Data dependent phase coding for mitigation of intrachannel four wave mixing

A novel phase code for the diminution of ghost pulses is introduced. Our approach involves the use of a data dependent code and is intended to take care of the small ghost pulses that remain after, previously proposed, duobinary or alternate mark phase flipping are applied. Formerly suggested codes are quite powerful in tackling the strong pulses, but are not as efficient in preventing ghost pulses that occur in multiple consecutive spaces surrounded by marker blocks. Our coding method comes down to dividing each marker block into doublets and inverting the phase of every other doublet by π while keeping the marker blocks anti-symmetric. around single 0-bits or zero-blocks consisting of odd number of zeros.