Optical quantization of microwave signals via distributed phase Modulation

Optical phase modulators and a continuous-wave laser diode were used to quantize microwave signals with frequencies up to 25 GHz. A 2- and 3-b optical quantizer and photonic analog-to-digital converter are demonstrated. The quantizer system is primarily limited in the optical domain by the speed of the phase modulators. Converting the optical binary data into the electrical domain limits the data acquisition to the electronic readout circuitry.