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The laser-induced damage observed in optics has rendered compressor grating the most limited component in petawatt (PW) lasers, owing to the considerable challenges associated with manufacturing gratings possessing both a sufficiently high damage threshold and large dimensions. An asymmetric four-grating compressor (AFGC) based multistep pulse compressor method was proposed recently to alleviate the requirement of such gratings. The viability of AFGC is further investigated experimentally in SEL-100 PW frontend with spectral bandwidth of over 200 nm in this study. It is verified that the AFGC has the ability of beam-smoothing resulting from the introduced spatial dispersion. Meanwhile, the spatial dispersion scarcely impacts temporal contrast and focal spot of the output beam. By reducing the laser spatial intensity modulations from 2.0 to 1.3, the pulse energy capacity of the AFGC can be increased by more than 1.5 times through simple translation. The results mark a breakthrough toward experimentally renovating the grating compressor, and pave the way for a reliable and efficient constructions of 100 s PW lasers. [ABSTRACT FROM AUTHOR]

A new approach to a dispersive Michelson interferometer (DMI) is introduced. Rings of Equal Chromatic Order (RECO) are formed by a DMI illuminated by a white light source and crossed with an auxiliary dispersion spectrograph. The theoretical foundations are developed and then applied to different glass plates (BAK1, BK7, N-LAF35 and SK4) of thicknesses (12.101, 12.473, 9.930 and 6.602 mm), respectively. The sample is introduced in one of the arms of the interferometer. The refraction and dispersion of the samples are deduced from a single RECO interferogram. The refractive index and its variation are measured across the spectral range: 0.500–0.650 µm with relative errors of 10 −3 and 1.6 × 10 −4 , respectively. A good agreement between our measurements and reference data is found. [ABSTRACT FROM AUTHOR]

Abstract: Coupled resonator optical waveguides (CROW) comprised of only a few resonators including one defective element are investigated analytically and numerically. The defect is introduced by perturbing weakly the resonator at the center of the chain, creating a ‘cavity’ in what is an analogue of a Fabry–Pérot resonator or a defect-assisted photonic crystal structure. The device is found to have a very narrow resonance within the original stopband of the unperturbed CROW, and an accompanying extremely large group velocity excursion, that extends over both the subluminal and the superluminal ranges. The properties of the resonance and the magnitude of the group velocity dispersion are found to be conveniently controllable by coupling strength and by the number of resonators used. The perturbation can be caused thermo-optically or electro-optically. The complex effects of waveguide loss are extensively discussed. [Copyright &y& Elsevier]

Abstract: The purpose of this article is to analyze the impact of an index segmentation on the ray dispersion in the geometrical approach. The presented study reveals that a periodic index segmentation of the waveguide along with a transverse gaussian index variation exhibits complex ray dynamics that strongly modify ray dispersion properties. [Copyright &y& Elsevier]

Abstract: Considering the anisotropic dispersion model, the upper state population and spontaneous emission spectrum of three-level lambda-type atom with two transitions coupled to separate reservoirs are investigated using the resolvent operator. The upper state population reaches to a steady state value after a weak oscillation when the decay rate is zero and one transition frequency is inside the bandgap. The spectrum associated with each transition was given. Compared with results that were obtained by using isotropic dispersion model, the shape of spectrum changes significantly, and no dark line appears in the spectra. [Copyright &y& Elsevier]

Abstract: We present here some fundamental but yet underlooked features of the propagation of weak ultrashort pulses (with Δ d τ <<1, where Δ d is the Doppler width and τ is the pulse duration) in resonant atomic media. We show that the pulse area behaviour and the pulse spectrum at resonance are governed by the usual optical depth (α 0 L, where α 0 is the absorption coefficient at resonance and L the length of the medium), whereas the pertinent parameter that governs the severity of the dispersion effects and the distortion of the pulse is the dispersion parameter e disp =(α 0 L)Δ d τ that we introduce. Paradoxical effect such as distortionless propagation (e.g. e disp <<1) with vanishing pulse area (when α 0 L >>1) can then explained within this formalism. [Copyright &y& Elsevier]

