System and method for range enhanced high-speed free-space optical communication

A method for free-space optical communication, the method comprising:

• receiving, at a first modulator, an input optical signal;
• generating, at the first modulator, a modulated optical signal, wherein the modulated signal includes a plurality of modulated pulse frames, and each modulated pulse frame comprises a first number of pulses;
• receiving, at a second modulator coupled to the first modulator, the modulated signal;
• operating the second modulator to turn-off a select number of pulses in each modulated pulse frame to generate a low-duty cycle modulated signal, wherein the low-duty cycle modulated signal comprises a plurality of low-duty cycle pulse frames with each low-duty cycle pulse frame corresponding to one of the modulated pulse frames, and each low-duty cycle pulse frame comprises a second number of pulses, wherein the second number of pulses is equal to the first number of pulses minus the select number of pulses;
• receiving, at an average-power-limited optical amplifier coupled to the second modulator, the low-duty cycle modulated signal;
• generating, using the average-power limited optical amplifier, an amplified modulated signal from the low-duty cycle signal, wherein the amplified modulated signal comprises a plurality of amplified pulse frames with each amplified pulse frame defining an amplified version of a corresponding each low-duty cycle pulse frame;
• wherein each amplified pulse frame, in the amplified signal, has an average power corresponding to the average output power (Paverage) of the optical amplifier, and
• wherein each amplified pulse, in each amplified pulse frame, has an amplified pulse power that corresponds to a ratio of the average output power, wherein the ratio corresponds to a ratio of the first number of pulses to the second number of pulses, and
• wherein the amplified pulse power of each pulse in each amplified pulse frame is adjustable by adjusting the select number of pulses turned-off by the second modulator in each modulated pulse frame.