1.55 /spl mu/m single-frequency long-cavity fibre laser with /spl pi//2 phase shifted DFB mode selection

We have proposed and realised a new configuration of a single-frequency fibre laser which presents the combination of DBR and DFB lasers. It allowed us, using standard active fibre without exotic codopants, to achieve an output power as high as several mW. The realised lasers have small linewidth and demonstrate insensitivity to the presence of additional cavities.