High-speed optical analog-to-digital converter based on compressive sensing

An optical communication system, comprising:

• an optical transmitter that transmits an optical signal;
• and
• an optical receiver that receives the optical signal, wherein the optical receiver includes an optical analog-to-digital converter (ADC);
• wherein the optical ADC comprises:
• a signal input that receives an optical input signal;
• a reference input that receives a reference optical frequency comb (OFC) signal;
• a gapless spectral demultiplexer, which spectrally slices the optical input signal to produce a set of spectral slices;
• a high-contrast demultiplexer, which strongly isolates each combline of the reference OFC signal to produce a set of reference comblines;
• a demodulator, which in a parallel manner demodulates each spectral slice in the set of spectral slices centered on a single reference combline in the set of reference comblines to produce a set of baseband I/Q signals, wherein:
• the set of reference comblines pass through a set of optical modulators prior to passing into the demodulator,
• the set of optical modulators perform modulation operations on the set of reference comblines based on first known code sequences to facilitate compressive sensing, and
• each spectral slice is demodulated based on a second known code sequence;
• a set of electronic ADCs, which digitize the set of baseband I/Q signals to produce a set of digitized signals;
• and
• a digital signal processor (DSP), which processes the set of digitized signals to directly reconstruct a waveform for the optical input signal.

A method for performing an optical analog-to-digital conversion operation, comprising:

• receiving an optical input signal;
• receiving a reference optical frequency comb (OFC) signal;
• using a gapless spectral demultiplexer to spectrally slice the optical input signal to produce a set of spectral slices;
• using a high-contrast demultiplexer to strongly isolate each combline of the reference OFC signal to produce a set of reference comblines;
• performing modulation operations on the set of reference comblines based on first known code sequences to facilitate compressive sensing;
• after performing said modulation operations, and in a parallel manner, demodulating each spectral slice in the set of spectral slices centered on a single reference combline in the set of reference comblines to produce a set of baseband I/Q signals, wherein each spectral slice is demodulated based on a second known code sequence;
• digitizing the set of baseband I/Q signals to produce a set of digitized signals;
• and
• processing the set of digitized signals to directly reconstruct a waveform for the optical input signal.