Single-transverse-mode filtering utilizing proton implantation: 1.3-W CW diffraction-limited unstable-cavity lasers at 1.48 /spl mu/m

We report the realization of a lossy filter utilizing ion implantation of the multiple-quantum-well (MQW) active layer along both sides of the ridge waveguide, and optimize the implantation process so as to enhance the diffraction-limited power level of our 1.48-μm unstable-cavity lasers. This enables at least 1.3 W of CW diffraction-limited power at 1.48 μm, which is the highest level ever reported for a structure without cavity-spoiling grooves.