Giovanni Bellotti

Cross-Phase Modulation Induced by OOK Channels on Higher-Rate DQPSK and Coherent QPSK Channels

In this paper we show that, in hybrid wavelength division multiplexed systems, the performance of high datatrate QPSK channels impaired by cross-phase modulation (XPM) induced by the lower rate OOK channels can be simply estimated by an extension of a well-known linear model for XPM, and novel analytical expressions of the sensitivity penalty are provided. From such a model we prove that the reported QPSK penalty decrease with QPSK baud rate increase should be attributed to the action of the phase estimation process rather than to the walkoff effect. The model also simply shows how coherent QPSK is more affected by XPM than incoherent DQPSK, and allows to infer that even more impact is expected when the baudrate is further reduced through polarization multiplexing.

Intensity distortion induced by cross-phase modulation and chromatic dispersion in optical-fiber transmissions with dispersion compensation

In dispersion compensated systems, the intensity distortion induced by the interplay between cross-phase modulation and fiber chromatic dispersion can be a primary cause of transmission degradation. This interplay is mostly studied by time-consuming computer simulations. This letter introduces a new model of this interplay in fiber transmissions with dispersion compensation, leading to a linear filter that, applied to the input intensity of a modulated interfering channel, gives the intensity distortion of a continuous-wave probe signal at the receiver. The model can be of significant value in the search for optimized dispersion maps.

Cross-phase modulation suppressor for multispan dispersion-managed WDM transmissions

We present a new suppression technique of the transmission impairments caused by cross-phase modulation in dispersion-managed links. This technique can be implemented through a simple, passive, and integratable device. Experimental results show a sensitivity penalty reduction from 4.3 to 0.1 dB in a two-channel 10-Gb/s transmission over three spans of 100-km positive nonzero dispersion-shifted fiber. We also show numerically the potential merits of the device with a large number of channels, merits which are expected to become more evident with the number of spans.

Dependence of self-phase modulation impairments on residual dispersion in 10-Gb/s-based terrestrial transmissions using standard fiber

We carry out, by computer simulation, an extensive investigation of the impact of residual dispersion on power margins induced by self-phase modulation in typical 5/spl times/100 km-long terrestrial transmission systems at 10 Gb/s, using standard single-mode fiber and modular dispersion compensation. We show that the most performing compensation technique is postcompensation, with positive residual dispersion, and that precompensation must be avoided in case of dual-stage amplification. We also propose a design rule to perform optimal dispersion compensation in multichannel transmissions.

Investigation of cross-phase modulation limitation over various types of fiber infrastructures

The impact of cross-phase modulation (XPM) on the transmission performance of a 2/spl times/10 Gb/s multiplex is characterized. In contrast to the other investigated fiber schemes, dispersion-compensated single-mode fiber is virtually not affected by XPM down to 50-GHz channel spacing.

10 x 10 Gb/s cross-phase modulation suppressor for multispan transmissions using WDM narrow-band fiber Bragg gratings

We present a 10/spl times/10-Gb/s cross-phase modulation suppressor based on series of WDM narrow-band fiber Bragg gratings. Its effectiveness is demonstrated in a 5/spl times/100-km transmission over nonzero dispersion-shifted fiber. When the device is inserted within the repeaters of the link, the observed bit-error-rate floor due to cross-phase modulation disappears, and a low penalty is obtained over a large range of residual dispersions, allowing the transmission of a larger number of channels over longer distances.

Analysis of cross-phase modulation induced intensity noise in high-speed dispersion compensated transmission systems

We introduce an improved theoretical model for the cross-phase modulation (XPM) induced intensity noise, and we evaluate the XPM-related impairments on 10 Gbit/s and 40 Gbit/s transmission systems with different dispersion compensation schemes.

Investigation of cross-phase modulation limitations on 10 Gbit/s transmission over various types of fiber infrastructures

We measure the impact of cross phase modulation (XPM) on the transmission performance of a 2/spl times/2 Gbit/s multiplex. In contrast to the other investigated fiber schemes, dispersion-compensated SMF is virtually not affected by XPM down to 50-GHz channel spacing.

Benefits of OTN switching introduction in 100Gb/s optical transport networks

In this paper we analyze the impact of introducing electrical OTN switching on top a WDM layer in two 100Gb/s optical networks. We evaluate cost and network efficiency improvements granted by OTN when using a multi-layer approach for the design. We demonstrate that OTN is a key ingredient for efficient 100Gb/s optical networking.

SPM/XPM-Induced Intensity Distortion in WDM systems

In high bit-rate multiwavelength optical transmission systems, self-phase (SPM) and cross-phase (XPM) modulation interact with the fiber chromatic dispersion producing intensity distortion on the transmitted signals.