Reduction of optical beat interference in SCM/WDMA networks usingpseudorandom phase modulation

A new approach is suggested to reduce the optical beat interference (OBI) in subcarrier multiplexed (SCM) wavelength-division multiple access (WDMA) networks. The idea is to deliberately introduce independent random polarization fluctuations in the electric fields transmitted on each optical channel. Random polarization results in an expanded OBI spectrum, and hence, less OBI power at the reference user receiving filter output. Electro-optic phase modulation is used to introduce polarization randomness in the fields before they are coupled into the fibers, A two-user system was simulated. Simulation results show the drastic reduction in OBI power spectral density using appropriate PN signals