S. Walklin et J. Conradi, EFFECT OF MACH-ZEHNDER MODULATOR DC EXTINCTION RATIO ON RESIDUAL CHIRP-INDUCED DISPERSION IN 10-GB S BINARY AND AM-PSK DUOBINARY LIGHTWAVE SYSTEMS/, IEEE photonics technology letters, 9(10), 1997, pp. 1400-1402
It is shown through numerical simulation that residual frequency chirp
ing in lithium niobate external modulators, which accompanies devices
with a finite-optical extinction ratio, always degrades the performanc
e of lightwave systems that use optical AM-PSK duobinary signaling. Th
is is unlike binary systems which will exhibit either an improvement o
r degradation, depending on the polarity of residual chirp.