Abstract: A coupling device for coupling an end of a light-conducting fiber to an optical transmitter device and an optical receiver device. The receiver device comprises a light-collecting element arranged opposite an end face of the fiber end. The receiver is provided with an opening. The transmitter device comprises a transmitter element arranged opposite the opening behind the light-collecting element. A transmitter lens is provided for focussing light emitted by the transmitter device onto the end surface of the fiber end. In order to obtain a construction which can be coupled in a simple manner, a transparent body optically coupled to the fiber end, the light-collecting element and the transmitter element is arranged between the fiber end face and the light-collecting element body has reflecting side faces. As a result, substantially all the light emanating from the fiber end strikes the light-collecting element.

Abstract: A semiconductor laser of the double heterojunction (DH) type having a current-confining buried blocking layer. According to the invention, a high-resistance region having a disturbed crystal structure is present outside and on either side of the strip-shaped active region and extends at least throughout the thickness of the blocking layer. As a result, the lateral leakage currents and the parasitic capacitances are reduced so that the laser can be used at frequencies considerably higher than 1 GHz. The high-resistance region is preferably obtained by protron bombardment. The invention is particularly advantageous in DCPBH lasers for optical communication.

Abstract: A connector, for coupling pairs of (monomode) optical fibers, comprising a central connection portion, with a V-groove, and two holders. A cylindrical envelope of an optical fiber is arranged in each holder to be resilient in the longitudinal direction. A pin 4 is secured parallel to each envelope. The envelope is retained in the V-groove by a hold-down spring. When the envelope and the pin are inserted into the central connection portion, the envelope is clamped by a clamping spring which is actuated by the pin after the envelope has reached its ultimate position, e.g. against an abutment pin.

Abstract: Apparatus for modulating the output signal of a converter for converting electric signals into other signals, for example optical signals. An analog signal is applied to a subtraction device (6) the output signal of which controls a limiter (7). The binary output signal thereof controls the semiconductor laser diode (1) which is coupled to a photo-sensitive detector (3) for producing a feedback signal. After being amplified in a broad-band amplifier (9) and integrated in an integrator (13), this feedback signal is applied to the subtraction device (6), so that the feedback signal is subtracted from the analog signal. Variations in the optical output signal due to a non-linear conversion characteristic of the laser diode (1) and due to an optical retroaction of the fibre (2) on the laser diode, as well as output noise and signal-dependent amplitude variations, are reduced by the negative feedback.

Abstract: A semiconductor switching device for guiding and amplifying electromagnetic radiation is disclosed. An electrode pattern which defines a number of strip-shaped guiding members is provided on a layer structure analogous to that of a semiconductor laser. According to the invention the radiation guiding members have tapering juxtaposed ends in a transition area. Adjacent radiation guiding members in the transition area are situated within each other's amplification profile. The radiation guiding members are preferably separated from each other by insulation areas which do not extend to the common active layer. The invention may be used, for example, in switching radiation signals between two or more radiation paths in optical communication.

Abstract: Control circuit for controlling a laser drive current. In known control circuits certain levels of the optical output signal are kept constant. This renders it difficult to satisfy certain requirements during the life of the laser as regards the linearity of the modulation of the optical output signal. In the described control circuit the intermodulation of two signals present in the modulation signal with substantially constant amplitudes is measured, an error signal which controls a component of the drive current being derived therefrom.

Abstract: In optical communication systems as well as in video disc playback equipment, it is necessary to position a light source such as a semiconductor laser at an exact distance from a lens of the optical system. In accordance with the invention this is done by mounting the laser in a tubular cover which is in a telescopic, press fit engagement with a holder provided with the lens. The desired exact distance between the laser and the lens is adjusted by relative compression between the cover and the holder. Because the engaging walls of the cover and holder are covered with a layer of indium, the walls will slide smoothly over each other during adjustment of the desired distance.