Abstract: In the optical connection of telecommuniation glass fibres to semiconductors a curable composition is used which comprises a polyester urethane acrylate or a polyether urethane acrylate. The composition furthermore comprises a heat- or light-activatable initiator.The refractive index of the cured connecting material is adjusted by the addition of both a reactive diluent which increases the refractive index and a reactive diluent which decreases the refractive index. Said reactive diluents furthermore serve to establish the desired mechanical properties of the connecting material prior to and after curing.The curable composition is provided on the glass fibres and/or on the semiconductor laser, after which they are contacted with each other and are optically aligned. The composition is then cured by raising the temperature or by exposure to light.

Abstract: An optical system which provides a collimated light beam, having a tubular holder, a semiconductor laser and a system of lenses incorporated in the holder, in which the semiconductor laser is positioned against an abutment in the axial direction of the holder and a resilient element is placed between the system of lenses and the abutment, while on the side of the system of lenses remote from the resilient element a locking element is present which, after axial adjustment in the holder, is fixed in such a location that the system of lenses, after moving in the axial direction against the pressure of the resilient element, is in the position in which its focus coincides with the laser element in the semiconductor laser.

Abstract: A semiconductor laser device includes a support having a substantially annular assembly block of a metal having a good thermal conductivity, which assembly block includes positioning means on its outer circumference for accurately locating the optical axis of said laser element and a sector-shaped supporting part which extends towards the center line of the block and which has a connection and mounting face for a laser element extending through the center line and accurately located with respect to the positioning means. A base includes mutually-insulated electrical conductors and a photodiode which is secured on the side of the assembly block remote from the supporting part, and a cap having a light-transmitting window is secured to the assembly block so as to form a hermetic envelope.