Nonlinearity compensation using pilot tones

An optical system, comprising:

• an optical transmitter configured to:
• receive a signal channel,
• add data corresponding to a pilot tone having a phase to the signal channel,
• generate a digital signal associated with the signal channel, the digital signal including the pilot tone,
• convert the digital signal to an analog signal,
• modulate an optical signal based on the analog signal to form a modulated optical signal having the pilot tone, and
• output the modulated optical signal;
• and
• an optical receiver configured to:
• receive the modulated optical signal,
• process the modulated optical signal to determine the phase associated with the pilot tone, and
• apply the phase to the modulated optical signal to recover the signal channel.

An optical transmitter comprising:

• a digital signal processor (DSP) configured to:
• receive a signal channel,
• add data corresponding to a pilot tone having a phase to the signal channel,
• form a digital signal associated with the signal channel, the digital signal including the pilot tone, and
• output the digital signal;
• a digital-to-analog converter (DAC) configured to convert the digital signal to an analog signal;
• a laser configured to provide an optical signal;
• and
• a modulator configured to:
• receive the optical signal and the analog signal, and
• modulate the optical signal based on the analog signal to form a modulated optical signal having the pilot tone, and
• output the modulated optical signal for transmission to an optical receiver, the optical receiver processing the modulated optical signal to determine the phase associated with the pilot tone and applying the phase to the modulated optical signal to recover the signal channel.