Time-frequency analysis of optical communication signals and effects of second and third order dispersion

Summary form only given. Channel data rates in optical communication systems are continually increasing with 40 and 80 Gbps rate systems under development today and bit-rates up to 640 Gbps demonstrated in laboratory experiments. Dispersive effects due to propagation through fiber and wavelength-division-multiplexing (WDM) channel filters distort optical signals, requiring dispersion compensation. In addition, systems with high data rates or WDM channels ranging over wide wavelength range also require dispersion slope compensation. We describe time-frequency analysis and measurements of amplitude- and phase-modulated optical signals. Such spectrogram representation of communication signals clearly shows spectral evolution of the signals, the effects of dispersion and dispersion slope on the signals, and can help in the design of spectrally-efficient, single or multichannel high-speed optical communication signals and systems.