6.7 Integrated Optical Modulators
32/40
b. Mach-Zehnder modulator
Intensity modulation
Intensity divides
into two E / (2-1/2).
Intensity depends
on inteferometry.
E on two waveguides is back-to-back.
Phase change is doubled.
Destructive interferometry: /2 and - /2.
Constructive: 0 or .
Not or /2: partially interfered intensity.

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