Crosstalk In Wavelength Division Multiplexed Systems Research Articles

SPM and XPM crosstalk in WDM systems with DRA: Channel spacing and attenuation effects

This paper presents a theoretical analysis of a closed formula for nonlinear crosstalk due to self-phase modulation (SPM) and cross phase modulation (XPM) in wavelength division multiplexing (WDM) systems. The influence of channel spacing and attenuation on the system behavior is modeled and investigated. The system under consideration is a standard single-mode fiber (SSMF) with a single-span distributed Raman amplifier (DRA) and is operating at 100 Gbps.

Impact of PMD on four-wave-mixing-induced crosstalk in WDM systems

The impact of polarization-mode dispersion (PMD) on four-wave mixing crosstalk in wavelength-division-multiplexed (WDM) fiber systems is quantified on a commercial system. It is found that even a small amount of PMD reduces the benefit of using polarization-multiplexed channels for suppression of crosstalk. As a rule of thumb, it is suggested that polarization-multiplexed schemes are of significant interest only when system differential group-delay (DGD) is smaller than DGD <1/(4/spl Delta/f), where /spl Delta/f is the channel-spacing.

Statistical properties of stimulated Raman crosstalk in WDM systems

The crosstalk variance of stimulated Raman crosstalk in wavelength-division-multiplexing (WDM) systems is derived analytically in a closed-form formula for all systems with different walkoff length. The probability density function (pdf) of stimulated Raman crosstalk is found to be lognormal distribution (Gaussian distribution in decibel scale). Both power penalty and power limit induced by Raman crosstalk are evaluated and can be applied to single- and multispan WDM systems.

Interferometric crosstalk reduction by phase scrambling

Interferometric crosstalk, arising from the detection of undesired signals at the same nominal wavelength, may introduce large power penalties and bit-error rate (BER) floor significantly restricting the scalability of optical networks. In this paper, interferometric crosstalk reduction in optical wavelength-division multiplexing (WDM) networks by phase scrambling is theoretically and experimentally investigated. Enhancement of 7- and 5-dB tolerance toward crosstalk is measured in a 2.5-Gb/s transmission link of 100 km and 200 km of SSMF, respectively. This result proves the feasibility of optical networking in the local area network/metropolitan area network (LAN/MAN) domain while tolerating the relatively high crosstalk levels of present integrated optical switching and cross-connect technology. Experiment is in good agreement with theory. Recommendations on the use of phase scrambling to reduce crosstalk in WDM systems are given.

Return loss measurements of WDM filters with tunable coherent optical frequency-domain reflectometry

Reflectivity measurements of wavelength-division multiplexed (WDM) filters were performed with polarization independent coherent optical frequency domain reflectometry (C-OFDR). The spectral resolution of 0.012 mn allowed to characterize side lobe spacing and reflectivity with 90-dB dynamic range. The off-channel reflectivity was also measured for estimating the interchannel crosstalk in WDM systems and the experimental results were fitted to a theoretical equation, extracting the physical parameters of the filter.