Results for a simple, exact frequency synthesizer for dense wavelength-divi
sion multiplexing (WDM) are reported. Channel selection over >1-THz range w
ith programmable channel spacing up to 25 GHz and absolute optical frequenc
y referencing is achieved using widely tunable sampled grating distributed
Bragg reflector (DBR) lasers, injection-locked to an amplified fiber loop c
omb generator.