High efficiency, long working distance laser diodeto singlemode fibre couplingarrangement

The authors describe a technique for coupling laser diode (LD) light into a singlemode fibre (SMF) which yields an efficiency as high as 85%, for uncoated micro-optics, with a working distance of 40 µm. The 1 dB excess loss alignment tolerances are ±0.9 and ±4 µm on transverse and optical axes, respectively. This is, to our knowledge, the best optimisation ever reported of the triplet ‘coupling efficiency, working distance, and alignment tolerances’ for an uncoated fibre micro-optics arrangement.