GaAs-AlGaAs QW diluted waveguide laser with low-loss, alignment-tolerant coupling to a single-mode fiber

We report on low-loss, alignment-tolerant coupling between a single-quantum-well (SQW) GaAs-AlGaAs laser and a cleaved single-mode fiber. The laser was fabricated using conventional growth and processing techniques, and did not involve any regrowth. The mode size in the transverse direction was expanded by using a diluted waveguide structure. A butt-coupling efficiency of 66% was achieved against a theoretically possible 78% (which does not correct for Fresnel losses). In addition, large alignment tolerances for a 1-dB excess loss of /spl plusmn/2.0 pm and /spl plusmn/1.0 μm were measured in the lateral and the transverse directions, respectively.