A 16-wavelength transmitter with 50GHz channel spacing was built by in
terleaving two externally modulated singlemode 8-channel waveguide-gra
ting-router multifrequency lasers. A poser penalty of < 0.4dB was meas
ured on all channels modulated at 2.5Gbit/s after transmission through
627km of conventional fibre (17ps/km/nm).