Abstract: By means of a zigzag-wave model, we perform a comprehensive analysis of the guided modes of a photonic bandgap slab waveguide that consists of a low-index guiding layer placed between two different Bragg reflectors. We show that the guided modes of the waveguide operate inside the overlapped bandgaps of the two Bragg reflectors. We label each mode with three mode orders, which reflect the features of the mode-field distribution in the guiding layer and the two Bragg reflectors, respectively. We discuss in detail the transmission characteristics of the guided modes, including the dispersion curves, the cutoff conditions, and the confinement factors, and highlight the mode-selection characteristics of the waveguide. We also study the effects of truncating the Bragg reflectors by deriving an analytical expression to show the dependence of the leakage losses of the modes on the numbers of the periods in the truncated Bragg reflectors. [Copyright &y& Elsevier]

Abstract: A novel all-fiber asymmetrical Sagnac loop interferometer (ASLI) is proposed to measure the chromatic dispersion of a multi-channel fiber Bragg grating (FBG). Theoretical analyses to this proposed approach are presented in details. With this method, the chromatic dispersion and dispersion slope of a 51-channel FBG are simultaneously measured. The experimental results agree well with the ones obtained by using the general phase-shift method (PSM). This method has the advantages of simple configuration, low-cost, and high tolerance for the characteristics of FBG. [Copyright &y& Elsevier]

Abstract: The invention of the slot waveguide had enabled a number of interesting novel linear or nonlinear optical applications by guiding light in nanometers-wide low index slots guarded by high-index slabs. As one of its key characteristics, the low modal index for this kind of waveguides has been demonstrated by many studies. However, their higher order dispersion properties have not been thoroughly investigated yet, while the growing size and complexity of these devices and their potential nonlinear optical applications involving short optical pulses demand further understanding in their dispersion behavior. We here carry out a numerical study on the higher order dispersion characteristics of the SOI-based slot structures around the 1550nm wavelength. Our results show that they could have significantly different second order dispersion properties in contrast to the traditional channel SOI waveguides. Their potentially large normal dispersion could have an impact on various nonlinear or linear applications. The relationship between the dispersion performance and the waveguide design is also investigated, and the results could show further venues to optimize or control the dispersion properties of such waveguides. [Copyright &y& Elsevier]

Abstract: In long-haul frequency-division-multiplexing lightwave transmission systems, transmission characteristics are degraded by four-wave mixing (FWM) generated in optical fibers. To overcome this problem, several FWM suppression techniques have been reported. In this paper, dependence of FWM noises on frequency allocations, polarization allocations, and the zero-dispersion frequency is investigated. It is revealed that FWM noises are drastically decreased in frequency allocations such as equally spaced, repeated unequally spaced (RUS), equally spaced RUS, and unequally spaced RUS allocations by arranging polarization allocations of the channels with an increase in a separation between the channel frequencies and the zero-dispersion frequency. [Copyright &y& Elsevier]

Abstract: A parabolic index dispersion decreasing fiber (DDF) has been designed and optimized to produce high capacity soliton communication system. Variation of different fiber parameters such as core radius, effective core area and GVD factor along the 25km of DDF length has been carried out to optimize a best possible DDF which can sustain the propagation of fundamental soliton. The variation of non-linearity with length along with the conventional power and GVD factor variation has been included in the generalized non-linear Schrodinger equation (NLSE). This NLSE has been solved numerically by split step Fourier method for shorter pulse propagation, incorporating the term for third order dispersion and intrapulse Raman scattering. Stable soliton pulses in transmission system have been achieved by our simulation, when a correction factor due to Raman induced soliton mean frequency shift is incorporated to the GVD profile predicted by the fundamental soliton condition. The interaction of neighboring soliton pulse pair through the proposed fiber has also been studied. [Copyright &y& Elsevier]

