Performance of WDM ring and bus networks in the presence of homodyne crosstalk

Theoretical Insights Into the Impact of Coherent and Incoherent Crosstalk on Optical DPSK Signals

“…In [13] it is emphasized that coherent crosstalk causes fading of the received optical power and shown by experimental and simulation means that the -factor fluctuates in a stochastic way. The fact of the coherent crosstalk being the cause of random fluctuations on the received optical power is also evidenced by other authors [5], [14]. The later reference also provides analytical and numerical probability density functions (PDFs) for the received powers and demonstrates that in the presence of coherent crosstalk the power penalties used to characterize the system performance are no longer deterministic, as happens in scenarios based on the incoherent crosstalk.…”

“…As the phase offsets are uniformly distributed on , then it can be shown that the variances of and are given by [14] (A4)…”

“…A number of special cases are of particular interest. Firstly, for an ideal matched optical filter, , and (11) reduces to (13) Furthermore, when the multipath crosstalk can be neglected , one sees that (13) leads to the well-known expression for DPSK, this is (14) Finally, for a channel without coherent crosstalk and for , (11) leads to (15) which is similar to the expression reported in ( [11], (5)) for an optical matched filter reception in the presence of the two ASE noise polarizations.…”

“…On the contrary, only a few studies have dealt with multipath coherent crosstalk [13], [14], and only recently its impact on direct detection DPSK systems has been assessed [15]. In [13] it is emphasized that coherent crosstalk causes fading of the received optical power and shown by experimental and simulation means that the -factor fluctuates in a stochastic way.…”

“…The later reference also provides analytical and numerical probability density functions (PDFs) for the received powers and demonstrates that in the presence of coherent crosstalk the power penalties used to characterize the system performance are no longer deterministic, as happens in scenarios based on the incoherent crosstalk. Reference [15] uses some of the findings reported in [13] and [14], namely the fact of the received optical signal in presence of multipath interference could be described using Rician statistics, as the basis for developing a new treatment for evaluating the impact of coherent crosstalk on DPSK signals and derives analytical formulas for both the moment generating function (MGF) of the decision variable and error probability, by using the well-known wideband optical filtering assumption [16] to model the optical receiver.…”