Samudra Roy
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View article: Radiation families emitted by a discrete soliton in parity-time-symmetric waveguide arrays
Radiation families emitted by a discrete soliton in parity-time-symmetric waveguide arrays Open
We investigate the dynamics of a spatial discrete soliton and the radiation families emitted by it inside a parity-time ($\mathcal{PT}$)-symmetric waveguide array with alternate gain-loss channels. A strong spatial soliton that evolves ins…
View article: Beam propagation in an active nonlinear graded-index fiber
Beam propagation in an active nonlinear graded-index fiber Open
A theoretical model is developed by exploiting the variational technique to investigate the evolution of an optical beam inside an optically pumped graded-index fiber amplifier. The variational analysis is a semi-analytical method that pro…
View article: Spatial beam dynamics in graded-index multimode fibers under Raman amplification:a variational approach
Spatial beam dynamics in graded-index multimode fibers under Raman amplification:a variational approach Open
We investigate the spatial beam dynamics inside a multimode graded-index fiber under Raman amplification by adopting a semi-analytical variational approach. The variational analysis provides us with four coupled ordinary differential equat…
View article: Collision dynamics of discrete soliton in uniform waveguide arrays
Collision dynamics of discrete soliton in uniform waveguide arrays Open
We investigate the collision dynamics of discrete soliton (DS) pair in a realistic semi-infinite nonlinear waveguide array (WA) in the context of \textit{diffractive resonant radiation} (DifRR). Depending on the initial amplitude ($A_0$) a…
View article: Spatial dissipative solitons in graphene-based active random metamaterials
Spatial dissipative solitons in graphene-based active random metamaterials Open
We investigate dissipative nonlinear dynamics in graphene-based active metamaterials composed of randomly dispersed graphene nano-flakes embedded within an externally pumped gain medium. We observe that graphene saturable nonlinearity prod…
View article: Free-carrier-induced nonlinear dynamics in hybrid graphene-based photonic waveguides
Free-carrier-induced nonlinear dynamics in hybrid graphene-based photonic waveguides Open
We develop from first principles a theoretical model for infrared pulse propagation in graphene-covered hybrid waveguides. We model electron dynamics in graphene by Bloch equations, enabling the derivation of the nonlinear conductivity and…
View article: Intracavity field dynamics near avoided mode crossing in a concentric silicon-nitride ring resonator
Intracavity field dynamics near avoided mode crossing in a concentric silicon-nitride ring resonator Open
Understanding the intra-cavity field dynamics in passive microresonator systems has already been intriguing. It becomes fascinating when the system is complex, such as a concentric dual microring resonator that exhibit avoided mode crossin…
View article: Dynamics and selective temporal focusing of a time truncated Airy pulse in varying dispersive media
Dynamics and selective temporal focusing of a time truncated Airy pulse in varying dispersive media Open
We theoretically and numerically investigate the dynamics of a time truncated finite energy Airy pulse (FEAP) under longitudinally varying group velocity dispersion (GVD), which significantly influences the Airy dynamics. Realistic wavegui…
View article: Dynamic diffractive resonant radiation in a linearly chirped nonlinear waveguide array
Dynamic diffractive resonant radiation in a linearly chirped nonlinear waveguide array Open
We theoretically and numerically investigate the evolution of discrete\nsoliton in a 1D linearly chirped nonlinear waveguide array (WA). The discrete\nsoliton is self-accelerated inside the transversely chirped WA and emits a\n\\textit{dyn…
View article: Trajectory manipulation of an Airy pulse near zero-dispersion wavelength under a free-carrier-generated linear potential
Trajectory manipulation of an Airy pulse near zero-dispersion wavelength under a free-carrier-generated linear potential Open
We investigate the dynamics of an Airy pulse that experiences free carrier generated optical linear potential in the vicinity of zero group velocity dispersion (GVD) wavelength inside a Si based waveguide. The optically induced potential c…
View article: Stability and variational analysis of cavity solitons under various perturbations
Stability and variational analysis of cavity solitons under various perturbations Open
We theoretically investigate the dynamics and stability of a temporal cavity soliton (CS) excited inside a silicon-based microresonator that exhibits free-carrier generation as a result of two-photon absorption (TPA). The optical propagati…
