Heterodyne frequency measurements of a voltage-controlled diode laser

A single-mode GaAlAs diode laser is frequency stabilized by keeping the injection current and the voltage across the laser constant. The stability of the laser is studied by heterodyning it with another laser locked to the center of a hyperfine transition of the D/sub 2/-line of /sup 85/Rb. Alternatively, the frequency stability is observed by tuning the voltage-controlled diode laser to the center of an absorption line of rubidium vapor and recording changes in the absorption signal. In both cases a long-term frequency stability of 4*10/sup -8/ is observed.<
>