US 2026/0133462 A1Published application

Optical signal generation device and optical signal generation method

AssigneeNTT, Inc.

InventorsHiroto KAWAKAMI, Masanori NAKAMURA, Yutaka MIYAMOTO

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Abstract

An optical modulator is a Mach-Zehnder interferometer that branches light, inputs the light to first and second Mach-Zehnder type optical modulators, and combines the light outputted by each of the first and second Mach-Zehnder type optical modulators to generate a QAM signal. The first and second drive signal application electrodes change optical path lengths of first and second arms of the first Mach-Zehnder type optical modulator in accordance with first and second drive signals that are multi-level electric signals, respectively. The third and fourth drive signal application electrodes change the optical path lengths of the first and second arms of the second Mach-Zehnder type optical modulator in accordance with third and fourth drive signals that are multi-level electric signals, respectively. First to fourth drive signal generation units generate the first to fourth drive signals and apply them to the first to fourth drive signal application electrodes, respectively. The first to fourth drive signals are multi-level signals independent of each other.

Claims7

Dependent claims

An optical signal generation device comprising:

an optical modulator, that is a Mach-Zehnder interferometer, configured to branch light into first and second branched light, input the first branched light to a first Mach-Zehnder type optical modulator which includes a first arm and a second arm, input the second branched light to a second Mach-Zehnder type optical modulator which includes a third arm and a fourth arm, and combine first output light outputted from the first Mach-Zehnder type optical modulator and second output light outputted from the second Mach-Zehnder type optical modulator to generate a QAM signal;
a first drive signal application electrode configured to change a first optical path length of the first arm of the first Mach-Zehnder type optical modulator in accordance with a first drive signal that is a multi-level electric signal;
a second drive signal application electrode configured to change a second optical path length of the second arm of the first Mach-Zehnder type optical modulator in accordance with a second drive signal that is the multi-level electric signal;
a third drive signal application electrode configured to change a third optical path length of the third arm of the second Mach-Zehnder type optical modulator in accordance with a third drive signal that is the multi-level electric signal;
a fourth drive signal application electrode configured to change a fourth optical path length of the fourth arm of the second Mach-Zehnder type optical modulator in accordance with a fourth drive signal that is the multi-level electric signal;
a first drive signal generator configured to generate the first drive signal and apply the first drive signal to the first drive signal application electrode;
a second drive signal generator configured to generate the second drive signal and apply the second drive signal to the second drive signal application electrode;
a third drive signal generator configured to generate the third drive signal and apply the third drive signal to the third drive signal application electrode;
and
a fourth drive signal generator configured to generate the fourth drive signal and apply the fourth drive signal to the fourth drive signal application electrode, wherein
the first drive signal, the second drive signal, the third drive signal, and the fourth drive signal are multi-level signals independent of each other.

8 more elements

An optical signal generation method comprising:

branching light into first and second branched light, inputting the first branched light to a first Mach-Zehnder type optical modulator which includes a first arm and a second arm and inputting the second branched light to a second Mach-Zehnder type optical modulator which includes a third arm and a fourth arm;
generating a first drive signal that is a first multi-level electric signal;
generating a second drive signal that is a second multi-level electric signal;
generating a third drive signal that is a third multi-level electric signal;
generating a fourth drive signal that is a fourth multi-level electric signal;
changing a first optical path length of the first arm of the first Mach-Zehnder type optical modulator by a first drive signal application electrode in accordance with the first drive signal;
changing a second optical path length of the second arm of the first Mach-Zehnder type optical modulator by a second drive signal application electrode in accordance with the second drive signal;
changing a third optical path length of the third arm of the second Mach-Zehnder type optical modulator by a third drive signal application electrode in accordance with the third drive signal;
changing a fourth optical path length of the fourth arm of the second Mach-Zehnder type optical modulator by a fourth drive signal application electrode in accordance with the fourth drive signal;
and
combining first output light outputted by the first Mach-Zehnder type optical modulator and second output light outputted by the second Mach-Zehnder type optical modulator to generate a QAM signal, wherein
the first drive signal, the second drive signal, the third drive signal, and the fourth drive signal are multi-level signals independent of each other.

9 more elements

Dependencies are inferred from the claim text.