Abstract: The invention relates to a method, a device and a method for installing a cable in a tubular cable duct. In the method, the foremost end (3) of the cable (1) in the duct (10) and subsequent portions of the cable are first accelerated in a short time with continuous supply of further portions of cable from a torsion-free store. Then, from the instant a certain speed v is reached, the cable is maintained at a tension such that, at said speed and tension, centrifugal forces in bends and inwardly pulling components of tensioning forces in the cable compensate for one another at the position of said bends, the further portions of the cable being supplied at a supply speed such that the part of the cable already fed into the duct can continue to slide on the basis of its mass moment of inertia.

Abstract: An improved method for installing a cable (4) in a tubular cable conduit (6) with the aid of the drag forces of a flowing medium by applying additional tensile forces by a partially leaky pulling plug (10) coupled to the foremost end (8) of the cable and a partially leaky pulling plug for carrying out the improved method. The plug is provided with a suitably dimensioned flow opening (12) for allowing the flow through of the flowing medium in a manner not reducing the drag forces considerably, however with a certain pressure difference (Px--Px') across the plug (10). This pressure difference imparts thrust to the plug. The thrust of the plug exerts additional tensile forces on the foremost end (8) of the cable. Preferably the plug has a circumferential suction seal with the inside wall (11) of the conduit (6), and the flow opening is dimensioned such that during installation the flow velocity in the flow opening is essentially equal to that of sound in the flowing medium.

Abstract: Mode converter for converting a fraction of one guided mode of an optical signal in an incoming optical waveguide section (A) into another guided mode in an outgoing wave-guiding section (C) by means of a periodic coupling between both guided modes in an intermediate optical waveguide section (B). The intermediate section (B) has a periodic geometrical structure as a result of an N-fold periodic sequence of two light-guiding subsections (P, Q) within a period length (L.sub.P +L.sub.Q). The sequence can be obtained by arranging for the waveguide profiles of the subsections to differ from one another, preferably as a result of differences in width. The sequence can also be obtained by offset joining of the two subsections with the same waveguide profiles.

Abstract: In a digital optical switch which is based on the mode-selectivity principle, made up of a passive section (A) containing a first optical wave guide (1) and a second optical wave guide (2) and a switching section (B) containing a third optical wave guide (3) and a fourth optical wave guide (4), both the required asymmetry and the bringing of the optical wave guides within or outside each other's interaction region are achieved with the aid of curves (K.sub.1, K.sub.2) in respective walls of the optical wave guides. In the switching section (B) said asymmetry is reversible. Use is made of the effect that a curved wall results, in general, in a reduction of the propagation constant in the optical wave guide. Suitable curves are of circular-arc shape and sinusoidal. The switching section (B) may furthermore incorporate a short intermediate section (s-u) in which the optical wave guides (12, 13) run straight at a small mutual angle (.PHI.

Abstract: A compact deflecting device for the conveyance of letters or the like in one of a plurality of selectable directions, is formed by a large number of deflecting components (1-1, --, 1-4) placed at a mutually equal distance along an endless conveyor (15) driven in a main conveyance direction (A). Every component combines a deflecting and conveying function with relatively small space requirement. For this purpose, it comprises not only a downstream-pointing deflecting tongue (4) but also a guide roller (6) which are both mounted on a swivel arm construction (9, 10), which can be swivelled by activating a rotary magnet (2) between two positions. Every component (1-1, --, 1-4) is positioned and dimensioned in a manner such that, when swievelling from one position to the other, the access to a conveyance direction deviating from the main direction is freed or essentially closed off and that, in both positions, the guide roller (6) continues to interact in a conveying manner with the conveyor (15).

Abstract: A buffer system for the temporary separate storage of flat articles such as letters for sorting, video coding or other postal processing, uses a buffer which acts as a mechanical RAM and contains a number of storage pockets for separate storage of articles. A conveyance system is provided by elastic clamping on an endless conveyor. The conveyance system is separately controllable in the storage pockets as a letter catchment, retainment and ejection device. Buffers are situated along a branching feed section. Letter logging signals are transmitted for every letter conveyed along the feed section and run in parallel with the branched feed section. These signals in all cases include a letter identification code assigned when the letter is fed into the system. At that stage an application control continuously makes a selection of letters which are eligible for discharge from the system. The system can readily be equipped either as a sorting system or as a video coding system.

Abstract: The invention relates to an integrated optical polarization splitter based on the mode filter principle, in which the asymmetry, necessary therefor, of the waveguides is obtained by using a polable glassy polymer as optical waveguide material, which material is polarization-sensitive in the poled state and is not, or virtually not polarization-sensitive in the unpoled state. A Y-shaped optical waveguide pattern 8 of polable glassy polymer comprises a continuous optical waveguide formed by the optical waveguide sections 8.1 (incoming) and 8.2 (outgoing) in which the polymer is in the unpoled state and an outgoing optical waveguide section 8.3 which connects to said optical waveguide at an acute angle and in a tapered fashion and in which the polymer is in the poled state. Since the poled material is also electro-optical, an electric field, for example generated between electrodes 2 and 10, can still correct any small deviations in the asymmetry.

Abstract: A light conducting layer is formed from a poleable or poled glassy polymer material, which has an e/o activity which is definitively destructable under ionizing radiation. A selective irradiation under a parallel beam will give sharp transitions from and e/o active area (or an area which can still be electro-optically activated) to an e/o inactive area. The buffer layers can also consist of such irradiated material. A suitable positioning of the electrodes between which, by means of a difference in voltage applied across the electrode connections, an electric field with a sufficient intensity and/or uniformity can be induced extending into the border area, on both sides of the transition boundaries, will make it possible to induce sharp refractive-index transitions. This is utilized to obtain sharp lateral definitions of waveguides induced by electric field poling in thin layers of glassy polymers.

Abstract: The flow of data cells through a transmission medium with a plurality of virtual, asynchronously time-divided transmission channels is protected against excessive crowding of data cells in any channel, or of any customer, by means of a counter for each channel and the recording of the time or arrival of data cells in each channel. The counter is advanced by a predetermined amount at the arrival of each data cell and in the same operation is decreased by a value which is a function of the length of time between the moment of arrival of that data cell and the moment of arrival of a preceding data cell with the same channel designation. The state of the counter is also compared with a threshold value which, if equalled or exceeded results in the data cell not being switched through a switch controlled by the comparison, while in other cases the data cell is let through to the downstream portion of the channel.