Abstract: Optical elements utilize multimode interference in a piece of an optical fiber of multimode type having a core in the shape of a ring or a tubular structure. Such a fiber can be compared to a planar waveguide, the core of which has been bent about a longitudinal axis located at some distance from the core. Such an optical fiber can be optically excited having an excitation centre in a point on or at the annular core by coupling from a single-mode fiber. Then different optical propagation modes are excited having approximately regular relations between their phase velocities so that, for example, for a suitable length of the fiber piece a light intensity is obtained in the other end of the fiber piece which is an approximate reflected image of the light intensity supplied at the input end of the fiber piece.

Abstract: For improving mechanical characteristics of an aged optical glass fiber, the segment is retained between clamps, e.g. in a conventional splicing machine. Then the segment is heated to a high temperature in the vicinity of the softening temperature or melt temperature of the glass material of the fiber by means of an infrared light beam from a carbon dioxide laser or by an electric arc generated between the welding electrodes. In particular, the tensile strength is increased considerably by this procedure, what allows that the heated segment can be handled and exposed to the operative steps required for splicing the fiber to another optical fiber. Then also old fibers arranged in the ground can be repaired and spliced, and it is not necessary to replace whole lengths of old fibers.

Abstract: The present invention relates to a lensless spectrum analyzer, preferably of integrated optical type, with a radiation source (1) connected to a waveguide (2) which is connected to an electro-optical deflector (3), exploiting Pockel's effect. The radiation from the deflector (3) is guided by the waveguide (2) on to a detection matrix (4). The electro-optical deflector (3) then consists of an electrode matrix (5) with the electrodes (6-11) arranged in or in the vicinity of an electro-optically active material (21). The electrodes (6-11) which are of different widths and are disposed at different distances from each other are arranged along a line (18) which is largely disposed at right angle to the incident radiation. By this means, the deflector acquires lens properties and can perform the desired Fourier transformation of the electric signal connected to the deflector (3).

Abstract: The invention relates to an optical measuring device for measuring physical magnitudes such as position, speed, acceleration, force, pressure, elongation, temperature, etc., comprising at least one optical fiber for conducting light between an electronic unit and a transducer forming an optical modulator which is directly or indirectly influenced by the quantity being measured and, in dependence thereon, modulates the light emitted to the transducer. The transducer contains at least one optical filter having spectrally varying absorbing and/or transmitting and/or reflecting characteristics within the spectra of the emitted light. The light filter generates one or more stabilizing signals for the fiber optic and optoelectronics, and possibly one or more measurement signals within one or more wavelength ranges.