25 kHz narrow spectral bandwidth of a wavelength tunable diode laser with a short waveguide-based external cavity

We report on the spectral properties of a diode laser with a tunable external cavity mirror, realized as an integrated optics waveguide circuit. Even though the external cavity is short compared to that of other narrow bandwidth external cavity lasers, the spectral bandwidth of this tunable laser is as small as 25 kHz (FWHM). The side-mode suppression ratio (SMSR) is 50 dB. The laser is able to access preset wavelengths in 200 mu s and can be tuned over the full telecommunications C-band (1530-1565 nm).