E. Desurvire

Synchronous in-line regeneration of wavelength-division multiplexed solitons signals in optical fibers

A new synchronization technique for simultaneous in-line modulation and regeneration of wavelength-division multiplexed (WDM) soliton signals in optical fibers is proposed. A specific wavelength-mapping rule makes synchronization compatible with frequency-guiding Fabry-Perot filters. As an example, a 4 x 10 Gbitys WDM regenerated soliton system is demonstrated numerically. We also show that the technique is fully compatible with dispersion management, which alleviates detrimental WDM collisions. Thus the possibility of combining wavelength-division multiplexing and regeneration opens up new perspectives for ultrahigh-bit-rate transoceanic soliton systems.

Fundamental information-density limits in optically amplified transmission: an entropy analysis

Fundamental information-density limits are evaluated for amplified systems, based on entropy analysis. It is shown that in-line amplification introduces information loss, which is more important in distributed than in lumped amplification. In the absence of any other degradation (such as that which comes from dispersion and nonlinearity), spectral efficiencies of 6¿14 (bits/s)/Hz represent theoretical limits for medium- and long-haul amplified systems.

All-Optical Regeneration: Principles and WDM Implementation

Publisher Summary Optical regeneration is a technique of promising potential in the context of the evolution of high bitrate systems. The current technology alternatives for optical regeneration, considering both the theoretical and experimental performance and the practical component implementation issues with emphasis on the Wavelength–Division Multiplexing (WDM) applications, has been reviewed in the chapter. It discusses the signal degradation causes and the introduction of the 3R regeneration concept. The chapter also describes the regeneration techniques using the nonlinear gates and synchronous modulation. Furthermore, the chapter compares electronic and optical regeneration and engineering and economic implications of the high-capacity WDM systems. A 3R regenerator is in itself a subsystem, which implies a high level of reliability, with enhanced supervision and monitoring requirements. It is noted that the regenerator operation is ideally independent of the type of transmission line and data format. Optical regeneration offers a unique possibility for simultaneous WDM-channel regeneration, as opposed to the classical optoelectronic approach. However, this requires the WDM channel resynchronization and identical transmitter clocks for all channels.

Dual-control nonlinear-optical loop mirrors for all-optical soliton synchronous modulation.

A novel dual-control configuration of nonlinear loop mirrors is used for all-optical soliton synchronous regeneration. Simulations show substantial improvement in transmission in this device compared with singlecontrol devices, owing to chirp-free modulation. The absence of chirp is confirmed experimentally through a spectral analysis of the dual-control modulator.

A quantum model for optically amplified nonlinear transmission systems

Abstract We present an original quantum model describing the generation and accumulation of both amplification and nonlinearity noises in long-haul WDM transmission systems. Predictions are obtained for bit-error rate floors and optimal information-capacity performance in both terrestrial and transoceanic systems.

Effect of synchronous modulation on the soliton optical phase

We show that soliton regeneration through synchronous modulation reduces both amplitude and optical phase noise in a squeezinglike fashion. However, control of optical phase noise is found not to be sufficient to permit error-free phase-shift-keyed soliton transmission, as confirmed by numerical simulations.

40 Gbit/s polarization-independent, push-pull InP Mach-Zehnder modulator for all-optical regeneration

A polarization independent, push-pull InP Mach-Zehnder modulator for 40 Gbit/s all-optical regeneration was implemented. Error-free regenerated transmission over more than 20,000 km is demonstrated. Wavelength independence and immunity to crosstalk is also measured, showing potential for WDM transmission applications.

Feasibility of 1-Tbit/s (25 x 40 Gbit/s) transoceanic optically regenerated systems.

The feasibility of 1-Tbit/s transoceanic systems based on in-line optical regeneration of 40-Gbit/s channels is numerically investigated. The roles of fiber dispersion, fiber mode area, and channel and regenerator spacings are analyzed, and the corresponding operating ranges for error-free transmission are determined. The results represent a first step in designing multi-terabit-per-second global transmission systems based on realistic components and parameters.

Synchronously modulated soliton systems: a simple analysis of timing-jitter statistics and bit error rate

Summary form only given. Regeneration of soliton signals through synchronous phase or intensity modulation (PM or IM) causes dramatic reduction of jitter and amplitude noise, therefore enabling unlimited propagation distances. Through perturbation theory and extensive numerical simulations, it was shown that after regeneration, the output statistics of the jitter are non-Gaussian. In this paper, we derive through a simpler and analytical method the non-Gaussian probability density functions (PDF) for PM or IM. We use them to evaluate the respective deviations in bit error rates (BER) with respect to the Gaussian PDF approximation.

Error-free 20-Gbit/s soliton transmission over 7150 km through all-optical synchronous phase modulation

In the perspective of ultrahigh bit-rate (>100 Gbit/s) long-haul soliton transmission, synchronous regeneration requires all-optical clock recovery and all-optical modulation. All-optical amplitude and phase modulators have been proposed. However, regeneration based on phase modulators has been demonstrated only at 2.5-Gbit/s data rates. In this paper, an all-optical Kerr modulator has been implemented in a recirculating loop to periodically achieve phase control of 20-Gbit/s soliton data. Error-free propagation over 7150 km is achieved without the help of dispersion-managed fibers.