scholarly journals Simulation of Pulse Propagation in Optical Fibers

2016 ◽  
Vol 64 ◽  
pp. 159-170
Author(s):  
P.C.T. Munaweera ◽  
K.A.I.L. Wijewardena Gamalath
Keyword(s):  
Optical Fibers ◽  
Pulse Propagation ◽  
Group Velocity Dispersion ◽  
Nonlinear Coefficient ◽  
Input Pulse ◽  
Fourier Method ◽  
Nonlinear Effects ◽  
Input Power ◽  
Light Pulses ◽  
Order Dispersion

A theoretical model was developed for light pulses propagating in optical fibers by considering the nonlinear effects, the self-phase modulation and group velocity dispersion effects. The split step Fourier method was used to generate soliton pulses in a fiber composed of a glass core surrounded by a cladding layer. Gaussian and hyperbolic secant input pulses were used for the simulation. By varying the initial chirp, input power and nonlinear coefficient for an input Gaussian pulse at wavelength of λ =1.55μm with initial pulse width 125ps for second order dispersion β2=−20 ps2km-1, nonlinear parameter γ=3W-1kg-1and initial chirp C=−0.25 two near soliton pulses were generated for input powers P = 0.54mW and P = 0.64mW and a perfect soliton for the hyperbolic secant input pulse.

scholarly journals Bandwidth-limited few-cycle pulses by nonlinear compression in a dispersion-alternating fiber

2020 ◽  
Vol 126 (11) ◽  
Author(s):  
Niklas M. Lüpken ◽  
Carsten Fallnich
Keyword(s):  
Phase Modulation ◽  
Pulse Compression ◽  
Group Velocity Dispersion ◽  
Input Pulse ◽  
Nonlinear Compression ◽  
The Impact ◽  
Higher Order Dispersion ◽  
Normally Dispersive Fiber ◽  
Order Dispersion ◽  
Good Agreement

AbstractWe demonstrate an improved concept for nearly bandwidth-limited nonlinear pulse compression down to the few-cycle regime in a fiber chain with alternating sign of dispersion. Whereas the normally dispersive fiber segments generate bandwidth via self-phase modulation, the anomalously dispersive fiber segments recompress the broadened spectral bandwidth by an appropriate amount of group velocity dispersion. Nonlinear pulse compression from 80 fs input pulses to nearly bandwidth-limited 25 fs pulses at 1560 nm was achieved, resulting in a pulse compression factor of 3.2. The use of a specific dispersion-compensating fiber eliminated the impact of higher-order dispersion, such that a high spectral coherence was ensured. We show that nonlinear Schrödinger equation simulations were in good agreement with the experimental results and investigated the transfer of input fluctuations to the output. The concept is transferable to longer input pulse durations, resulting in compression factors of 83 for 10 ps input pulses.

Random distributed feedback fiber lasers: Impact of third-order dispersion

2019 ◽  
Vol 28 (04) ◽  
pp. 1950035
Author(s):  
Fatemeh Mazarei ◽  
Gholamreza Honarasa ◽  
Hassan Pakarzadeh ◽  
Iraj Sadegh Amiri
Keyword(s):  
Output Power ◽  
Nonlinear Coefficient ◽  
Input Power ◽  
Distributed Feedback ◽  
Third Order ◽  
Third Order Dispersion ◽  
Stokes Waves ◽  
Output Characteristics ◽  
Power Evolution ◽  
Order Dispersion

In this paper, one of the most modern random lasers known as random distributed feedback fiber laser is investigated when the third-order dispersion (TOD) is taken into account. The laser characteristics are simulated based on the nonlinear Schrödinger equations (NLSEs) where the power evolution of three interacting waves: the pump, the forward and the backward Stokes waves, are investigated as they propagate down the fiber. The results show that due to TOD, the output characteristics of the laser are changed and particularly, the output power becomes asymmetrical. Moreover, the impacts of fiber nonlinear coefficient and input power on the output power and the output spectrum are studied.

scholarly journals Application of the G'/G Expansion Method in Ultrashort Pulses in Nonlinear Optical Fibers

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Jiang Xing-Fang ◽  
Wang Jun ◽  
Wei Jian-Ping ◽  
Hua Ping
Keyword(s):  
Optical Fibers ◽  
Wavelength Division Multiplexing ◽  
Nonlinear Optical ◽  
Group Velocity Dispersion ◽  
Ultrashort Pulses ◽  
Expansion Method ◽  
Input Power ◽  
Trigonometric Function ◽  
High Order ◽  
Wavelength Division

With the increasing input power in optical fibers, the dispersion problem is becoming a severe restriction on wavelength division multiplexing (WDM). With the aid of solitons, in which the shape and speed can remain constant during propagation, it is expected that the transmission of nonlinear ultrashort pulses in optical fibers can effectively control the dispersion. The propagation of a nonlinear ultrashort laser pulse in an optical fiber, which fits the high-order nonlinear Schrödinger equation (NLSE), has been solved using the G'/G expansion method. Group velocity dispersion, self-phase modulation, the fourth-order dispersion, and the fifth-order nonlinearity of the high-order NLSE were taken into consideration. A series of solutions has been obtained such as the solitary wave solutions of kink, inverse kink, the tangent trigonometric function, and the cotangent trigonometric function. The results have shown that the G'/G expansion method is an effective way to obtain the exact solutions for the high-order NLSE, and it provides a theoretical basis for the transmission of ultrashort pulses in nonlinear optical fibers.

