Patent ID: 11899333
Assignee: NOKIA SOLUTIONS AND NETWORKS OY
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 23:
24. An apparatus, comprising:
an optical modulator including a parallel-nested pair of Mach-Zehnder Interferometers, each arm of the Mach-Zehnder Interferometers including one or more Electro-Absorption Modulators therein;
an electronic controller electrically connected to drive the Mach-Zehnder Interferometers such that the optical modulator outputs an optical carrier modulated according to a quadrature amplitude modulation constellation with at least five different symbols; and
wherein the electronic controller is electrically connected to:
deliver a modulating drive voltage to a first of the Electro-Absorption Modulators in a first arm of a first Mach-Zehnder Interferometer of the parallel-nested pair such that an optical carrier passing through the first Electro-Absorption Modulator of the first Mach-Zehnder Interferometer has one of two or more different non-null levels of optical phase and optical amplitude modulation, and
deliver a paired drive voltage to a second of the Electro-Absorption Modulators in a second arm of the first Mach-Zehnder Interferometer of the parallel-nested pair such that the optical carrier passing through the second Electro-Absorption Modulator of the first Mach-Zehnder Interferometer is reduced to a substantially null amplitude.