Nonlinear anti-directional couplers with gain and loss

Govindarajan, A.; Malomed, Boris A.; Lakshmanan, M.

doi:10.1364/ol.44.004650

Cited by 18 publications

(15 citation statements)

References 44 publications

(51 reference statements)

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“…Although the ADC resembles conventional gain-loss dimers, the contrast between its arms gives rise to light-guiding characteristics similar to those of distributed feedback structures, such as Bragg gratings, due to opposite signs of the Poynting vector ( − → S in Fig. 1) and phase velocities in the parallel-coupled NRI and PRI channels [5,[12][13][14]. Accordingly, ADC models exhibit both forward and backward propagation and optical bi- and multi-stabilities, in addition to the formation of nonstationary localized modes and discrete solitons in waveguide arrays [15].…”

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confidence: 99%

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Tunable nonlinear spectra of anti-directional couplers

2020

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We produce transmission and reflection spectra of the anti-directional coupler (ADC) composed of linearlycoupled positive-and negative-refractive-index arms, with intrinsic Kerr nonlinearity. Both reflection and transmission feature two highly amplified peaks at two distinct wavelengths in a certain range of values of the gain, making it possible to design a wavelengthselective mode-amplification system. We also predict that a blend of gain and loss in suitable proportions can robustly enhance reflection spectra which are detrimentally affected by the attenuation, in addition to causing red and blue shifts owing to the Kerr effect. In particular, ADC with equal gain and loss coefficients, is considered in necessary detail.

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“…We here focus on this subject, with the intention to analyze the effects of the gain and loss strengths in the coupled channels on the nonlinear spectra, and propose feasible applications to all-optical signal-processing networks. channels, are written as [12,14] +i…”

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confidence: 99%

Tunable nonlinear spectra of anti-directional couplers

2020

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“…Presently, the notion of P T -symmetry is reckoned as one of the research areas to be subjected to an intense investigation by the scientific community (See Refs. [26][27][28][29][30][31][32][33][34][35][36] and therein). This notion would have remained as an unrealistic subject in real physical settings forever if not for the fact that the fundamental postulates of P T -symmetry can be translated from quantum mechanics to optics [26,37,38].…”

Section: Introductionmentioning

confidence: 99%

Low-power optical bistability in $\mathcal{PT}$-symmetric chirped Bragg gratings with four-wave mixing

Sudhakar,

Raja,

Govindarajan

et al. 2022

Preprint

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The central theme of this article is the analysis of the usefulness of introducing four-wave mixing or modulation of Kerr nonlinearity in a nonuniform grating structure with gain and loss. To do so, we propose an inhomogeneous system in which the nonlinearity of the P T -symmetric grating is modulated. It is proven that the proposed scheme can be fruitful only if the nonlinearity and its associated modulation terms are assumed to be self-defocusing ones. In order to cut down the intensity required for the steering, the sign of chirping is taken to be negative and the wavelength of operating light is considered to be higher than the Bragg wavelength. Alongside these settings, launching the light from the rear end of the device dramatically reduces the critical intensity to a value of 0.015 (approximately) which must be the lowest switching intensity ever reported in the context of nonlinear P T -symmetric gratings. The ramplike stable states in the broken P T -symmetric regime prevail even in the company of modulation in the nonlinearity index for both of the light incident directions.

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“…Supersymmetry has been found very useful in phase-matched mode selection, removal of undesired modes and other phase-sensitive applications [23]. It plays a crucial role in designing PT inspired optical couplers [24][25][26]. Both these symmetries are characterized by unbroken and broken phases, having different physical properties in optical systems.…”

Section: Introductionmentioning

confidence: 99%

PT-symmetry and supersymmetry: interconnection of broken and unbroken phases

et al. 2021

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The broken and unbroken phases of P T and supersymmetry in optical systems are explored for a complex refractive index profile in the form of a Scarf potential, under the framework of supersymmetric quantum mechanics. The transition from unbroken to the broken phases of P T -symmetry, with the merger of eigenfunctions near the exceptional point is found to arise from two distinct realizations of the potential, originating from the underlying supersymmetry. Interestingly, in P T -symmetric phase, spontaneous breaking of supersymmetry occurs in a parametric domain, possessing non-trivial shape invariances, under reparametrization to yield the corresponding energy spectra. One also observes a parametric bifurcation behaviour in this domain. Unlike the real Scraf potential, in P T -symmetric phase, a connection between complex isospecrtal superpotentials and modified Korteweg-de Vries equation occurs, only with certain restrictive parametric conditions. In the broken P T -symmetry phase, supersymmetry is found to be intact in the entire parameter domain yielding the complex energy spectra, with zero-width resonance occurring at integral values of a potential parameter.

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Nonlinear anti-directional couplers with gain and loss

Cited by 18 publications

References 44 publications

Tunable nonlinear spectra of anti-directional couplers

Tunable nonlinear spectra of anti-directional couplers

Low-power optical bistability in $\mathcal{PT}$-symmetric chirped Bragg gratings with four-wave mixing

PT-symmetry and supersymmetry: interconnection of broken and unbroken phases

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