Apparatus for controlling the output power of a laser diode the beam of which is directed in a selected direction toward a target so as to enable a missile or the like to be directed along the beam toward the target. The apparatus includes a circuit which supplies a variable amount of power to the diode, and a circuit which is responsive to the radiation emitted by the diode, and the latter circuit generates a signal which is proportional to the magnitude of the emitted radiation. A control circuit is provided which is initiated into operation at the time of firing of the missile and generates a signal which represents the desired increase in magnitude of the radiation emitted by the diode during the time of travel of the missile toward the target. A further signal compares the signal which is proportional to the desired magnitude of the radiation with the signal which is proportional to the magnitude of the radiation emitted by the diode, and the difference between these signals is then used to control the amount of power supplied to the diode.
A method and device produce an optical link with laser pulses between an emitter of the pulses and a receiver of the pulses. The optical link is used by a locating device for locating a body moving at constant speed away from the locating device. The locating device delays the start of emission of the laser pulses with respect to the departure of the moving body and varies the energy of the successive laser pulses in proportion to the square of the time elapsed since the start of emission of the pulses.
