Probably, i have already talked about modulators, as the speed and bandwidth drives the technology ever forward i will just introduce two types of modulators used in optic networks. Electro-absorption modulators exploit the properties of materials under the influence of electric field to modulate the light carrying signals by absorption.
This type of modulators have a drawback for having a limit to how fast you can modulate light due to material properties especially the incumbent InGaAsP where valence band offset limit the depletion of holes.
Mach-Zehnder modulators uses intensity modulation where by a pi phase change between the path length leads to modulation of light. We can also use the QCSE effect to improve the Mach-Zehnder by reducing Voltage needed to change phase to pi we can use Kramers-Kronig relation to calculate the effect of absorption coefficient change on refractive index.
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