Asymmetric twin-waveguide 1.55-mu m wavelength laser with a distributed Bragg reflector

We demonstrate a single frequency, 1.55 mu m wavelength laser based on an a symmetric twin-waveguide structure using a single growth step and a simple fabrication process. The external Bragg grating is formed on the passive ri dge waveguide, optically coupled to the twin-guide gain section using a low loss, tapered mode transformer. The grating is produced by near-field holo graphic printing using a phase mask. Output powers >11 mW in a small-spot w aveguide with a side-mode suppression ratio >40 db and a slope efficiency o f 0.11 W/A are obtained under pulsed operation. These performance character istics are comparable to conventional, nonintegrated, conventional discrete DBR lasers, although the twin-waveguide design is compatible with photonic integrated circuits such as monolithic transmitters and WDM coherent recei vers.