K. Kuboki et Y. Uchida, XPM EFFECT IN COHERENT FDM SYSTEMS USING FSK AND HETERODYNE-DETECTIONSCHEME, IEICE transactions on communications, E78B(5), 1995, pp. 654-663
Cross-phase modulation (XPM) induced by residual intensity modulation
in coherent optical frequency-shift-keying (FSK) frequency division mu
ltiplexing (FDM) transmission systems that use dispersion-shifted fibe
rs is evaluated theoretically and experimentally in terms of spectral
profile deformation. The bit-error rate is measured in a 2.5-Gbit/s 4-
channel 40-km dispersion-shifted fiber transmission experiment. and we
confirm experimentally and theoretically that the power penalty in th
e presence of residual intensity modulation of over 4 mWp-p exceeds 1
dB. Experimental results show that the penalty due to XPM is large eve
n when the power of the newly generated lights caused by four-wave mix
ing is 20-dB less than that of signals. This confirms that residual in
tensity modulation must be reduced in continuous-phase (CP)-FSK-FDM sy
stems even though they are designed to avoid generating four-wave mixi
ng.