Transmission experiment at 3 Gbit/s with close-spaced wavelength-division-multiplexed single-frequency lasers at 1.5 μm

We report the first fibre-optic transmission experiment employing close-spaced wavelength division multiplexing and high-bit-rate modulation. Experimental results from transmission at 3 Gbit/s over 60 km of single-mode fibre using two wavelength-multiplexed single-frequency distri-buted-feedback lasers are described. The lasers, operating at 1.55 μm and with a wavelength separation of only 2.9 nm, are each modulated at 1.5 Gbit/s giving a total system capacity of 180 Gbitkm/s.