Abstract: A ball lens connector part having low total reflections as well as a method of manufacturing such a ball lens connector part are described. The total reflections can be limited to less than -60 dB by means of the present ball lens connector part. The ball lens connector part comprises a fiber with an inclined fiber end in a tubular housing which housing further comprises a ball lens. If the ball lens comprises a flat surface, the total reflections can be lower than -80 dB. By subjecting the end of the housing to a machining treatment, the center line of the said end is moved in such a manner that it coincides with the optical axis of the emanating light beam.

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: A method of manufacturing lens elements, in which a glass preform heated to the softening temperature and an annular metal holder (3) enclosing the glass preform are arranged between the heated moulding dies (7,9) of a mould and are moulded in a pressing step into a lens element comprising a glass lens (21) and a ring (3) enclosing the glass lens and acting as a fitting. During moulding, the ring 3 forms together with the two dies (7,9) a quasi closed moulding cavity having an annular gap (15). During moulding, the ring (3) is expanded radially and a quantity of glass is pressed.

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 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.