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Abstract: The influences of dispersion maps on three major nonlinear effects (SPM, XPM and SRS) in distributed Raman amplified fiber transmission systems with periodic dispersion compensation are numerically investigated at identical nonlinear phase shift. The results show that compared with lumped amplification, distributed amplification tends to enhance the SPM/XPM induced penalties provided per span complete DC is used. However, these performance differences can be canceled out by means of optimal dispersion managements. Moreover, distributed Raman amplification can change the optimal dispersion maps for XPM effects. On the other hand, the impacts of SRS crosstalk are mainly determined by wavelength spacing and walk-off parameter, and the effects of dispersion management are quite limited. For a system with properly designed fiber dispersion characteristics, SRS induced waveform distortion can be well suppressed. [Copyright &y& Elsevier]

Abstract: In this paper we investigate the performance of a quasi-analytic synthesis approach for dispersion compensating optical finite impulse response filters. It is shown by eye opening penalty and optical signal to noise ratio penalty calculations that with this method the filters dispersion can be adjusted reliably and with low effort to compensate for a specific amount of residual chromatic dispersion in optical transmission systems. The maximum attainable dispersion is then only limited by the filter order and the free spectral range rather then by optimization problems within the filter design. [Copyright &y& Elsevier]

Abstract: The cross-phase modulation (XPM) effect in fiber links with dispersion compensated by chirped fiber Bragg gratings (CFBGs) is analyzed here for the first time. A continuous-wave (CW) signal, referred to as a probe, is used to investigate the impact of XPM on communication systems. The result shows that the XPM in systems using CFBGs as dispersion compensators is greatly suppressed, compared with that of systems using dispersion compensated fiber (DCF). The difference of the dispersion management between the system using DCF and that using CFBGs is demonstrated, too. [Copyright &y& Elsevier]

In the present paper, the highly efficient Raman amplification properties of a realistic and idealized dispersion compensating photonic crystal fiber (DCPCF) are described numerically. We have used an accurate full-vectorial finite element modal solver with hybrid curvilinear edge/nodal elements and anisotropic perfectly matched layers for an accurate modal characterization of the realistic as well as idealized DCPCF. A good agreement is observed between numerically evaluated and experimentally [P.J. Roberts, B.J. Mangan, H. Sabert, F. Couny, et al., J. Opt. Fiber Commun. Rep. 2 (2005) 435–461] measured dispersion values. A high peak Raman gain efficiency of 10.5 W−1 km−1 is obtained at 13.1 THz frequency shift for a 1455 nm depolarized pump. A DCPCF module of 1-km length can compensate for the dispersion accumulated over 70-km of conventional single mode fiber link with a residual dispersion of ±50 ps/nm and can provide an average gain of 7.6 dB with ±0.9 dB gain ripples over C-band. [Copyright &y& Elsevier]

Abstract: We have proposed and experimentally demonstrated a novel and simple configuration to generate a dark-RZ pulse by a Mach–Zehnder delayed line interferometer. We have also compared the transmission performance between the dark-RZ and bright-RZ pulse in the pre-dispersion compensation and post-dispersion compensation systems. Our experimental results have shown that the dark-RZ is more sensitivity to nonlinear effects than the bright-RZ pulse, and the power penalty will also be larger than that of the bright-RZ at the same BER. The experiment results have also shown that the dark-RZ pulse is not suitable for the signal transmission with pre-dispersion compensation. [Copyright &y& Elsevier]

The Bloch mode propagation through the chirped periodical structure is defined by its local dispersion relation. In a slowly varying structure its time delay is the integral of the local inverse group velocity along the propagation direction. The integration can be strongly simplified for linearly chirped structures if the assumption is made that the local dispersion relation is just a scaled and shifted version of the dispersion relation at the input. This assumption leads to exact solutions for the structures with locally uniaxial deformation and provides a good approximation for arbitrary structures with. small chirps. The approach is demonstrated for high index contrast chirped Bragg mirrors and complicated photonic crystal waveguide structures, including coupled waveguides and a slow group velocity waveguide. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we report the successful realization of c-band operable FBG-based Gires-Tournois etalon dispersion compensations where the dispersion tuning range has been more than doubled by the inclusion of an additional etalon. This results in a compact tunable dispersion compensator, which has the advantages of multi-channel operation, extremely low group delay ripple, and low cost. [Copyright &y& Elsevier]