Abstract: Spectrally and spatially resolved interferometry has become a powerful tool for measurement of relative phase shift of broadband laser pulses propagating through any dispersive medium. Since under usual experimental conditions the relative phase shift is due to the medium only, the values of group delay, group delay dispersion and the third order dispersion provide the common ultrafast dispersion constants for the given material. In this paper a detailed description of the state of the art of spectrally and spatially resolved interferometry is given. With the consideration of the effects of wavelength calibration, bandwidth of the light source, electrical and optical noises, curved wavefronts, visibility of the fringes, and mechanical vibrations of the interferometer, we show that the accuracy for the determination of group delay dispersion and third order dispersion can be as high as 0.1fs2 and 2fs3, respectively. [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: A new scheme with non-collinear sum frequency generation (SFG) process of broadband third harmonic generation (THG) with two KDP crystals (one doubler and one mixer) using angular dispersion was proposed. The principle of broadband harmonic generation with non-collinear angular dispersion was presented. The comparison between the schemes of non-collinear and collinear SFG process was performed. The effects of the angular dispersion on the conversion efficiency, the pulse shape and the spectrum of the third harmonic field were discussed. The results show that, if proper angular dispersion is added to the fundamental and the second harmonic field outside the mixing KDP crystal, respectively, the broadband third harmonic conversion efficiency can be improved significantly. However, the difficulty of this scheme arises due to the requirement of two gratings with different angular dispersion outside the mixer. With the new scheme, it can be simpler that only one grating is needed to realize the broadband phase matching in the non-collinear SFG process. Although the fundamental and the second harmonic field inside the mixing crystal are non-collinear except the center wavelength, a blazing grating with proper angular dispersion for the fundamental field (twice as that for second harmonic field) can yield the well compensation for phase mismatching in the SFG process. Consequently, the conversion efficiency and the characteristics of the third harmonic field for the broadband third harmonic generation can be improved significantly. [Copyright &y& Elsevier]

Abstract: A new electrical-domain precoder is proposed to mitigate polarization mode dispersion (PMD) in optical communications by modeling a PMD-dominant fiber optical channel using a single input multiple output (SIMO) channel. Employing a bank of finite impulse response filters and a polarization modulator, and using parameters derived from the Jones matrix representation of PMD, the proposed precoder efficiently adapts to the time-varying nature of PMD and simultaneously pre-equalizes both polarization modes at the transmitter. The transmitter-only structure avoids losing phase and polarization information due to the nonlinearity of the commonly used square law direct-detection receiver. Analysis is performed to evaluate the impact of channel mismatch due to feedback delay, channel estimation errors, and the impact of the finite length of the precoder filters. The analytical results are used to guide selection of the appropriate feedback rate for the adaptive system. Extensive simulation results confirm the efficiency of the proposed Jones precoder, and present it as an effective, low-cost replacement to the complicated, expensive optical-domain counter-parts. [Copyright &y& Elsevier]

Abstract: In direct sequence-optical code division multiplexing access (DS-OCDMA) system networks, data rate and data spreading technique involved in such systems require a high chip rate. Transmission link in these systems is significantly affected by the fiber chromatic dispersion. In this study, we have developed and employed a simple model to estimate the G652 fiber dispersion effects. OCDMA technique has been employed to investigate fiber chromatic dispersion effects on multiple access interference (MAI). We have found that, at a short optical fiber length, the optical fiber dispersion has a significant impact on the high data rate transmission systems (higher than 750Mbit/s). The performance and optimization of optical orthogonal code (OOC) in the OCDMA system is reported. We have demonstrated that, for a high data rate, even if dispersion compensated devices are not deployed, the BER can be significantly improved when the OOC desired length is selected. We have shown that when compensation dispersion devices are not deployed in the system, there is a trade off between the limited dispersion effects and the MAI. [Copyright &y& Elsevier]

Abstract: Nonlinear coefficient and group-velocity-dispersion of bismuth-based nonlinear fibers were determined by four-wave-mixing measurements. The wavelength dependence of refractive index of bulk bismuth-based glasses was also measured to estimate the material dispersion and waveguide dispersion. A newly developed bi-directional four-wave-mixing configuration enabled us to determine all fiber parameters simultaneously. The obtained fiber nonlinearity γ ∼1000W−1 km−1 of bismuth-based nonlinear fiber is the highest one in the step-index fiber made of oxide glasses as expected from a high refractive index at 1550nm. Dispersion analysis reveals that the both material dispersion and waveguide dispersion affect to the large group-velocity-dispersion of bismuth-based nonlinear fiber. [Copyright &y& Elsevier]

