Related Experiment Video
Updated: Jun 5, 2026
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Nonlinear coupling in triangular triple-core photonic crystal fibers
Peng Li1, Jianlin Zhao, Xiaojuan Zhang
1Shaanxi Key Laboratory of Optical Information Technology, The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Science, Northwestern Polytechnical University, Xi'an, China.
Optics Express
|January 4, 2011
Summary
Triangular triple-core photonic crystal fibers (TTC-PCFs) offer superior power selectivity and sharper optical switching compared to dual-core designs. Asymmetric TTC-PCFs enable efficient power transfer for optical switching and pulse shaping applications.
Area of Science:
- Photonics
- Optical Fiber Technology
- Nonlinear Optics
Background:
- Photonic crystal fibers (PCFs) offer unique light-guiding properties.
- Dual-core PCFs have been explored for optical switching, but limitations exist.
- Nonlinear coupling in multi-core PCFs requires further investigation.
Purpose of the Study:
- To numerically analyze the nonlinear coupling characteristics of triangular triple-core photonic crystal fibers (TTC-PCFs).
- To compare the performance of TTC-PCFs with traditional dual-core PCFs.
- To explore the potential of TTC-PCFs for advanced optical applications.
Main Methods:
- Coupled mode theory was employed for numerical analysis.
- Simulations focused on nonlinear coupling in TTC-PCFs.
- Parameter variations (structure, length) were investigated.
Main Results:
- TTC-PCFs demonstrate superior power selectivity compared to dual-core PCFs.
- Asymmetric TTC-PCFs enable sharper optical switching and coupling bands at lower critical power.
- Optimized TTC-PCFs achieve over 90% input power transfer with a flat coupling band.
Conclusions:
- TTC-PCFs present enhanced nonlinear coupling characteristics.
- Asymmetric TTC-PCFs are promising for efficient optical switching.
- These findings open possibilities for pulse shaping and pulse compressing applications.
Related Concept Videos
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:27¹H NMR: Long-Range Coupling
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
01:17Spin–Spin Coupling: One-Bond Coupling
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
01:27Symmetry Elements in a Crystal
Crystal symmetry operations are isometric transformations that map objects onto indistinguishable copies while preserving distances, angles, and volumes. The simplest symmetry operation is translation, which shifts the entire infinite crystal lattice parallelly by a translation vector.Crystallographic rotations involve rotations by an angle of 2π/n around an axis without changing the positions of points on the axis. It is called the rotational axis of the symmetry, denoted by n. The combination...