Design and Analysis of a Dispersion-engineered and Highly Nonlinear Rib Waveguide for Generation of Broadband Supercontinuum Spectra

Frequenz ◽  
2020 ◽  
Vol 74 (3-4) ◽  
pp. 153-161
Author(s):  
Mohammad Reza Alizadeh ◽  
Mahmood Seifouri
Keyword(s):  
Integrated Circuits ◽  
Dispersion Curve ◽  
Nonlinear Coefficient ◽  
Input Pulse ◽  
Input Power ◽  
Optical Integrated Circuits ◽  
Highly Nonlinear ◽  
Suitable Structure ◽  
Large Width ◽  
Mode Area

AbstractIn this paper, a waveguide consisting of a core of As2Se3 chalcogenide glass and the upper and lower claddings of MgF2 with two zero-dispersion wavelengths (ZDW) has been proposed. By optimization of the dimensions of the core and the claddings, their effects on the dispersion curve have been investigated and a suitable structure with a flat dispersion curve, an effective mode area of ​​1.6 μm2 in a pump wavelength of 2.8 μm, and hence, a nonlinear coefficient greater than 34 w−1 m−1 has been obtained. A broadband supercontinuum in a wavelength range of 1.5 μm to 15 μm has been generated by applying an input pulse with duration of 100 fs and a maximum power of 2 kw to this waveguide. Due to the large width of the supercontinuum generated (SCG), the short length of the waveguide (maximum 5 mm), and a low input power, this structure is suitable for use in optical integrated circuits and its various applications.

Nonlinear pulse reshaping in a typically designed silicon on insulator waveguide and its application to generate high repetition rate pulse train

2021 ◽  
Author(s):  
Somen Adhikary ◽  
Mousumi Basu
Keyword(s):  
Optical Fibers ◽  
Repetition Rate ◽  
High Frequency ◽  
Pulse Train ◽  
Group Velocity Dispersion ◽  
Nonlinear Coefficient ◽  
Optical Signal ◽  
High Repetition Rate ◽  
Silicon On Insulator ◽  
Pulse Generators

Abstract A Silicon on Insulator (SOI) planar waveguide is designed here possessing a small group velocity dispersion (β2) ∼ 2.212 (ps2/m) with quite high nonlinear coefficient (γ) of ∼ 360.57 (W.m)-1. The so designed waveguide is capable of reshaping a Super-Gaussian input optical pulse into parabolic pulse (PP), without any use of external gain. The same waveguide with relatively longer length is also able to generate triangular pulse (TP) by using positive chirp at the input. In both cases PP and TP are created at much shorter optimum length (Lopt) of few mm, when compared to previously reported works on normal dispersion optical fibers. The interaction of a pulse pair inside such a SOI waveguide is investigated also for the first time as per our knowledge to generate of a high frequency (~ 4.8 THz) pulse train, while lower repetition rate (~180 GHz) pulses are used at the input. This study as a whole enables one to have potential device applications in the domain of tunable high frequency (THz) pulse generators, optical signal processing and many more.

Simultaneous measurement of anomalous group-velocity dispersion and nonlinear coefficient in optical fibers using soliton-effect compression

2007 ◽  
Vol 278 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Thanh Nam Nguyen ◽  
Thierry Chartier ◽  
Monique Thual ◽  
Pascal Besnard ◽  
Laurent Provino ◽  
...  
Keyword(s):  
Group Velocity ◽  
Optical Fibers ◽  
Simultaneous Measurement ◽  
Velocity Dispersion ◽  
Group Velocity Dispersion ◽  
Nonlinear Coefficient

scholarly journals The local wave phenomenon in the quintic nonlinear Schrödinger equation by numerical methods

2021 ◽  
Author(s):  
Yaning Tang ◽  
Zaijun Liang ◽  
Wenxian Xie
Keyword(s):  
Optical Fibers ◽  
Analytical Solutions ◽  
Initial Conditions ◽  
Fourier Method ◽  
Nls Equation ◽  
Nonlinear Schrödinger ◽  
Light Pulses ◽  
Propagation Of Light ◽  
Wide Range ◽  
Local Wave

Abstract The nonlinear Schrodinger hierarchy has a wide range of applications in modeling the propagation of light pulses in optical fibers. In this paper, we focus on the integrable nonlinear Schrodinger (NLS) equation with quintic terms, which play a prominent role when the pulse duration is very short. First, we investigate the spectral signatures of the spatial Lax pair with distinct analytical solutions and their periodized wavetrains by Fourier oscillatory method. Then, we numerically simulate the wave evolution of the quintic NLS equation from different initial conditions through the symmetrical split-step Fourier method. We find many localized high-peak structures whose profiles are very similar to the analytical solutions, and we analyze the formation of rouge waves (RWs) in different cases. These results may be helpful to understand the excitation of nonlinear waves in some nonlinear fields, such as optical fibers, oceanography and so on.

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