Abstract: Experimental results on supercontinuum generation in photonic crystal fibre tapers using pump pulses of 7ns duration at 532nm are presented. Photonic crystal fibre tapers with the first wavelength of zero dispersion around 532nm were fabricated. The generation of supercontinuum was investigated in normal and anomalous dispersion regimes. Supercontinuum spectra spanning more than 400nm in the visible region are reported. [Copyright &y& Elsevier]

Abstract: A femtosecond Ti:sapphire laser oscillator emitting pulses with 800nm central wavelength, 10.9fs pulse width, and 75MHz repetition rate, combined with a dispersion-compensated diffractive system, was used to implement a large-area, high-contrast, broadband optical interference technique based on the Talbot effect. Chromatic artifacts associated with the huge spectrum of the optical source (approximately 150nm) are compensated for with an air-separated hybrid diffractive–refractive lens doublet. The spatial resolution of the chromatically compensated Talbot images under femtosecond illumination is nearly identical to that achieved under continuous wave monochromatic illumination. Furthermore, the temporal width of the signal at the Talbot planes is limited by the group-delay-dispersion coefficient which is shown to be small. High-contrast one-dimensional periodic structures of 96.1μm spacing generated by Talbot diffractometry are experimentally demonstrated. [Copyright &y& Elsevier]

Abstract: A novel photonic crystal fibre (PCF) with a low confinement loss and nearly zero ultra-flatted chromatic dispersion and negative chromatic dispersion at a wide telecommunication window is presented. Important PCF design parameters, such as the effects of air holes and geometrical parameters on the effective index, confinement losses, chromatic dispersion and effective mode area, have been thoroughly investigated by employing the full vectorial finite element method. Significant reduction of the confinement loss and low chromatic dispersion of the PCF, with three rings of air holes, has been obtained by carefully incorporating additional air holes. [Copyright &y& Elsevier]

Abstract: The control role of the relative phase between the probe and driving fields on the gain and dispersion in an open three-level ladder atomic system with incoherent pumping and spontaneously generated coherence is investigated. It is shown that by adjusting the value of the relative phase, the switching from lasing with inversion to lasing without inversion (LWI) can be realized; high index of the refraction with zero absorption can be achieved. It is also found that when the driving field is on resonance, the dispersion curve versus the probe detuning is very similar to the gain curve if the relative phase corresponding to the dispersion advances π/2 than that corresponding to the gain. LWI gain from the open system is obviously larger than that from corresponding closed system. When the incoherent pumping is absent, the open system can get LWI gain, moreover the gain is larger than that when the incoherent pumping presents for suitable value of the relative phase, but the corresponding closed system exhibits only absorption. In addition, manipulation effects of atomic exit and ratio of the injection rates on phase dependent gain are also analyzed. [Copyright &y& Elsevier]

Abstract: We have theoretically investigated the transmission of the optical mm-wave generated by the double-sideband (DSB) intensity-modulation. According to our analysis and simulation, the data signals, carried by DSB optical mm-wave after transmission along fiber, are degraded greatly because of the fading effect and the time shift of the codes caused by the chromatic dispersion in fiber, and these effects limit the transmission distance of the signals. Our theory is confirmed by the experimental results. [Copyright &y& Elsevier]

Abstract: Transmission of polarized light through subwavelength slit apertures is studied in visible and near infrared range wavelengths. We examine the roles played by the slit apertures, such as length, depth, period and number of slits. The experiment results, including dispersion curves, demonstrate among other things that the surface plasmon polariton and Fabry–Perot waveguide modes collectively dictate the transmission properties of subwavelength slit arrays and that as they approach each other, not only large gaps are formed but also mode interconversion occurs. These findings are discussed and compared to theoretical predictions. [Copyright &y& Elsevier]

