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Mach-Zehnder modulator (MZM)
A Mach-Zehnder modulator is a photonic component that modulates the amplitude or phase of an optical signal through interference between two waveguide arms with an electrically controlled phase difference.
How does a Mach-Zehnder modulator work?
The input signal is split into two waveguide arms. In one or both arms, a driving voltage changes the refractive index of the material (the electro-optic effect), introducing a controlled phase shift. When the arms recombine, wave interference — constructive or destructive — translates into amplitude modulation of the output optical signal.
Applications
The MZM is a key element in transmitters for high-bandwidth telecommunications systems, enabling advanced modulation formats such as PAM4 or DP-QPSK, used in 400G and faster transceivers.
Related terms
PIC (Photonic Integrated Circuit)
Coherent detection
BER
Simulating circuits with modulators
OptiSPICE lets you simulate the behavior of Mach-Zehnder modulators in the context of the whole photonic-electronic circuit.
See OptiSPICE