Low-loss fattened fusion splices between different fibres

Using a fattening technique which requires a flame with a long hot zone. Fibres with both different cladding diameters and NAs can be spliced with low loss. For instance, a standard 125/9.5 /spl mu/m telecommunications fibre (NA=0.11), can be spliced to an 80/5.3 /spl mu/m fibre (NA=0.21) with 0.1 dB loss.