Analysis of intrachannel nonlinear effects in highly dispersed optical pulse transmission

Reduction of intrachannel four-wave mixing using subchannel multiplexing

“…To understand how subchannel multiplexing reduces FWM, suppose that the envelope of the electric field can be approximated by , where is the solution of the linear dispersive equation and where is a nonlinear perturbation [10]. The perturbation is the sum of the perturbations due to nonlinear forcing terms in the nonlinear Schrödinger equation, where denotes a pump pulse in the th bit slot.…”

“…FWM also transfers energy into the bit slots of the marks, inducing jitter in the energy of the marks [2]. When designing new systems, the effects of intrachannel FWM can be reduced by using low-nonlinearity slope-matched fiber, by optimizing the dispersion map, by choosing appropriate amounts of dispersion pre and postcompensation, and by using Raman amplification [3]- [5]. However, intrachannel FWM can also severely limit the propagation distance when installed systems are upgraded to higher per-channel data rates, as for example, when a terrestrial system is upgraded from 10 to 40 Gb/s.…”

Comparison of nonlinear phase noise and intrachannel four-wave mixing for RZ-DPSK signals in dispersive transmission systems

“…Figure 2 also shows the corresponding phase STD due to IFWM calculated by the method of [15]. For optical match filter, the STD from IFWM scales up by a factor of 3/2 = 1.22 for the √ 3 times increase in the width of IFWM ghost pulse [11], [12], [15]. Figure 2 also includes the corresponding result for nonreturn-to-zero (NRZ) signal at D = 0 [7], [16].…”

“…Due to fiber Kerr effect, from the model of [11]- [13], there is a nonlinear force of jγu k u l u * m from the collision of the k-, l-, and m-th pulses, where γ is the fiber nonlinear coefficient. The overall ghost pulse is equal to…”

“…NONLINEAR PHASE NOISE FOR RZ PULSES For a comparison to IFWM, nonlinear phase noise is evaluated based on the model of [11]- [15]. Assumed a Gaussian pulse with an initial 1/e pulse width of T 0 , the kth pulse along the fiber is…”