Control of a modulation index of an optical signal

An optical transmitter, comprising:

• a transmitter device configured to modulate an optical signal with a data signal;
• and
• a controller configured to:
• output the data signal to the transmitter device,
• wherein the data signal has a modulation amplitude to control a modulation of the optical signal by the transmitter device;
• obtain a feedback signal based on outputting the data signal to the transmitter device;
• determine, based on the feedback signal, an actual modulation index of the optical signal modulated with the data signal;
• and
• adjust the modulation amplitude of the data signal based on a difference between the actual modulation index and a target modulation index.

A method, comprising:

• outputting, by a controller, a low-speed data signal to a transmitter device,
• wherein the low-speed data signal has a modulation amplitude to control a modulation of an optical signal by the transmitter device,
• wherein the optical signal is to be modulated with a high-speed data signal and the low-speed data signal, and
• wherein the low-speed data signal indicates diagnostic information, associated with a controlled network node of an optical network, and for a controlling network node of the optical network;
• obtaining, by the controller and based on outputting the low-speed data signal to the transmitter device, a feedback signal generated by a photodetector based on the optical signal modulated with at least the low-speed data signal;
• determining, by the controller and based on the feedback signal, an actual modulation index of the optical signal modulated with at least the low-speed data signal;
• and
• adjusting, by the controller, the modulation amplitude of the low-speed data signal based on a difference between the actual modulation index and a target modulation index.