Method and system for first-order RF amplitude and bias control of a modulator

A system for robustly controlling the bias point and RF amplitude level of a modulator for an optical transmitter, comprising:

• a laser for providing an input light;
• a modulator to modulate said input light and generate said digital optical output signal;
• a splitter to split said digital optical output signal into a transmitter output signal and an output dither signal component;
• a photodiode to provide a feedback signal;
• a radio frequency (RF) feedback loop to control an RF amplitude input voltage to said modulator;
• a bias feedback loop to control a bias input voltage to said modulator;
• an RF amplitude dither circuit to provide an RF input dither signal to said RF amplitude input voltage;
• a bias dither circuit to provide a bias input dither signal to said bias input voltage;
• and
• an RF input amplifier to receive and amplify an RF data input signal.

A system for robustly controlling the bias point and RF amplitude level of a modulator for an optical transmitter, comprising

• a laser for providing an input light;
• a modulator to modulate said input light and generate said digital optical output signal;
• a splitter to split said digital optical output signal into a transmitter output signal and an output dither signal component;
• a photodiode to provide a feedback signal;
• a radio frequency (RF) feedback loop to control an RF amplitude input voltage to said modulator;
• a bias feedback loop to control a bias input voltage to said modulator;
• a dither circuit to provide an input dither signal to either said RF amplitude input voltage or said bias input voltage;
• synchronized selectors to select either said RF amplitude input voltage or said bias input voltage to receive said input dither signal;
• and
• an RF input amplifier to receive and amplify an RF amplitude input signal.