Direct modulation of a distributed feedback laser for 40-Gbit/s very-short-reach optical links

We demonstrated direct modulation at 40-Gbit/s using a commercially available 1.3-/spl mu/m DFB laser. Clear eye opening observed for a bias current of up to 100 mA and output power of more than 11 dBm. BER measurements showed error-free operation. BER improvement was obtained for a negative dispersion fiber. These results indicate that directly-modulated DFB lasers have good potential for use as a cost-effective light source in VSR optical links.