Abstract: We present a numerical stable method to easily compute bandgaps of one-dimensional complex basis photonic crystals using novel bandedge equations rather than the traditional dispersion equation. The bandedge equations are derived by the concept of scattering matrix and concisely expressed by the transport coefficients with operations of multiplication and addition only. It is not required to calculate the global transfer matrix or the cosine of Bloch phase to avoid numerical instability. Moreover, we present closed-form expressions to calculate the global scattering matrix without using recursive computation. Finally, numerical examples show that use of the derived bandedge equation has better numerical stability than using the traditional dispersion equation for the band structure analysis. [Copyright &y& Elsevier]

Abstract: The channelled spectrum employing polarized light interference is a very convenient method for the study of dispersion of birefringence. However, while using this method, the absolute order of the polarized light interference fringes cannot be determined easily. Approximate methods are therefore used to estimate the order. One of the approximations is that the dispersion of birefringence across neighbouring integer order fringes is negligible. In this paper, we show how this approximation can cause errors. A modification is reported whereby the error in the determination of absolute fringe order can be reduced using fractional orders instead of integer orders. The theoretical background for this method supported with computer simulation is presented. An experimental arrangement implementing these modifications is described. This method uses a Constant Deviation Spectrometer (CDS) and a Soleil Babinet Compensator (SBC). [Copyright &y& Elsevier]

Abstract: We present a simple method to measure the refractive index dispersion over a broad wavelength range (0.6–1.6μm). In a first step, the optical group indices are obtained by measuring the time-retardation of tunable 150 fs laser pulses within a sample relative to air. The refractive index dispersion is then calculated using a Sellmeier equation that describes the measured group index dispersion. We show that our experimental data agree with previously published results to within 2×10−4 for a 3mm thick sample of fused silica and to within 3×10−3 for the index n 1 of a 2mm thick crystal of the highly dispersive and anisotropic organic crystal 4-N,N-dimethylamino-4′-N′-methyl stilbazolium tosylate (DAST). [Copyright &y& Elsevier]

Abstract: An optical mm-wave demultiplexer is presented. Double sideband modulation with suppressed optical carrier and filtering properties of dual overwritten fiber Bragg gratings are the fundamentals for optical demultiplexing of mm-wave radio-on-fiber signals: using a single optical carrier, Millimeter-wave signals of 20 and 40GHz frequencies carrying independent data are created, transmitted over fiber, demultiplexed and wireless distributed to be detected and data recovered in a mobile unit. Double sideband modulation with suppressed optical carrier yields no power penalty due to chromatic dispersion, while the filtering properties of the dual overwritten fiber Bragg gratings allow less than −40dB electrical power interchannel leakage. Independent 2.5Gb/s On–Off-keyed data have been successfully transmitted through the 20 and 40GHz channels. [Copyright &y& Elsevier]

Abstract: In this paper, we propose a novel mismatched multicavity etalon (MME) all-pass filter for fixed-value dispersion compensation and dispersion slope compensation. It is a multicavity Gires-Tournois (GT) etalon filter with unequal cavity lengths between adjacent cavities. A theoretical study is presented. Analytical expressions for the group delay and chromatic dispersion are derived to allow device designs to be made. The simulation results show that nearly linear group delay or quasi-flat chromatic dispersion response can be obtained by suitably choosing the reflectances of the reflectors and the cavity mismatch length. The chromatic dispersions and the bandwidth of the quasi-flat-dispersion band can be tailored by changing the reflectances of the reflectors and the mismatched cavity length. The dispersion slope compensation can be obtained by slightly modulating the reflectances of the reflectors. Increasing the number of cavities can enhance the performance and the design flexibility of the dispersion compensator. [Copyright &y& Elsevier]

Abstract: An approximate analytical analysis is given describing the strongly nonlinear evolution of optical pulses in nonlinear fibres with normal dispersion. The result provides a good explicit description of the evolution of initially chirp-free Gaussian-shaped pulses, including the developing chirp and the successive pulse rectangularization that ultimately leads to wave breaking. [Copyright &y& Elsevier]

Abstract: An analytical direct matching procedure within the Kronig–Penney model was applied to analyse the dispersion behavior of the localized surface states supported in the surface of a semi-infinite one-dimensional photonic crystals truncated with a thin nonlinear cap layer. We find that the surface states are very sensitive to the nonlinearity of cap layer on the surface. [Copyright &y& Elsevier]

