Abstract: In a system for tracking a target which is illuminated by a laser beam, for example, apparatus is required to determine how far the target is off-axis. The apparatus includes an objective lens (3) which concentrates light coming from the target onto a reception surface (8). A group (12) of bundles (13,14,15,16) of optical wave guides is disposed between the reception surface (8) and a single photoelectric receiver (21). Each bundle conveys light from a respective portion of the reception surface. The bundles (13,14,15,16) of wave guides are of different lengths. Thus, the optical signals transmitted by the various bundles are received successively by the single receiver. This avoids problems of matching the sensitivity of different receivers responsive to different portions of the reception surface.

Abstract: The invention relates to a laser generator. That generator comprises optical resonant cavity of the folded type, limited by two plane mirrors arranged in a same plane, side by side and a corner cube reflector for sending back the radiation coming from one of the said mirrors towards the other mirror. Application to telemeters and to illuminators.