Waveguide Dispersion | <<< | >>> | Feedback |
Definition: chromatic dispersion arising from waveguiding effects
Waveguide dispersion is chromatic dispersion which arises from waveguide effects: the dispersive phase shifts for a wave in a waveguide differ from those which the wave would experience in a homogeneous medium. The total dispersion is the combination of material dispersion and waveguide dispersion.
The origin of waveguide dispersion can be understood by considering that a guided wave has a frequency-dependent distribution of k vectors, whereas a plain wave (as the reference case) has only a single k vector, which points exactly in the propagation direction. Note that chromatic dispersion for a given propagation mode of a waveguide is calculated from the frequency dependence of the so-called propagation constant, which is the overall phase shift per unit length which the guided wave experiences.
Waveguide dispersion is important in waveguides with small effective mode areas. Examples are optical fibers, in particular certain photonic crystal fibers, but also other single-mode fibers as used in, e.g., optical fiber communications. Waveguide dispersion may be tailored via the fiber design to obtain the desired dispersion properties; see e.g. the article on dispersion-shifted fibers. For fibers with large mode areas, waveguide dispersion is normally negligible, and material dispersion is dominant.
Bibliography
| [1] | J. A. Mores Jr et al., “Efficient calculation of higher-order optical waveguide dispersion”, Opt. Express 18 (19), 19522 (2010) |
| [2] | A. W. Snyder and J. D. Love, Optical Waveguide Theory, Chapman and Hall, London (1983) |
See also: waveguides, chromatic dispersion, dispersion-shifted fibers
