Example 87h: Photonic Switch
This example illustrates some of the waveguide capabilities in GLAD. GLAD performs detailed modeling of 2D and 3D waveguides using the beam propagation method (BPM). In this example, a higher index guide region is split into two paths and, after some distance, the two paths are rejoined to form the equivalent of a Mach-Zender interferometer. Light injected into the waveguide at the upper left follows the waveguide, splits into to parts, and then recombines when the paths rejoin. If the optical path length of the two paths is identical the interference is constructive and the switch is "on". The switch may be turned "off" by raising the index of refraction in one of the legs by using an electro-optic effect to achieve a 180 degree change in optical path length.

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The centers of the waveguides is indicated. Light will enter from the left. (expand)

[lines forming waveguide]
Optical mode as they propagate through the Mach-Zender configuration from top left to lower right. Propagation is done by the BPM method. (expand)
The photonic switch shown as a contour plot. (expand)
Index of refraction distribution for the photonic switch. (expand)
Region of waveguide given higher index to cause 180 deg. phase change in the left leg. (expand)
Optical switch in the "off" position. (expand)
Destructive interference. Switch is "off" (expand).
Destructive interference (bitmap view). Switch is "off". (expand)
Destructive interference (array visualizer view). Switch is "off" (expand).