Abstract: The fiber Bragg grating with cladding made of uniaxial crystal material whose optical axis is parallel to the axis of fiber Bragg grating proposed in the paper published in 2003 was investigated again and an error was corrected in the calculation, its effective index, reflectivity and dispersion were examined using coupled-mode theory and numeric solution. The calculated results indicate that no low frequency cutoff phenomenon exists in the HE11 mode, more power is transmitted by the core of the fiber with cladding made of isotropic material, the reflectivity of the fiber Bragg grating with cladding made of uniaxial crystal material is much higher than that with cladding made of isotropic material, the parameter K cl, i.e., the ratio of the extraordinary to the ordinary ray refractive index, has a stronger impact on the reflectivity, Bragg wavelength and the dispersion of this kind of fiber Bragg grating when it varied from 1.00 to 1.01 than in other regions. This means that the characteristics of the fiber Bragg grating with uniaxial crystal cladding can be changed through adjusting K cl while keeping its length, periodicity and the other parameters as constants. [Copyright &y& Elsevier]

Abstract: In this paper, a rapid numerical difference recurrent formula, in which it has been taken that the chromatic dispersion and the nonlinearity act together along each fiber segment, is established in the time domain by applying a Maclaurin expansion to the differential form of the nonlinear Schrödinger equation (NLSE) in the frequency domain. The calculated results by using the established formula are contrasted with the known analytical results and the results of the split-step Fourier method (SSFM) and indicated that the rapid numerical difference recurrent formula is very accurate and more reasonable because it abandons an assumption that the dispersive and nonlinear effects can be assumed to act independently as the optical field propagates over each fiber segment. It has been concluded that the established formula in this paper is a scientific, reasonable and effective numerical method for the study of light pulse propagation in a nonlinear optical medium. [Copyright &y& Elsevier]

Abstract: We demonstrate efficacy of shaping Gaussian pulses into dispersion-managed (DM) solitons by dint of a device which includes two fibers with the same group-velocity-dispersion (GVD) coefficients as in the DM system, a frequency-domain filter, and an amplifier. The shaping of a given input pulse is optimized by adjusting values of four free parameters of the cell, viz., lengths of the two fibers, filtering coefficient, and amplification gain, with the objective to achieve the best fit of the transformed pulse to the (numerically found) DM soliton, including systems with the third-order GVD, and with three-step DM maps. Launching reshaped pulses into the DM system, we demonstrate, in direct simulations, their complete stability over indefinitely long propagation distances. We examine sensitivity of the reshaping to deviations of the control parameters from their optimum values, a noteworthy results being very weak dependence on variations of the filtering strength. The dependence of the four control parameters on the width and chirp of the Gaussian input signal is also studied in detail. [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]

Abstract: A robust, self-starting picosecond pulse source based on ytterbium (Yb3+) doped fiber laser is described. Utilizing a chirped-fiber-Bragg-grating (C-FBG) for dispersion control, solitary mode-locking is obtained without bulk dispersion compensation elements. A semiconductor saturable absorber (SESAM) is used for stable self-starting. 3.6ps pulses are produced, with 45MHz basic repetition-rate and mW scale average output power at 1060nm. Detailed numerical simulations based on the modified nonlinear Schrödinger equation agree well with the experimental results and are used as a design tool for the solitary mode-locked picosecond laser. The presented design can be simply employed in an all-fiber environmentally-stable system. [Copyright &y& Elsevier]

Abstract: We present a numerical method for compensating dispersion effects in optical coherence tomography that does not require a priori knowledge of dispersive properties of the sample. The method yields results equivalent to recently demonstrated quantum-optical coherence tomography, but without exploiting non-classical states of optical radiation. Dispersion compensation is accomplished by processing phase information present in standard interferograms to calculate the generalized autoconvolution function. The operation of the method can be conveniently visualized using the Wigner distribution function formalism. [Copyright &y& Elsevier]

