High-power distributed Bragg reflector ridge-waveguide diode laser with very small spectral linewidth

We manufactured and investigated distributed Bragg reflector ridge-waveguide diode lasers having sixth-order surface gratings and an emission wavelength around 974 nm. The single-mode output power of the lasers with a total length of 4 mm exceeded 1 W. A very small spectral linewidth of 1.4 MHz (3 dB) consisting of a Lorentzian part of 146 kHz and a Gaussian part of 1308 MHz was measured using a self-delayed heterodyne measurement technique.