Optical output device and method for controlling an optical transmitter

An optical module comprising:

• an optical input device to generate an electrical signal from a first optical signal;
• and
• an optical output device to generate a second optical signal, comprising:
• a combiner to combine a plurality of binary electrical signals and add a dither electrical signal having a frequency lower than a bit rate of the binary electrical signals to the binary electrical signals;
• an adjuster to adjust an amplitude of the binary electrical signals;
• a plurality of modulators to modulate the second optical signal based on the binary electrical signals to which the dither electrical signal have been added at different frequencies.

A device comprising:

• a combiner to combine a plurality of binary electrical signals;
• an adjuster to adjust an amplitude of the binary electrical signals;
• an adder to add a dither electrical signal having a frequency lower than a bit rate of the binary electrical signals to the binary electrical signals to generate a multilevel electrical signal,
• wherein the dither electrical signal is null at least one level of a plurality of levels of the multilevel electrical signal.

A method comprising:

• generating a multilevel electrical signal by:
• combining a plurality of electrical signals, the multilevel electrical signal to drive a modulator of an optical transmitter;
• adding a dither electrical signal having a frequency lower than a bit rate of the binary electrical signals on the binary electrical signals;
• and
• modulating an optical signal based on the binary electrical signals,
• wherein the dither electrical signal has a phase based on a value of the binary electrical signals and that is susceptible to change based on each of a plurality of bits of the binary electrical signals.