Automatic system to control the operation of an extended cavity diode laser

This article describes an automatic system that permanently keeps an extended cavity diode laser (ECDL) frequency locked to a cesium line (852 nm). The ECDL has a new architecture based on an intracavity etalon. The laser power is 30 mW and the linewidth is narrower than 50 kHz. Two acousto-optic modulators finely change the laser frequency and optical power. The electronic control is composed of a computer, microcontrollers, digital analog converters, and direct digital synthesizers. The computer searches the ECDL parameters to tune it to the Cs line and closes the servoloop. It permanently checks the servoloop and relocks the laser if necessary. Both acousto-optic modulators are driven in real time by microcontrollers. They are programed in order to control the laser power and frequency with a predefined time sequence. This system, especially developed for an atomic fountain, can be easily adapted to a wide range of applications. (C) 2004 American Institute of Physics.