Abstract: In this paper, we first derived the BER expression of an optical channel with chromatic dispersion impairment. The derived BER expression takes into account the influence of pulse spreading, transmitter rise/fall times, receiver Q-factor and noises. It is simpler and hence easier to use than many existing channel BER models. Then we proposed a wavelength-interleaved FEC scheme to mitigate the chromatic dispersion impairment in optical transmission system and analyzed its decoding performance. The minimum wavelength separation required for such a wavelength-interleaving FEC system to obtain the highest coding gain is also determined. Based on this design, the chromatic dispersion tolerance of the proposed system with 2-wavelength and 4-wavelength-interleaving are shown to improve by about 13% and 22%, respectively, over a non-interleaved system. In essence, wavelength-interleaving averages out the performances of a set of channels experiencing higher and lower dispersion, hence the interleaved channels have better performance than the non-interleaved channels experiencing higher dispersion, and worse performance than the non-interleaved channels experiencing lower dispersion. However, since WDM systems are typically designed based on the worst-case channel, the overall system performance is improved by wavelength-interleaving. [Copyright &y& Elsevier]

Abstract: The possibility of applying the Drude term in the interpretation of the optical rotatory dispersion of crystals with the optical activity of a crystalline origin is presented. Using the perturbation theory the presence of the Drude term in the optical rotatory dispersion relations derived for the modified models of coupled oscillators is proved. Necessary conditions define this Drude term application, i.e. for its use in the description of the optical rotatory dispersion of crystals consisting of the optically inactive particles. The presented theory is considered as the second limit in the calculation of the oscillator strengths of the normal modes of vibrations in comparison with the classical approach to them. The presented results are of use in the case of the α-quartz, whereas the application of the Drude term in the optical rotatory dispersion relations for tellurium crystal does not improve substantially the interpretation of the experimental data. [Copyright &y& Elsevier]

Abstract: The behaviour of the temporal Talbot effect under carrier partial coherence is analysed. This effect finds application as a passive method for multiplying the repetition rate of the intensity of pulse trains in first-order dispersive media. The study is based on the representation of the average intensity of partially coherent modulated light after first order dispersion as a coherence-dependent low pass filter acting on the intensity distribution obtained with a monochromatic carrier. The resulting coherence limitations are more restrictive in Talbot devices with high indices, due to the necessity of highly coherent carriers to produce a faithful reconstruction of trains by multiple pulse-to-pulse interference. Coherence limitations for architectures composed of externally modulated cw sources are analysed. Generalizations of the theory to several spectral lines, and its relation with the Collett–Wolf theorem are also reported. [Copyright &y& Elsevier]

Abstract: We report on a chromatic dispersion monitoring technique using a direct detection of high-speed chirped pilot tones. Unlike the previously proposed monitoring technique using amplitude-modulated (AM) and phase-modulated (PM) pilot tones, the proposed technique can discriminate the sign of accumulated dispersion. The results show that the performance of this technique could not be seriously deteriorated by polarization-mode dispersion (PMD) and self-phase modulation (SPM) since the tone frequency was small (∼2GHz). [Copyright &y& Elsevier]

Abstract: We analyse modulational instability (MI) of electromagnetic waves in a large variety of optical fibers having different refractive-index profiles. For the normal-, anomalous-, and zero-dispersion regimes of the wave propagation, we show that whenever the second-order dispersion competes with higher-order dispersion (HOD), propagation of plane waves leads to a rich variety of dynamical behaviors. Most of the richness comes from the existence of critical behaviors, which include situations in which the HOD suppresses MI in the anomalous dispersion regime, and other situations in which the HOD acts in the opposite way by inducing non-conventional MI processes in the normal- and anomalous-dispersion regimes. We show that non-conventional MI sidebands are more prone to Raman-induced degradations than ordinary MI sidebands can be. [Copyright &y& Elsevier]

Abstract: We report measurements of ultrashort optical pulse filamentation in Kerr media with normal dispersion. We measure the angular dispersion of spontaneously generated colored conical emission and show that for large frequency shifts from the input pump frequency, it is well described by a relation between angle and frequency with slope determined solely by material chromatic dispersion. This measurement is in agreement with recent models that interpret filamentation dynamics in terms of the spontaneous formation of nonlinear X-waves. Finally, experimental results of filamentation in air show, for the first time, that the interpretation of CE in terms of X-waves may be also extended to gaseous media. [Copyright &y& Elsevier]

