A novel multilevel coding technique for high speed optical fiber communication systems

Abstract

This paper delineates a novel coding technique, a combination of coding and multiplexing technique, known as mapping multiplexing technique (MMT). A mapping algorithm is used to multiplex four channels, each of which running at 10Gbit/s. Up to four bits per symbol at a symbol rate of 10Gboud was successfully transmitted over a single wavelength. Compare to the conventional return to zero (RZ) and none-return to zero (NRZ)-time division multiplexing (TDM) more than 75% and 50% reduction in the spectral width are achieved, respectively. Calculated chromatic dispersion tolerance of ±130ps/nm is achieved for the 40Gbit/s MMT transmission system at the expense of ∼2dB degradation in the receiver sensitivity (compared to NRZ) due to an increase in the number of levels and in the signal dependency of signal-spontaneous beat noise. In comparison with conventional 4-ary system, the proposed system depicts ∼6.5dB improvement in terms of receiver sensitivity.