Simultaneous stabilization of the frequency and power of an AlGaAs semiconductor laser by use of the optogalvanic effect of krypton

The frequency of an AlGaAs semiconductor laser operated in the 0.77 μm region has been locked to the optogalvanic signal of Kr I at 7694.5401 Å. By use of a feedback loop to the injection current source, the frequency stability of has been obtained for the 1 s averaging time and of for 240 s. The output power and frequency have been simultaneously stabilized by a combined use of feedback loops to the temperature controller and the injection current source. The drift of the power level for 20 min has been less than 1 μW under the frequency-stabilized condition. The power level adjustability at the frequency-locked state has been discussed. The shift of the laser frequency caused by the power level control has been found to be within 2 MHz in the power dynamic range over 0.7-1.6 mW.