Abstract: An optical cable is provided which is especially adapted for use in reading optical information from an optical information carrier. The cable includes a light conductor adapted for transmitting light from the information carrier to a light-sensitive receiver. The light conductor includes a major portion of an easily bendable material such as a plastic. It also includes an end portion extending beyond the major portion of the light conductor which faces away from the light-sensitive receiver. The end portion constitutes a separate light conductor, the reception angle of which is less than the corresponding angle of the major portion. The end portion is preferably fabricated of glass or quartz. The arrangement may be such that there is a plurality of further conductors positioned about the first said conductor and also manufactured of an easily bendable material.

Abstract: A fibre-optic cable responsive to microbending and forming part of a device for measuring pressure in accordance with the principle of creating a periodic mechanical disturbance in the fibre. The cable comprises a fibre (F) having a core (C) and a core-sheathing (M). An elongated element in the form of a twisted filament (T1, T2) or a twisted band (B) extends along the fibre, and a primary shield (H) encases the fibre and the twisted element such that the twisted element contacts the sheathing at periodically spaced separate regions.

Abstract: The invention relates to a fibre-optic Mach-Zehnder Interferometer for measuring such as change in length. Two light conducting fibres (1,2) are connected to a coherent light source (5). A measurement converter (6), actuated by a measurement quantity (P) changes the length of the optical path and thereby the phase angle for the light wave in one fibre (2). The phase angles for the light waves in the fibres (1, 2) are compared and a corresponding output signal (I) is fed back to compensate for the phase angle change in the measurement converter (6). To make the comparison result (I) independent of the light intensities in the light conducting fibres (1,2) these are connected to an opto-electronic directional coupler (7). This is selected such that the output signal (I) varies as the phase displacement .phi., according to the relationship: I=2.times.A.times.B.times.sin .phi., where A and B are the amplitudes of the light waves in the fibres (1,2).

Abstract: A joint for optical fibres includes a guide sleeve (1) for concentric guidance of the fibre ends, and two ends sleeves (4,5) which are fastened around the guide sleeve and are provided with threads for threadable engagement with end fittings on the respective fibre end. One of the end sleeves (4) is united with an exterior sleeve (8) in which the other end sleeve (5) can be screwed. A locking sleeve (10) has the same external thread as the other end sleeve (5) and may be screwed into the external sleeve (8) so that it engages against the end sleeve (5) to function as a lock nut for the latter.