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1.
Using the ray propagation model generalized expressions for the impulse response of multimode fibres have been derived. The analysis has been applied to lossless fibres for pulses having both gaussian and lambertian spatial distributions as well as impulse and gaussian temporal distributions. Detailed results are given for output pulse shapes and fibre dispersions for various configurations. 相似文献
2.
Nonlinear coupling of polarized solitons in birefringent optical fiber in the presence of third-order dispersion is considered in the framework of the coupled nonlinear Schrödinger equations. The influence of third-order dispersion on the interaction between solitons is investigated. For sufficiently strong third-order dispersion the interaction may even become repulsive. The stable conditions for solitons of partial pulses are analyzed and amplitude threshold, which decreases with third-order dispersion coefficient decreasing, for the capture of solitons of partial pulses into a coupled two-component pulse is obtained. 相似文献
3.
Lushnikov PM 《Optics letters》2000,25(16):1144-1146
A dispersion-managed optical system with stepwise periodic variation of dispersion is studied in the framework of a path-averaged Gabitov-Turitsyn equation. The soliton solution is obtained by means of iterating the path-averaged equation. The dependence of soliton parameters on dispersion map strength is investigated, together with the oscillating tails of the soliton. 相似文献
4.
Milorad M. Cvijetic 《Optical and Quantum Electronics》1984,16(4):307-317
An exact analytical approach to the synthesis of the refractive-index profile of dual-mode optical fibres with zero intermodal dispersion is presented, and the computer-aided, trial-and-error synthesis of the optimal profile is described. The synthesis is based on inverse scattering theory. Self-consistency of free potentials corresponding to individual modes was attained by numerical methods. The characteristics of the optical fibres with synthetized profiles were analysed, the optimization constraints were specified, and an optimum profile was found. The results can be used for the design of broadband optical fibres.Notation
(r), (r)
Single and double derivatives
-
C
l(r)
Determinant of a matrix det
-
k
l
(r)
Vector
-
k
l
(r)
l
(r)
The scalar products of the vectors
-
K
l(wr)
The modified Bessel function of the second kind
-
l(wr)
The modified Bessel function of the first kind
-
J
l(uaR)
The Bessel function of the first kind 相似文献
5.
The split-step Fourier method is used to study the energy switching characteristics of fiber nonlinear directional couplers with the third-order dispersion. The effects of the third-order dispersion increases with the third-order dispersion coefficient and input power and result in pulse shift and energy decreases. Adding high-order nonlinear can partly overcomes these effects. 相似文献
6.
We model the propagation of femtosecond pulses through optical fibres by a nonlinear Schrödinger (NLS) equation involving a perturbing term arising due to third-order dispersion in the medium. The perturbative effect of this higher-order dispersion causes the usual NLS soliton to emit a radiation field. As a result, the given initial pulse propagating through the fibre exhibits nonsolitonic behaviour. We make use of a variational method to demonstrate how an initial pulse by the interaction with the emitted radiation can evolve into a soliton. We also demonstrate that the effect of interaction between the initial pulse and radiation field can be accounted for by including, in the evolution equation, terms associated with self-steepening and stimulated Raman scattering that characterize the optical medium. 相似文献
7.
Dissipative Kerr solitons in optical microresonators with Raman effect and third-order dispersion 下载免费PDF全文
《中国物理 B》2021,30(5):54206-054206
Using the mean-field normalized Lugiato–Lefever equation, we theoretically investigate the dynamics of cavity soliton and comb generation in the presence of Raman effect and the third-order dispersion. Both of them can induce the temporal drift and frequency shift. Based on the moment analysis method, we analytically obtain the temporal and frequency shift,and the results agree with the direct numerical simulation. Finally, the compensation and enhancement of the soliton spectral between the Raman-induced self-frequency shift and soliton recoil are predicted. Our results pave the way for further understanding the soliton dynamics and spectral characteristics, and providing an effective route to manipulate frequency comb. 相似文献
8.
Ultrashort pulse breaking in optical fiber with third-order dispersion and quintic nonlinearity 下载免费PDF全文
The optical wave breaking (OWB) characteristics in terms of the pulse shape, spectrum, and frequency chirp, in the normal dispersion regime of an optical fiber with both the third-order dispersion (TOD) and quintic nonlinearity (QN) are numerically calculated. The results show that the TOD causes the asymmetry of the temporal- and spectral-domain, and the chirp characteristics. The OWB generally appears near the pulse center and at the trailing edge of the pulse, instead of at the two edges of the pulse symmetrically in the case of no TOD. With the increase of distance, the relation of OWB to the TOD near the pulse center increases quickly, leading to the generation of ultra-short pulse trains, while the OWB resulting from the case of no TOD at the trailing edge of the pulse disappears gradually. In addition, the positive (negative) QN enhances (weakens) the chirp amount and the fine structures, thereby inducing the OWB phenomena to appear earlier (later). Thus, the TOD and the positive (negative) QN are beneficial (detrimental) to the OWB and the generation of ultra-short pulse trains. 相似文献
9.
A time domain dispersion measurement apparatus was successfully built and tested at the Indian Institute of Technology, Madras. This instrument can measure directly the pulse broadening in a multimode optical fibre. The basic dispersion mechanisms in optical fibres and the design details of the system are discussed. 相似文献
10.
Kumar S 《Optics letters》2007,32(4):346-348
It is shown that the third-order dispersion of an optical fiber can be compensated for using a time-reversal system that can be implemented with periodic time lenses. 相似文献
11.
