External-cavity-controlled 32-MHz narrow-band cw GaAlAs-diode lasers

By coupling a cw GaA1As-diode laser to an external resonator with Fabry-Perot etalons as dispersive elements, emission was reduced to a single-axial mode of 32-MHz width. The wavelength could be coarsely tuned over a spectral range of over 10 nm. Fine tuning over about 500 MHz was achieved by varying the external cavity length by less than lambda/3. At single-axial-mode operation, the commonly observed high- and low-frequency self-pulsing of the light output was found to disappear almost completely.