GAAS-ALGAAS QW DILUTED WAVE-GUIDE LASER WITH LOW-LOSS, ALIGNMENT-TOLERANT COUPLING TO A SINGLE-MODE FIBER

We report on low-loss, alignment-tolerant coupling between a single-qu antum-well (SQW) GaAs-AlGaAs laser and a cleaved single-mode fiber, Th e laser was fabricated using conventional growth and processing techni ques, and did not involve any regrowth, The mode size in the transvers e direction was expanded by using a diluted waveguide structure, A but t-coupling efficiency of 66% was achieved against a theoretically poss ible 78% (which does not correct for Fresnel losses), In addition, lar ge alignment tolerances for a 1-dB excess loss of +/- 2.0 mu m and +/- 1.0 mu m were measured in the lateral and the transverse directions, respectively.