Abstract: Two (2) optical fibers each having a core, a cladding enveloping the core and a buffer enveloping the cladding are spliced. First and second positions are adjacent the first fiber and third and fourth positions are adjacent the second fiber. The second and third positions are respectively closer to the splice than the first and fourth positions. Light emitters are at the first and fourth positions and light detectors are at the other positions. Light from each emitter is selectively passed to individual ones of the detectors. Members (e.g. solid gels) adjacent the emitters direct light into the associated fibers. Other members (e.g. solid gels) respectively between the first and second positions and between the third and fourth positions inhibit the light passage in the fiber claddings and buffers so that only the light in the fiber cores passes to the detectors. The gels and the fibers are clamped to provide matching dimples for trapping in the gels the light in the claddings and buffers.

Abstract: In a method and a device for assortment of objects a broadbanded light is emitted from a light source, which light is reflected via a rotary mirror against the objects falling freely immediately after they have left a conveyor belt. The reflected light is led via the other part of the same surface of the rotary mirror to an optical unit and is reflected against a double detector dividing the light flow into two wide ranges about 1 .mu.m. The detector signals are compared to one another and after processing the resulting signal is caused to actuate means separating the objects mechanically.

Abstract: In an optical head, a laser beam emitted from a semiconductor laser is collimatted by a convex lens and is reflected by a polarizing surface of a prism. The reflected laser beam passing through a quarter wave plate is converged by an objective lens onto an optical disk. The laser beam reflected from an optical disk is returned to the prism through the objective lens and quarter wave plate. The returned laser beam passes through the polarizing surface and is reflected from two segment surfaces of a prism coupled to the prism. The laser beam is reflected and separated into two beams by the segment surfaces. The separated beams passing through the polarizing surface are converged by the convex lens onto a photodetecting unit located close to the semiconductor laser.