Control of a pumping diode laser

Abstract

To maintain substantially constant the temperature of a diode junction of a pulsed, cooled, diode laser and hence the wavelength of the optical output of the laser, which laser is used for optically pumping a main, pulsed, solid state laser, the diode junction is heated by an external source during inactive intervals between pulses of the diode laser. This heating, which preferably is achieved by passing a heating current through the diode junction, is adjusted to ensure that, per a unit time greater than the length of an inactive interval, the heat energy received by the diode junction from this external heating together with the heat energy generated in the diode junction itself by the pulses is substantially constant independent of the length of the inactive intervals. Preferably the heating current has a constant level except for a period after each pulse when the level is reduced, e.g. to zero. To achieve the constant total heating of the diode junction, this period has a length such that the heat energy denied to the diode junction during this period is substantially equal to the heat energy generated in the diode junction during a pulse. The arrangement permits variation of the pulse repetition rate of the main laser at will without adverse effect on its pumping by the diode laser.

Dependencies are inferred from the claim text.