Figure 9. Dual-Nested IQ (In-Phase, Quadrature) Mach-Zehnder Modulator (with each MZM biased at minimum transmission point)

From

Principle of Coherence Optical Systems-Current Applications and Future Challenges

Arun Agarwal, Kabita Agarwal, Gourav Misra, Subrat Kumar Panda

American Journal of Electrical and Electronic Engineering. 2019, 7(4), 94-98 doi:10.12691/ajeee-7-4-2