Abstract: We report here an inherently gain-flattened, high-gain discrete Raman fiber amplifier design with 21dB net gain (±1.4dB gain ripple) over 25nm bandwidth. The amplifier design is based on a W-shape highly nonlinear fiber, in which, optimized spectral variation of leakage loss has been used to achieve inherent gain flattening of Raman gain. The proposed fiber has an additional advantage of having a high negative dispersion coefficient (∼−84ps/kmnm) over the operating range of wavelength and thus the designed discrete amplifier module, based on this fiber, is also capable of compensating dispersion accumulated in one span (70km) of transmission through G.652 fiber. Hence, the designed module is proposed as a composite amplifier and dispersion-compensating unit for 25nm bandwidth, which is capable of handling both attenuation and dispersion of one span of G. 652 transmission. [Copyright &y& Elsevier]

Abstract: We demonstrate the characteristics of the reflective type discrete Raman amplifier in the dispersion compensating fiber which is composed of a circulator and a Faraday rotator mirror. With the same dispersion compensation, the gain of the reflective type is higher than that of the conventional single-pass type. Moreover, the forward pumping is better than the backward pumping in the reflective type dispersion compensating Raman amplifier. We also show that, by using the reflective type configuration, the polarization mode dispersion of the dispersion compensating fiber can be almost compensated. [Copyright &y& Elsevier]

We demonstrate tunable chromatic dispersion in a 4×40-Gbit/s wavelength-division-multiplexed (WDM) transmission experiments using single sampled nonlinearly chirped fiber Bragg grating (NC-FBG) with negligible errors from higher order dispersion or two cascaded inverse sampled NC-FBG to cancel the higher order dispersion within the data’s bandwidth. In both the single FBG and cascaded FBG configurations, <3 dB penalty is achieved for all four WDM channels even though the eye is completely closed without compensation. [Copyright &y& Elsevier]

We present an optimization process for the apodization strength factor of fiber Bragg grating dispersion compensators. It will he demonstrated that a proper choice of the apodization strength factor results in minimum deviation of the dispersion from the required level, maximum reflection bandwidth and minimum group delay ripple impact, thus leading to a reduction of the Q-factor penalty of the dispersion compensating system. We also discuss the influence of the fiber link length in the determination of the optimum apodization strength factor, taking into account that shorter links minimize the group delay ripple amplitude, whereas the longer ones maximize the bandwidth of interest. It is determined that a fiber link length of ∼80 km can balance the requirements of group delay ripple impact and bandwidth. The results obtained through this analysis allow a faster modeling of the Bragg grating parameters in order to achieve an improved spectral performance, as well as a cost-effective fabrication process. [ABSTRACT FROM AUTHOR]

A novel fiber grating structure is proposed for the purpose of dispersion compensation. This kind of grating can be produced with a large chirp parameter and period sampled distribution along the grating length. There are multiple channels in the wide bandwidth and each channel has totally different dispersion and bandwidth. The dispersion compensation effect of this special designed grating is verified through system simulation. [Copyright &y& Elsevier]

In this paper we set forth new exact analytical superluminal localized solutions to the wave equation for arbitrary frequencies and adjustable bandwidth. The formulation presented here is rather simple and its results can be expressed in terms of the ordinary, so-called “X-shaped waves”. Moreover, by the present formalism we obtain the first analytical localized superluminal approximate solutions which represent pulses propagating in dispersive media. Our solutions may find application in different fields, like optics, microwaves, radio waves, and so on. [Copyright &y& Elsevier]

Analytical expressions for the output pulse broadening and eye-diagram power penalty of a chirped sampled Bragg grating (CSBG) dispersion compensator are derived. The result is applied to optimize the design of residue dispersion ratio in each channel and the total channel number of a fixed-length CSBG. The optimal residue dispersion ratio does not change when the channel number changes. The filter-induced pulse distortion will induce an additional eye-diagram power penalty and will give an upper limit for the channel number of 40-G+ systems. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 171–174, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10267 [ABSTRACT FROM AUTHOR]

This study proposes and demonstrates, for the first time, a directly modulated NTSC AM-VSB erbium-doped fiber amplifier (EDFA) -repeated system in the 1550-nm region that uses a directly modulated transmitter, a push–pull preamplifier, a half-split band, wavelength-division-multiplexing (WDM) techniques, chirped fiber grating (CFG) as a fiber-dispersion compensation device. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 214–218, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10279 [ABSTRACT FROM AUTHOR]