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Optical Waveguide is the layer structure
to guide the optical signals. Typical optical waveguide structures
maybe planar waveguides, channel waveguide or optical fibers. The
optical waveguide can be used as an component in integrated optical
circuit or as a transmission medium in local or long haul communication
systems. The materials for optical waveguides includes glass, polymer
or semiconductors.
Fig 1 shows the planar waveguide structure. To enable
guiding of optical energy, the refractive index of middle layer
n2 needs to meet following conditions (n2 >n1 and n2> n3).
An optical waveguide will allow one or more than one bound mode
to propagate. If only one mode is allowed to be propagated in the
optical waveguide, such waveguide is called single mode waveguide.
If more than one mode is allowed to be propagated in the optical
waveguide, such waveguide is called multimode waveguide.
(a)
(b)
(c)
Fig 1. Optical waveguide structure of (a) Planar waveguide (b)
Channel waveguide (c) Optical fiber
Additional Reference:
Polymer offers fabrication and economic
advantages for photonic integrated circuits
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