large number of alloys systems. They make it possible not only to make device for e.g. X-ray mirrors but also to utilize the unique magnetical properties of CMA artificial superlattices.