Theory on multichannel CPFSK lightwave network with laser phase noise immunity

A direct-detection, frequency-division multiple-access (FDMA) lightwave network that is immune to the effects of both laser center frequency drift and phase noise without using complicated hardware is investigated. More users can be accommodated in this system because the effect of the laser phase noise is eliminated and the channels can be packed more closely than before. Signals with power beyond the threshold imposed by stimulated Brillouin scattering can be launched into single-mode fibers without deteriorating the system performance, since the system is independent of the laser linewidth that determines the power threshold under the scattering. As a result, more power can be distributed to each user, or more users can be supported for a given receiver sensitivity.<>