Minimum shift keying (MSK) is used as the coding scheme in a high bit rate
optical transmission system, and the signal format is either RZ
(return-to-zero) or NRZ (non-return-to-zero). The system can combine
multiple individual channels with different wavelengths in a WDM or dense
wavelength division multiplexed (DWDM) arrangement. Dispersion management
can be provided using several techniques, such as quasi-linear
transmissions or conventional RZ transmissions. At the transmitter, an
optical MSK transmitter is used to modulate the phase of a stream of high
bit rate (e.g., 40 Gbit/s) optical signals. Many such data streams can be
combined in a wavelength division multiplexer and transmitted to a remote
receiver, where the signal is wavelength division demultiplexed. The
encoded data in each wavelength channel is then recovered by an MSK
receiver, which may consist of a delay demodulator and a balanced
detector.