Abstract: We demonstrate that chromatic dispersion and group delay ripple limit the performance of all-optical regeneration based on self-phase modulation. The level of degradation depends in detail on the type of phase distortions introduced. The regenerator performance is measured using the optical signal to noise ratio (OSNR) margin provided to the system for a given bit error ratio. The addition of chromatic dispersion and group delay ripple induces a significant reduction in this OSNR margin. [Copyright &y& Elsevier]

Abstract: Characteristics of the side-polished thermally expanded core (TEC) fiber have been investigated theoretically and experimentally. The effect of core expanding on the transmission of the side-polished TEC fiber is predicted theoretically and demonstrated experimentally. The side-polished TEC fiber covered with an external medium whose chromatic dispersion is much different from the fiber materials, is applied to a band-edge filter with a high cut-off. The relationship between the expanded core diameter and the performance of the band-edge filter was measured and discussed. [Copyright &y& Elsevier]

Abstract: We describe a class of spatio-temporal optical pulses that spread neither spatially nor temporarily in linear dispersive media over long propagation distances. These new spatio-temporal pulses, referred to as linear optical bullets, can have any spatio-temporal profile and temporal width, and they carry a finite amount of energy. We also discuss in detail a technique for the experimental realization of linear optical bullets. [Copyright &y& Elsevier]

Abstract: The pulse compression induced by cross-phase modulation in birefringent dispersion decreasing fiber is discussed theoretically by solving the coupled Schrödinger equations which include the contribution of the high-order non-linear effects, and third-order dispersion. In particular, it is found that a high quality compressed signal pulse can be obtained by a pump pulse of low intense through the technique. The dependence of optimum compression on the non-linear factor N, time delay and the dispersive ratio f is also discussed in detail. [Copyright &y& Elsevier]

Abstract: We develop a multi-dimensional simulation code based on the coupled wave equation for optical parametric chirped pulse amplification involving frequency chirp, beam divergence, walk-off effect, group-velocity mismatch, group-velocity dispersion, and diffraction. We demonstrate numerically transverse narrowing, spatial dispersion and central-wavelength shifting effects in the signal beam for a conventional noncollinear geometry. [Copyright &y& Elsevier]

Abstract: Recent advances in high intensity laser technology, such as the optical parametric chirped pulse amplification technique, allow the amplification of broadband pulses to high energies, by parametric interaction in a non-linear crystal. In this article, angular dispersion of the signal beam inside the non-linear media is added to a common setup to improve the non-collinear phase matching range. A comparative study of the performance of BBO, LBO and KDP using this geometry is undertaken. Computer simulations show that both BBO and LBO are excellent broadband performers. Although the maximum bandwidth of KDP does not broaden, we show how to avoid its severe narrowing below the degeneracy wavelength. [Copyright &y& Elsevier]

Abstract: The moment method is used to derive evolution equations for the energy, width and chirp of an optical pulse in a dispersive and dissipative (filtered) system. This method is conceptually simpler than the variational and soliton-perturbation methods, and allows the dispersion and dissipation coefficients to have arbitrary relative magnitude. The moment equations are used to study the effects of filtering on pulse dynamics and equilibria, and their predictions are compared to the results of numerical simulations based on the Ginzburg–Landau equation. [Copyright &y& Elsevier]

Abstract: The nonlinear Schrödinger equation is solved using the small signal analysis approach. In the resonant dispersion erbium-doped fiber amplifiers (EDFAs) of WDM systems, the crosstalk between signals and induced by signals are discussed. The resonant dispersion of EDFAs has a strong effect on the cross-phase modulation instability gain frequency, and causes severe crosstalk when the multiple signal channels are taken into account. In a WDM system, for most channels where the resonant dispersion occurs, the crosstalk powers induced by other channels’ XPM are stronger than the intensity modulation induced by XPM between the reference and other channels. The factors affecting crosstalk include signal power, nonlinear coefficient and channel separation. Pump power distribution can dominantly diminish crosstalk. To keep the system’s performance, the proper dispersion compensation is a better method to minimize the crosstalk. [Copyright &y& Elsevier]