Nearly pedestal-free optical pulse compression using self-similar chirped optical solitons near the photonic bandgap (PBG) structure of nonlinear fiber Bragg gratings (NFBGs) with exponentially decreasing dispersion is investigated using the generalized nonlinear coupled-mode equations (NLCMEs). The full dispersion characteristics and the effect of PBG are included. We find that the ratio of the frequency detune of the pulse's center frequency from the Bragg frequency of the NFBG to coupling coefficient of the NFBG is an important design parameter of the NFBG optical pulse compressor. We carried out a comprehensive study on the effect of the ratio of frequency detune to coupling coefficient, grating length, initial chirp, initial dispersion, and initial pulsewidth on the self-similar optical pulse compression. We also studied the compression of both the hyperbolic secant and Gaussian-shaped pulses and the effect of variation in the initial pulsewidth on the optical pulse compression. © 2006 IEEE.

Senthilnathan K

Department of Physics

School of Advanced Sciences

Vellore Campus

Li Q

Wai P.K.A

Nakkeeran K.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Modeling Self-Similar Optical Pulse Compression in Nonlinear Fiber Bragg Grating Using Coupled-Mode Equations

Journal of Lightwave Technology

We propose a simple scheme to generate high-energy ultrashort pulses by combination and compression of multiple input pulses which share the same chirp profile. First, the multiple raised-cosine pulses in the input pulse train are modulated by a phase modulator, in which each modulation cycle covers two, three, four, or five pulses. Then, the modulated pulses are launched into a nonlinear fiber with the exponentially decreasing dispersion. We find that these pulses initially coalesce into a single pulse whose pulse profile is nearly hyperbolic secant, which then undergoes self-similar compression. Thus in the proposed method, first the combination of the multiple optical pulses occurs and then self-similar compression takes over. Besides, we also report the generation of ultrashort pulses by combination and compression of multiple hyperbolic secant pulses with the same chirp. The numerical results reveal that the resulting ultrashort pulse possesses a large portion of the input pulses for both raised-cosine and hyperbolic secant pulses. However, the compression factor and energy ratio are relatively higher for the hyperbolic secant pulses when compared with the raised-cosine pulses. © 1965-2012 IEEE.

Fulltext

IEEE Journal of Quantum Electronics

Combination and Compression of Multiple Optical Pulses in Nonlinear Fibers with the Exponentially Decreasing Dispersion

We consider a light wave propagation in tapered photonic crystal fibres (PCFs) wherein the wave propagation is described by the variable coefficient nonlinear Schrödinger equation. We solve it directly by means of the theta function identities and Hirota bilinear method in order to obtain the exact periodic waves of sn, cn and dn types. These chirped period waves demand exponential variations in both dispersion and nonlinearity. Besides, we analytically demonstrate the generation of a train of ultrashort pulses using the periodic waves by exploiting the exponentially varying optical properties of the tapered PCFs. As a special case, we discuss the chirped solitary pulses under long wave limit of these periodic waves. In addition, we derive these types of periodic waves using the self-similar analysis and compare the results. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

Journal of Modern Optics

Generation of a train of ultrashort pulses using periodic waves in tapered photonic crystal fibres

We consider the evolution of nonlinear optical pulses in inhomogeneous optical media wherein the pulse propagation is governed by the nonlinear Schrödinger equation with varying dispersion. We adopt the Painlevé analysis in order to obtain the condition for the soliton pulse propagation. We find that there exist two dispersion profiles satisfying this criterion, namely, the constant dispersion and exponentially dispersion decreasing profiles. In the exponentially varying dispersion media, we explain the existence and the formation of chirped optical soliton through the equation for the chirp parameter that results from variational analysis. For further elucidation, we provide the phase-plane diagram in terms of the normalized chirp and intensity (peak power), which explains the physical mechanism of linearly chirped soliton pulse compression in the exponentially dispersion decreasing media. In addition, we discuss the generation of exact chirped higher order solitons using the Bäcklund transformation method. As a special case, we find an oscillatory two-soliton breather pulse, which, at decreasing intervals, evolves into a familiar hyperbolic secant shape whose amplitude is twice that of a fundamental soliton. We highlight on the point that the crux of this work in realizing a compact pulse compressor could possibly result in a myriad of applications in modern optical fiber communications systems. © 2011 Elsevier B.V. All rights reserved.

Optics Communications

Pedestal free pulse compression of chirped optical solitons

Journal of the Optical Society of America B

Nearly chirp- and pedestal-free pulse compression in nonlinear fiber Bragg gratings

Physical Review Letters

Nonlinearity Management in Optics: Experiment, Theory, and Simulation

Applied Optics

Picosecond soliton transmission by use of concatenated gain-distributed nonlinear amplifying fiber loop mirrors

Physical Review E

Exact solutions of the generalized nonlinear Schrödinger equation with distributed coefficients

Optics Express

Intermediate asymptotic evolution and photonic bandgap fiber compression of optical similaritons around 1550 nm

Journal	Data powered by TypesetJournal of Lightwave Technology
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers (IEEE)
ISSN	0733-8724
Open Access	No