Experimental studies of polarization-multiplexed optical OFDM superchannel transport
19 July 2010
Different schemes for generation of OFDM superchannels beyond 100 Gb/s capacity are introduced and recent experimental results of the transmission of OFDM superchannels over field deployed fibers are reported. Introduction Orthogonal Frequency Division Multiplexing (OFDM) has emerged as a very promising modulation format for high-speed and high-capacity optical transmission due to its high spectral efficiency and its resilience in the presence of fiber dispersion and PMD. Due to the almost rectangular shape of the optical OFDM spectra, multiple OFDM signals can be closely arranged in the frequency domain without guard intervals to form high-capacity superchannels [1], leaving the classical single carrier system architecture with fixed 50-GHz or 100-GHz channel grids. Various transmission experiments [2-5] have shown, that optical OFDM is capable to transport Tb/s capacities over several 100 km link length. In this paper we want to discuss different approaches to generate iFFT based high-capacity OFDM superchannels for experimental studies and highlight some recent results of transmission studies on OFDM superchannel transport. Generation of OFDM superchannels A major boundary for iFFT based optical OFDM systems is the available bandwidth of the electrical D/A-converters (DAC) at the transmitter, which typically convert the offline or in real time calculated OFDM signal from the digital domain into analog signals which are further used for the modulation of -25 -30 Power (dB) Power (dB)
