A very small high-reflectivity mirror surrounded by a low-reflectivity region is fabricated in a self-aligned manner directly on one of the output faces of a stripe-geometry solid-state laser. The phenomenon known as filamentation is thereby effectively controlled.

A method is disclosed for coating the surface of an optical structure, such as a diffraction grating, useful for the detection of a ligand, which method comprises forming on the surface of the optical structure a thin, uniform layer of a polymerizable material, particularly one which polymerizes on exposure to light or heat, and subsequently exposing said material to polymerizing conditions. A specific binding partner is subsequently absorbed on or bound to the cured polymer layer, either directly or indirectly. Complex formation between the specific binding partner and ligand present in the sample to be analyzed alters the optical properties of the device and the change forms the basis of an assay.

A plurality of optical transceivers are disposed on a given curved plane confronting the mirror surface of a cylindrical mirror with their optical axes pointing toward said mirror surface. Information transmission paths for optical signals are defined between the mirror surface and the curved surface. An optical signal emitted from one of said plurality of optical transceivers is reflected by the mirror surface, and incident upon the remaining transceivers serving now as receivers.

An adjustable connector assembly for a laser effect diode, a focussing lens and an optical fibre in an optical fibre transmission system comprising a tubular body generally symetrical about the axis. One end of the tubular body, namely the front end, is provided with an adjustable diode socket assembly means including a first adjustment means at the front end and a socket means for filtering the focussing lens. The other end of the tubular body is provided with a fibre assembly means including transverse second adjustment means so that the ends of the optical fibres may be adjustably positioned in the transverse or xy plane relative to the axial direction, the Z axis of the tubular body. Thus the luminous ray or beam diverted by the diode is adjustable by the first adjustment means at the front end which can vary the position of the diode to the focussing lens in the Z divertion, e.g., axial direction, the transverse or xy adjustment at the fibre optic ends being provided by the second adjustment means at the other end of the connector. The connector is characterized in that said first adjustment means (10) comprises a first socket (21) carrying said diode (D) and secured with tight friction in a second socket (22) insertable in a predetermined position in the body (1) and in which a third socket (23) carrying the lens (4) can slide with easy fit. The connector also comprises radial fingers (232) screwed in the third socket (23) for positioning the lens, said fingers being freely guided in the axia direction through slots (103) provided in the body (1) and displaceable or immobilizable in said axial direction by means of nuts (24) framing said fingers and screwed on the outer periphery of said body.

An optical fiber has an end face adjoining the flat side of a plano-convex microlens of spherical curvature made from thermoplastic material. The microlens, overlying at least the entire cross-sectional area of the fiber core at that end face, is produced by juxtaposing a substantially spherical microball with that end face, heating the microball--preferably by a pulsed laser beam--to a temperature at which it deforms and spreads over the fiber face, and letting it cool. Also disclosed is an optimum numerical relationship between the radius of curvature of the convex surface of the microlens and the distance of its apex from a virtual point source, such as a laser, illuminating that microlens with a divergent beam.