Significant uncompensated reach extension of highly chirped 10-Gbit∕s directly modulated lasers is demonstrated by use of optical filtering provided by optical demultiplexers at the link end. Narrowband filtering narrows the optical spectrum of the chirped signal to minimize dispersion effects when the filter's center wavelength is appropriately adjusted relative to the laser wavelength. We show that an equivalent reach improvement is obtained with a dense wavelength division multiplexing (DWDM) demultiplexer as the filtering agent with optimal filter-laser alignment. Experimental uncompensated reach lengths of greater than 100 km of Corning LEAF® fiber are demonstrated, without the need for forward error correction. This represents a reach improvement of up to 50% in comparison with nominally unfiltered signal transmission. We also examine the correlation of performance with the filter insertion loss derivative.
© 2005 Optical Society of AmericaPDF Article