Related Experiment Video
Updated: Jul 16, 2026
08:06
Design and Fabrication of an Optical Fiber Made of Water
Published on: November 8, 2018
Wavelength-selective core-to-jacket coupling in optical fiber
Gary A Miller1, Charles G Askins, Thierry Taunay
1Optical Sciences Division, Naval Research Laboratory, Washington, DC 20375, USA. gray.miller@nrl.navy.mil
Optics Letters
|March 7, 2007
Summary
Mode coupling between optical fiber core and plastic jacket modes was observed. This phenomenon, predictable with coupled-mode theory, may enable new environmental sensing applications.
Area of Science:
- Optics
- Materials Science
- Photonics
Background:
- Optical fibers typically guide light within a core, with the cladding and jacket acting as passive layers.
- Mode coupling, the transfer of energy between different light modes, is generally minimized in standard fiber designs.
- Understanding interactions between the fiber core and surrounding materials is crucial for advanced fiber applications.
Purpose of the Study:
- To investigate and characterize mode coupling between the fundamental core mode and higher-order modes in the plastic jacketing of an optical fiber.
- To determine the feasibility of predicting these coupling effects using theoretical models.
- To explore potential applications arising from this observed mode coupling.
Main Methods:
- Experimental observation of transmission spectra in an as-drawn optical fiber operating far from cutoff.
- Approximation of the fiber jacket as an asymmetric slab waveguide.
- Application of coupled-mode theory to predict transmission features.
Main Results:
- Observed distinct minima in the core's transmission spectrum between 1200 and 1900 nm.
- Successfully predicted the wavelengths of these transmission features using coupled-mode theory.
- Demonstrated that jacket surface conditions influence the transmission spectrum.
Conclusions:
- Mode coupling between the optical fiber core and its plastic jacket is a verifiable phenomenon.
- Coupled-mode theory provides an effective framework for predicting these spectral features.
- The sensitivity of the transmission spectrum to jacket surface conditions opens avenues for novel environmental sensing technologies.
Related Concept Videos
01:31Energy Stored In A Coaxial Cable
A coaxial cable consists of a central copper conductor used for transmitting signals, followed by an insulator shield, a metallic braided mesh that prevents signal interference, and a plastic layer that encases the entire assembly.
In the simplest form, a coaxial cable can be represented by two long hollow concentric cylinders in which the current flows in opposite directions. The magnetic field inside and outside the coaxial cable is determined by using Ampère's law. The magnetic field inside...
In the simplest form, a coaxial cable can be represented by two long hollow concentric cylinders in which the current flows in opposite directions. The magnetic field inside and outside the coaxial cable is determined by using Ampère's law. The magnetic field inside...
01:23Transmission Line Design Considerations
Aluminum has become the material of choice for overhead transmission lines, surpassing copper due to its abundance and cost-effectiveness. The most prevalent type is the aluminum conductor, steel-reinforced (ACSR), which combines aluminum strands around a steel core. Other variants include all-aluminum conductors (AAC), all-aluminum alloy conductors (AAAC), aluminum conductor alloy-reinforced (ACAR), and aluminum-clad steel conductors. Advanced designs, such as aluminum conductors with steel...
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.
01:20Spin–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...
01:30Propagation Speed of Electromagnetic Waves
Electromagnetic waves are consistent with Ampere's law. Assuming there is no conduction current Ampere's law is given as:
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...