S. Divya V. P. N. Nampoori P. Radhakrishnan A. Mujeeb 《Applied Physics A: Materials Science & Processing》2014,114(4):1079-1084
Nanostructured TiO2 in different shapes such as nanosheet, nanowire, and nanoflower, as well as nanosphere have been prepared and characterized. Nonlinear optical (NLO) properties were measured at 532 nm using open and closed aperture Z-scan technique with respect to the shape. NLO behaviour of the nanostructured TiO2 is found to be shape dependent in suspensions at the investigated wavelengths and is accounted in terms of effective surface-to-volume ratio of the structures. The values of different optical constants viz, β,n 2,χ (3) for different morphological structures were evaluated and compared. The optical limiting thresholds of the samples were also investigated and it is found to decrease with increase in the net light matter interaction area of the sample. 相似文献
12.
We describe in this paper a frequency-domain measurement configuration allowing the determination of intermodal dispersion, differential mode attenuation and mode-coupling effects in graded-index optical fibres. Attention is mainly given to intermodal dispersion which is obtained with a resolution of 5 ps km–1 and a dynamic range of 15dB. Spatial (or modal) resolution is examined from both the theoretical and experimental point of view and the high degree of resolution of the experiment is illustrated. Interpretation of the results for deducing the index profile errors and correcting the preform manufacturing process shows the usefulness of the method for improving fibre quality. 相似文献
13.
We present a theory of chirped breathing pulse propagation in optical transmission systems with strong dispersion management. Fast changes of pulse width and chirp over one period are given by a simple model that is verified by direct numerical simulations. An average pulse evolution in the leading order is described by the nonlinear Schr?dinger equation, with additional parabolic potential that can be a trapping (when a grating is used) or a nontrapping (without a grating) type. 相似文献
14.
The effect of the third-order filter term on soliton interactions in optical fibers with guiding filters is theoretically analyzed. We find that this term causes a significant difference to the interaction of solitons through filters among the regimes of without sliding, with up- and down-sliding frequencies of filters. It is shown that the interaction between solitons can be more effectively suppressed by up-sliding filters than that by down-sliding filters in the presence of the third-order filter term. Moreover, the third-order filter term is found to play a positive role in suppressing soliton interactions in the case of non-sliding. 相似文献
15.
The characters of dense dispersion managed soliton in optical fiber transmission systems 总被引:1,自引:0,他引:1
The properties of ultra-short dense dispersion-managed soliton (DBMS) in optical fiber links are investigated. They show some excellent characters, such as, reducing pulse's breathing extent greatly, facing fewer mutual interactions and tolerating larger local dispersion. In general, DBMS is more stable than a conventional dispersion-managed soliton in high-capacity systems. Excessively dense dispersion compensation is more suitable for systems with weak nonlinear effect. 相似文献
16.
Using wave functions determined from ground-state local-density calculations, we have calculated the wave-dispersed free response of the optical nonlinear polarizability
(3)(–3;,,), for the C60 molecule and
(3)(–3;,,) i.e. Third-Harmonic Generation (THG) for films using a sum-over-states approach. The influence of screening was determined by applying an external static electric field in separate selfconsistent calculations to evaluate induced dipole moments which was used to determine the static linear and nonlinear polarizabilities. The polarizabilities calculated in the static limit were used to determine an effective screening parameter which was, in turn, used together with an RPA approach to calculate screened wave-dispersed, third-order nonlinear optical properties such as
(3)(–3;,,) and
(3)(–3;,,). Comparing evaluated polarizabilities with experimental values we found that the non-resonant free polarizability compares well in absolute magnitude with experimental results. Inclusion of screening results in a polarizability about two orders of magnitude below the experimental values.Paper presented at the 129th WE-Heraeus-Seminar on Surface Studies by Nonlinear Laser Spectroscopies, Kassel, Germany, May 30 to June 1, 1994 相似文献
17.
It is shown that the attraction of femtosecond solitons in fibres is possible. Soliton attraction is calculated numerically, taking into account the fifth-order non-linearity in the refractive index of the fibre for the varying initial conditions. The role of the non-linear and dispersion higher-order effects and self-frequency shift in soliton attraction is also considered. 相似文献
18.
19.
Cross-phase modulation instability in optical fibres with exponential saturable nonlinearity and high-order dispersion 下载免费PDF全文
Utilizing the linear-stability analysis, this paper
analytically investigates and calculates the condition and gain
spectra of cross-phase modulation instability in optical fibres in
the case of exponential saturable nonlinearity and high-order
dispersion. The results show that, the modulation instability
characteristics here are similar to those of conventional saturable
nonlinearity and Kerr nonlinearity. That is to say, when the
fourth-order dispersion has the same sign as that of the
second-order one, a new gain spectral region called the second one
which is far away from the zero point may appear. The existence of
the exponential saturable nonlinearity will make the spectral width
as well as the peak gain of every spectral region increase with the
input powers before decrease. Namely, for every spectral regime,
this may lead to a unique value of peak gain and spectral width for
two different input powers. In comparison with the case of
conventional saturable nonlinearity, however, when the other
parameters are the same, the variations of the spectral width and
the peak gain with the input powers will be faster in case of
exponential saturable nonlinearity. 相似文献
20.
A method is described for the measurement of material dispersion in the core of an optical fibre, over a wide wavelength range. The method is relatively insensitive to the pulse dispersion caused by group delay differences between modes in the fibre. It is found that the dispersion of phosphosilicate core material is no greater than that of fused silica and is independent of composition over the range measured. 相似文献