Frequency stabilization of a GaAlAs semiconductor laser to an absorption line of iodine vapor

A single mode GaAlAs semiconductor laser operating at around 830 nm has been locked in frequency to the center of an absorption line of molecular iodine vapor. A relative frequency stability of better than 10−9 was obtained for time periods longer than 1 s. This stabilization scheme increases the flexibility of wavelength selection. A method has been developed to estimate the stability when only one stabilized system is available.