Continuous-band OFDM System for High Speed Optical Transmission
Project Award Date: 04-01-2010
Orthogonal frequency-domain multiplexing (OFDM) has been applied to optical transmission systems to increase the optical bandwidth efficiency and improve the tolerance to performance degradation effects such as chromatic dispersion and polarization mode dispersion. OFDM transmitters and receivers rely on high speed digital signal processing and A/D-D/A conversion. While OFDM systems operating at 20Gb/s have been demonstrated, further data increases will depend on advances in high-speed D/A conversion electronics. Nortel's electronic pre-compensation or post-compensation products for optical transmission systems use sophisticated CMOS technology and built-in high speed A/D-D/A converters.
It would be useful if this capability could be extended to implement OFDM systems. ITTC researchers will investigate a novel coherent band-combining technique to enhance the capability of OFDM systems. The concept is based on the use of a mutually coherent optical frequency comb, and each component of this frequency comb carries a group of OFDM channels. If orthogonally between adjacent groups can be maintained, a continuous optical bandwidth can be used to carry optical channels without the need of a guard-band between them. This will allow a much higher transmission data rate than the current DIA converter speed can provide. It will also make the transmission data rate flexible without sacrificing the bandwidth efficiency.
Primary Sponsor(s): CIENA Corporation