Modulation instabilities in two-core optical fibers

Previous studies of the modulation instability (MI) of continuous waves (CWs) in a two-core fiber (TCF) did not consider effects caused by co-propagation of the two polarized modes in a TCF that possesses birefringence, such as cross-phase modulation (XPM), polarization-mode dispersion (PMD), and polarization-dependent coupling (PDC) between the cores. This paper reports an analysis of these effects on the MI by considering a linear-birefringence TCF and a circular-birefringence TCF, which feature different XPM coefficients. The analysis focuses on the MI of the asymmetric CW states in the TCFs, which have no counterparts in single-core fibers. We find that, the asymmetric CW state exists when its total power exceeds a threshold (minimum) value, which is sensitive to the value of the XPM coefficient. We consider, in particular, a class of asymmetric CW states that admit analytical solutions. In the anomalous dispersion regime, without taking the PMD and PDC into account, the MI gain spectra of the birefringent TCF, if scaled by the threshold power, are almost identical to those of the zero-birefringence TCF. However, in the normal dispersion regime, the power-scaled MI gain spectra of the birefringent TCFs are distinctly different from their zero-birefringence counterparts, and the difference is particularly significant for the circular-birefringence TCF, which takes a larger XPM coefficient. On the other hand, the PMD and PDC only exert weak effects on the MI gain spectra. We also simulate the nonlinear evolution of the MI of the CW inputs in the TCFs and obtain a good agreement with the analytical solutions.

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“…(20). Equations (22) and (24) have been derived elsewhere by directly solving the system of two coupled equations [22].…”

Section: Zero-birefringence Tcf:  =mentioning

confidence: 99%

Modulation Instabilities in Birefringent Two-core Optical Fibers

Chiang

Malomed

et al. 2012

Asia Communications and Photonics Conference

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“…The phenomenon of periodic optical power transfer between the two cores along a TCF [19] is widely used in many practical fiber-optic devices. Various aspects of the MI in a TCF have been studied [20][21][22]. The MI characteristics of the symmetric and antisymmetric CW states in a TCF are qualitatively similar to those in a conventional single-core fiber [20].…”

Section: Introductionmentioning

confidence: 96%

“…On the other hand, the spontaneous symmetry breaking in linearly coupled systems gives rise to asymmetric CW states in a TCF [23], which makes its MI characteristics qualitatively different from those of a single-core fiber [21]. In particular, the dispersion (or wavelength dependence) of the coupling coefficient between the two cores can drastically modify the MI bands of the asymmetric states in both the anomalous and normal dispersion regimes [22].…”

Section: Introductionmentioning

confidence: 99%

Modulation instabilities in birefringent two-core optical fibres

Chiang

Malomed

et al. 2012

J. Phys. B: At. Mol. Opt. Phys.

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Previous studies of the modulation instability (MI) of continuous waves (CWs) in a two-core fibre (TCF) did not consider effects caused by co-propagation of the two polarized modes in a TCF that possesses birefringence, such as cross-phase modulation (XPM), polarization-mode dispersion (PMD) and polarization-dependent coupling (PDC) between the cores. This paper reports an analysis of these effects on the MI by considering a linear-birefringence TCF and a circular-birefringence TCF, which feature different XPM coefficients. The analysis focuses on the MI of the asymmetric CW states in the TCFs, which have no counterparts in single-core fibres. We find that the asymmetric CW state exists when its total power exceeds a threshold (minimum) value, which is sensitive to the value of the XPM coefficient. We consider, in particular, a class of asymmetric CW states that admit analytical solutions. In the anomalous dispersion regime, without taking the PMD and PDC into account, the MI gain spectra of the birefringent TCF, if scaled by the threshold power, are almost identical to those of the zero-birefringence TCF. However, in the normal dispersion regime, the power-scaled MI gain spectra of the birefringent TCFs are distinctly different from their zero-birefringence counterparts, and the difference is particularly significant for the circular-birefringence TCF, which takes a larger XPM coefficient. On the other hand, the PMD and PDC only exert weak effects on the MI gain spectra. We also simulate the nonlinear evolution of the MI of the CW inputs in the TCFs and obtain good agreement with the analytical solutions.

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“…Among different types of fiber lasers, dual-core ring lasers have been receiving a widespread interest owing to their numerous applications in photonics [13][14][15][16][17][18][19]. Nonlinear directional couplers (NLDC) are one of important components of integrated optical devices and they deliver quite a few lightwave applications including switching (bright and dark) [20][21][22][23][24][25][26][27], logical operations [28,29], ultra-short pulse generation through modulational instability [30][31][32][33][34][35], and amplifiers [36,37]. In particular, Winful and Walton have proven that the asymmetric dual core fibers can act as a passive mode-locking fiber laser provided one of the dual-cores must be doped with rare earth-elements like erbium while the other core must be a passive one [3].…”

Section: Introductionmentioning

confidence: 99%

Non-Lagrangian approach for coupled complex Ginzburg-Landau systems with higher order-dispersion

Djob

Kenfact-Jiotsa

Govindarajan

2020

Chaos, Solitons & Fractals

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It is known that after a particular distance of evolution in fiber lasers, two (input) asymmetric soliton like pulses emerge as two (output) symmetric pulses having same and constant energy. We report such a compensation technique in dispersion managed fiber lasers by means of a semi-analytical method known as collective variable approach (CVA) with including third-order dispersion (TOD). The minimum length of fiber laser, at which the output symmetric pulses are obtained from the input asymmetric ones, is calculated for each and every pulse parameters numerically by employing Runge-Kutta fourth order method. The impacts of intercore linear coupling, asymmetric nature of initial parameters and TOD on the evolution of pulse parameters and on the minimum length are also investigated. It is found that strong intercore linear coupling and asymmetric nature of input pulse parameters result in the reduction of fiber laser length. Also, the role of TOD tends to increase the width of the pulses as well as their energies. Besides, chaotic patterns and bifurcation points on the minimum length of the fiber owing to the impact of TOD are also reported in a nutshell.

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Modulation instabilities in two-core optical fibers

Cited by 75 publications

References 44 publications

Modulation Instabilities in Birefringent Two-core Optical Fibers

Modulation Instabilities in Birefringent Two-core Optical Fibers

Modulation instabilities in birefringent two-core optical fibres

Non-Lagrangian approach for coupled complex Ginzburg-Landau systems with higher order-dispersion

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