Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers
We investigate modulational instability (MI) in asymmetric dual-core nonlinear directional couplers incorporating the effects of the differences in effective mode areas and group velocity dispersions, as well as phase- and group-velocity mismatches. Using coupled-mode equations for this system, we i...
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MDPI AG
2017-06-01
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| Series: | Applied Sciences |
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| Online Access: | http://www.mdpi.com/2076-3417/7/7/645 |
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| author | Arjunan Govindarajan Boris A. Malomed Arumugam Mahalingam Ambikapathy Uthayakumar |
| author_facet | Arjunan Govindarajan Boris A. Malomed Arumugam Mahalingam Ambikapathy Uthayakumar |
| author_sort | Arjunan Govindarajan |
| collection | DOAJ |
| description | We investigate modulational instability (MI) in asymmetric dual-core nonlinear directional couplers incorporating the effects of the differences in effective mode areas and group velocity dispersions, as well as phase- and group-velocity mismatches. Using coupled-mode equations for this system, we identify MI conditions from the linearization with respect to small perturbations. First, we compare the MI spectra of the asymmetric system and its symmetric counterpart in the case of the anomalous group-velocity dispersion (GVD). In particular, it is demonstrated that the increase of the inter-core linear-coupling coefficient leads to a reduction of the MI gain spectrum in the asymmetric coupler. The analysis is extended for the asymmetric system in the normal-GVD regime, where the coupling induces and controls the MI, as well as for the system with opposite GVD signs in the two cores. Following the analytical consideration of the MI, numerical simulations are carried out to explore nonlinear development of the MI, revealing the generation of periodic chains of localized peaks with growing amplitudes, which may transform into arrays of solitons. |
| first_indexed | 2024-12-21T17:39:45Z |
| format | Article |
| id | doaj.art-ecbf15ae5bf549858f4a24788d37e616 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-12-21T17:39:45Z |
| publishDate | 2017-06-01 |
| publisher | MDPI AG |
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| series | Applied Sciences |
| spelling | doaj.art-ecbf15ae5bf549858f4a24788d37e6162022-12-21T18:55:39ZengMDPI AGApplied Sciences2076-34172017-06-017764510.3390/app7070645app7070645Modulational Instability in Linearly Coupled Asymmetric Dual-Core FibersArjunan Govindarajan0Boris A. Malomed1Arumugam Mahalingam2Ambikapathy Uthayakumar3Department of Physics, Presidency College, Chennai 600 005, Tamilnadu, IndiaDepartment of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, IsraelDepartment of Physics, Anna University, Chennai 600 025, Tamilnadu, IndiaDepartment of Physics, Presidency College, Chennai 600 005, Tamilnadu, IndiaWe investigate modulational instability (MI) in asymmetric dual-core nonlinear directional couplers incorporating the effects of the differences in effective mode areas and group velocity dispersions, as well as phase- and group-velocity mismatches. Using coupled-mode equations for this system, we identify MI conditions from the linearization with respect to small perturbations. First, we compare the MI spectra of the asymmetric system and its symmetric counterpart in the case of the anomalous group-velocity dispersion (GVD). In particular, it is demonstrated that the increase of the inter-core linear-coupling coefficient leads to a reduction of the MI gain spectrum in the asymmetric coupler. The analysis is extended for the asymmetric system in the normal-GVD regime, where the coupling induces and controls the MI, as well as for the system with opposite GVD signs in the two cores. Following the analytical consideration of the MI, numerical simulations are carried out to explore nonlinear development of the MI, revealing the generation of periodic chains of localized peaks with growing amplitudes, which may transform into arrays of solitons.http://www.mdpi.com/2076-3417/7/7/645modulational instabilityasymmetric nonlinear fiber couplerslinear stability approachcoupled nonlinear Schrödinger equations |
| spellingShingle | Arjunan Govindarajan Boris A. Malomed Arumugam Mahalingam Ambikapathy Uthayakumar Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers Applied Sciences modulational instability asymmetric nonlinear fiber couplers linear stability approach coupled nonlinear Schrödinger equations |
| title | Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers |
| title_full | Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers |
| title_fullStr | Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers |
| title_full_unstemmed | Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers |
| title_short | Modulational Instability in Linearly Coupled Asymmetric Dual-Core Fibers |
| title_sort | modulational instability in linearly coupled asymmetric dual core fibers |
| topic | modulational instability asymmetric nonlinear fiber couplers linear stability approach coupled nonlinear Schrödinger equations |
| url | http://www.mdpi.com/2076-3417/7/7/645 |
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