Low loss, alignment tolerant coupling from a GaAs/AlGaAs QW laser to a single mode fiber

In this paper, we propose and demonstrate a simple GaAs-AlGaAs SQW laser employing conventional growth and processing techniques. In this laser, the transverse spot size has been increased by the use of a diluted waveguide (Al mole fractions are graded from 30% in the core to 31% in the cladding). This laser butt-couples into a cleaved single mode fiber with only -2.8 dB loss, and has a -3 dB excess loss misalignment tolerance of /spl plusmn/3.4 /spl mu/m in the lateral and /spl plusmn/1.6 /spl mu/m in the transverse directions. The laser showed a T/sub 0/ of 112 K, indicating that the leakage of carriers is not very significant.