Transmission at 100Gbit/s channel rates can be realized either by serial approach, e.g. on-off-keying ( OOK ) or by differential-phase-shift-keying ( DPSK ), polarization multiplexing or multi-level concepts like differential-quaternary phase-shift keying ( DQPSK ), respectively.

In these modulation methods, the transmission candidates are divided into several channels(10*10G) and wavelength-division –multiplexed transmission system.

Single-channe l transmission is considered to be attractive for longer system lengths, since with single channel transmission a higher spectral efficiency can be achieved thus enabling a more effective use of the transmission line, although the realization of single channel transmission has many technical challenges .

In high-capacity optical transmission systems the cost per transmitted bit per second and kilometer can be reduced by using ultra fast electronic circuits instead of elaborate optical methods.

Transmission experiments based on electrical time division multiplexing ( ETDM ) at 100, 107 and 111 Gb/s were reported recently.

(1)107-Gb/s optical ETDM transmitter for 100G Ethernet transport
Winzer, P.J.; Raybon, G.; Duelk, M.;
Optical Communication, 2005. ECOC 2005. 31st European Conference on
Volume 6, 25-29 Sept. 2005 Page(s):1 - 2 vol.6

Fig.1 107-Gb/s WDM ETDM transmitter

(2)100 Gb/s ETDM Receivers

Ludwig, R.; Schubert, C.; Huettl, B.; Schmidt-Langhorst, C.; Derksen, Rainer H.; Moller, Michael;
Lasers and Electro-Optics Society, 2007. LEOS 2007. The 20th Annual Meeting of the IEEE