Abstract: A spherical lens (5) is fixed to the front end of a tubular housing (1) and an end part of a lightconducting fibre (9) is fixed with its first end face (11) in the focal plane of the lens. The line through the center (13) of the lens (5) and the middle of the first end face (11) is the optical axis (17). The housing (1) with the lens (5) is placed against a seat (25), which is formed as a cavity with a rotationally symmetrical surface, on whose axis of rotation (27) a light detector (31) is mounted. The detector is designed to determine deviations between the direction of a light beam coming from the lens and the direction of the axis of rotation. Near the second end face (45) of the fibre (9) light is injected into the fibre, and the rear end of the housing is displaced in two directions (x, y) perpendicular to the optical axis, until the light beam emerging from the lens ( 5) coincides with the axis of rotation (27). The lens (5) with the seating (25) thereby functions as a ball hinge.

Abstract: The electro-optical switch in accordance with the invention comprises one or more nematic crystals (7) for the deflection of polarized light. In order to enable deflection of a light beam in two perpendicular directions by means of two electrically controllable crystals, the beam (4) of unpolarized light is converted into a beam (6) of polarized light in a low-loss manner.

Abstract: The invention relates to an optical demultiplexer whose "color band" is adjustable, so that the demultiplexer can always be adapted to future standards. The adjustment is performed either by tilting the optical grating with respect to the light beam incident thereon or by deflecting the light by means of a liquid crystal arranged in the light path.

Abstract: A planar reflecting grating is described which is suitable for use in an optical multiplexer or demultiplexer. This grating comprises a periodic structure of elongated areas which are formed at constant distances from each other in a thin light-conducting layer deposited on a substrate. In their longitudinal directions, the areas have periodic ridges, corresponding ridges extending parallel to each other.

Abstract: A device for driving a laser (2) includes a quiescent-current means (3) which supplies, under control of a negative feedback current (I.sub.D) from a photodetector (9), a quiescent current (I.sub.B) to the laser in order to stabilize the laser light output at a level corresponding to a logic one value of a digital input signal (D). A modulation device (10), which comprises a converter, is responsive to the digital input signal to supply a first drive current (i.sub.M1) to modulate the laser. The modulation device supplies a second drive current (i.sub.M2), complementary to the first drive current, to a compensation device (20) which, for a logic zero signal, applies a compensation current (I.sub.C) to the quiescent current means thereby to reduce the light level.

Abstract: In optical multiplexers and demultiplexers which utilize interference filters and optical gratings losses and noise are reduced by converting the unpolarized light into linearly polarized light. This improves the efficiency of the filters and gratings and suppresses noise which is caused by fluctuations in the degree of polarization of unpolarized light because filters and gratings have different characteristics for the different polarization directions.

Abstract: A geodesic optical component consists of a light-guiding layer on a substrate. The substrate has a surface corrugation which determines the optical function of the component. Since the surface corrugation has a wavelike character, it is possible to obtain the desired optical function while limiting the maximum depth or height of the corrugation, so that the component can be accurately produced using inexpensive pressing or etching techniques.

Abstract: The invention relates to a method of manufacturing an optical grating from a body having a surface which is provided with equidistant grooves. In order to obtain cheap and deformation-resistant gratings, according to the invention a surface of a substrate is provided with a number of layers of substantially equal thicknesses. The etching rates of the layers (in a given etchant) increase substantially proportionally to the number of the layer. A cross-sectional surface of the layers is then exposed to the etchant to form the surface with the grooves.

Abstract: A method of manufacturing a geodetic-optical component is described in which non-spherical rotationally symmetrical recesses are formed in a surface of a substrate, and the surface with the recesses are covered with a planar waveguide. This technique forms the recesses in a laminated substrate having a number of layers of varying etching rates, and then etching these layers to form cup-shaped recesses.

Abstract: An optical branch coupler comprising a semi-transparent mirror which is tiltable about an axis which is situated substantially in the plane of the mirror and substantially parallel to the plane determined by the directions of the transmitted and the reflected light beams. A wall toward which the reflected beam is directed is adjustable about an axis which is at right angles to the plane of the light beams.

Abstract: A method of manufacturing a fiber-optical coupling element by fusion of two monomode fibers. The fiber cores are made of a core glass, the American softening temperature of which is at least 80.degree. C. higher than that of the cladding glass. The fibers are heated to a temperature between 520.degree. and 560.degree. C. By the method, fibers can be fused to form a coupling element without undesirable deformation of the fiber cores.

Abstract: An optical multiplexer whereby the light from a plurality of optical fibers can be combined in an optical transmission fiber via an input lens, a prism and an output lens. The lenses are preferably ball-lenses. The multiplexer does not comprise any color-selective elements.

Abstract: A detachable connector for coupling a pair of optical fibers includes two connector elements detachably connected to a connector holder. Each connector element includes a cylindrical housing, a spherical lens, a disc-shaped fiber holder, means for adjusting the axial displacement of the fiber holder in the housing, and means for adjusting the displacement of the holder perpendicular to the axis. The spherical lens is mounted in a conical bore in the housing, adjacent the fiber holder.

Abstract: The invention relates to a method of and a device for providing an outer surface of an envelope which is concentric to a light-conductive core, around a monomode optical fiber. According to the invention, the eccentricity of the fiber and the envelope may be for example, 0.1 .mu.m for a core diameter of 3 .mu.m. This accuracy is acieved by splitting a light beam, emerging from the end of a fiber which is clamped in an envelope, into two subbeams by means of rotating optical means, each of the beams producing a circular image. By a suitable choice and adjustment of the optical means, the two light beams will form oppositely moving images when the fiber end is displaced with respect to the axis of rotation and observation. When the images are concentric, the fiber end is situated on the axis of rotation. Machining of the envelope by the use of a tool which rotates around the axis of rotation results in an envelope which is concentric to the light-conductive core of the fiber.

Abstract: A detachable connector, for coupling the ends of optical fibers, comprising two connector portions, each connector portion having fixing means, for detachably connecting the connector portions to each other, and at least one rotationally symmetrical housing having a bore which is coaxial to a central axis. The housing has a reference face at one end and adjusting means secured in the bore at an opposite end. The adjusting means enables an optical axis, of an end of an optical fiber to be secured in a tube, and to be adjusted parallel to the central axis of the housing. When the two interconnected connector portions contact each other by way of the reference faces, the optical axes of the fibers in each connector portion are parallel to one another.