Analytical tools for evaluating the impact of in-band crosstalk in DP-QPSK signals

Abstract

An analytical tool based on the moment generating function of the receiver decision variable that can evaluate the impact of multiple in-band crosstalk signals in DP-QPSK (Dual-Polarization Quadrature Phase-Shift Keying) signals is presented. It is shown that when the number of interferers increases from 1 to 64 the crosstalk level, that assure a 2dB power penalty, becomes more stringent, -12 dB for the single interferer scenario and -15 dB for 64 interferers. The Gaussian approximation is also used for comparison purposes.

Physical Layer Impairments in Cascaded Multi-degree CDC ROADMs with NRZ and Nyquist Pulse Shaped Signals

“…Regarding the in-band crosstalk signals originated along the ROADM-based optical network, we consider that all interfering signals have the same modulation format and bit rate as the primary signal, but with different arbitrary transmitted symbols, characterized by a phase difference and a time misalignment between the primary signal and in-band interferers (Cancela et al, 2016). These interfering signals arise from the ROADM inputs and from the ROADM add structures, denominated, respectively, , and , , with M indicating the ROADM node and R the ROADM degree in which they are originated.…”

“…In this section, the evolution of the in-band crosstalk level along a cascade of 32 CDC ROADMs is evaluated for A = −40 dB, several ROADM degrees, considering both ROADM architectures, different add/drop structures and NRZ and Nyquist pulse shaped signals. The crosstalk level, at each ROADM output, is defined by *, = + ,, + , ⁄ , where + ,, is the average power of all interfering signals and + , is the primary filtered signal average power, at the output of the M th ROADM (Cancela et al, 2016).…”