View article: Variational approach to study soliton dynamics in a passive fiber loop resonator with coherently driven phase-modulated external field
Variational approach to study soliton dynamics in a passive fiber loop resonator with coherently driven phase-modulated external field Open
We report a detailed semianalytical treatment to investigate the dynamics of a single cavity soliton (CS) and two copropagating CSs separately in a Kerr mediated passive optical fiber resonator which is driven by a phase-modulated pump. Th…
View article: Heat-induced soliton self-frequency redshift in the ultrafast nonlinear dynamics of active plasmonic waveguides
Heat-induced soliton self-frequency redshift in the ultrafast nonlinear dynamics of active plasmonic waveguides Open
We investigate the ultrafast nonlinear dynamics of light emitted in an active\nplasmonic waveguide composed of a thin film of gold sandwiched by two silicon\nlayers immersed in externally pumped Al$_2$O$_3$:Er$^{3+}$. We model optical\npro…
View article: A complete theoretical analysis of cavity solitons under various perturbations
A complete theoretical analysis of cavity solitons under various perturbations Open
We theoretically investigate the dynamics and stability of a temporal cavity soliton (CS) excited inside a silicon-based microresonator that exhibits free-carrier generation as a results of two-photon absorption (TPA). The optical propagat…
View article: Dissipative solitons in self-defocussing nonlinear media: The curious case of zero-nonlinearity point
Dissipative solitons in self-defocussing nonlinear media: The curious case of zero-nonlinearity point Open
We theoretically model a dissipative system which exhibits self-defocussing nonlinearity and numerically study the dynamics of optical dissipative solitons (DSs) whose evolution is governed by a complex Ginzburg-Landau equation (GLE). We s…
View article: Collision-mediated radiation due to Airy-soliton interaction in a nonlinear Kerr medium
Collision-mediated radiation due to Airy-soliton interaction in a nonlinear Kerr medium Open
We study the interaction of a co-propagating finite energy Airy pulse and a\nsoliton in a Kerr medium under third order dispersion. It is observed that a\nstrong radiation appears when selfaccelerating Airy pulse collides with a\ndelayed s…
View article: Dissipative soliton mediated radiations in active silicon-based waveguides
Dissipative soliton mediated radiations in active silicon-based waveguides Open
The Ginzburg-Landau (GL) equation is in general not integrable by the inverse scattering method and support solitary-wave solution, called dissipative soliton (DS). We numerically demonstrate that, a DS can radiate dispersive waves (DWs) i…
View article: Dynamics of self-healing Airy pulse under phase modulation: Few interesting aspects
Dynamics of self-healing Airy pulse under phase modulation: Few interesting aspects Open
We study the interesting dynamics of Airy pulse under phase modulation in pure linear regime where third order dispersion is the only perturbation experienced by the pulse. We propose the geometry of a simple Si-based wave guide which can …
View article: Dynamics of Airy pulse under phase modulation: Few interesting aspects
Dynamics of Airy pulse under phase modulation: Few interesting aspects Open
In this work we have tried to study the interesting dynamics of Airy pulse under phase modulation. We investigate the role of linear, quadratic and cubic phase modulation on Airy pulse dynamics in pure linear regime. As a specific example,…
View article: Perturbed dissipative solitons: A variational approach
Perturbed dissipative solitons: A variational approach Open
We adopt a variational technique to study the dynamics of perturbed\ndissipative solitons, whose evolution is governed by a Ginzburg--Landau\nequation (GLE). As a specific example of such solitons, we consider a\nsilicon-based active waveg…
View article: Effect of two-photon absorption on cavity soliton: stability and perturbation analysis
Effect of two-photon absorption on cavity soliton: stability and perturbation analysis Open
We study the stability criteria and propagation dynamics of cavity soliton under two photon absorption by solving Lugiato–Lefever equation numerically. A semi-analytical variational method is further adopted to explain the complete dynamic…
View article: Implications of a zero-nonlinearity wavelength in photonic crystal fibers doped with silver nanoparticles
Implications of a zero-nonlinearity wavelength in photonic crystal fibers doped with silver nanoparticles Open
Photonic crystal fibers doped with silver nanoparticles exhibit the Kerr nonlinearity that can be positive or negative depending on wavelength and vanishes at a specific wavelength. We study numerically how the simultaneous presence of a z…