Micro-integrated 1 Watt semiconductor laser system with a linewidth of 3.6 kHz.

We demonstrate a compact, narrow-linewidth, high-power, micro-integrated semiconductor-based master oscillator power amplifier laser module which is implemented on a footprint of 50 x 10 mm(2). A micro-isolator between the oscillator and the amplifier suppresses optical feedback. The oscillator is a distributed Bragg reflector laser optimized for narrow-linewidth operation and the amplifier consists of a ridge waveguide entry and a tapered amplifier section. The module features stable single-mode operation with a FWHM linewidth of only 100 kHz and an intrinsic linewidth as small as 3.6 kHz for an output power beyond 1 W.