Patent ID: 7403142

Claim:
An optical A/D converter comprising: an optical sampling unit which samples an optical analog signal and converts the optical analog signal into a string of first optical pulses; an optical quantizing unit which quantizes each of the first optical pulses so as to generate a string of guantized second optical pulses and outputs the quantized second optical pulses, a number of the guantized second optical pulses depending on light intensities of the first optical pulses; and a binary converter which performs binary conversion of the quantized second optical pulses, wherein the optical quantizing unit includes an optical divider which divides the first first optical pulses to be quantized and transmits the divided first optical pulses to a plurality of paths, respectively; a plurality of optical filters which transmit with different transmittances each of the divided first optical pulses, respectively; an optical synthesizer which synthesizes each of the divided first optical pulses passed through each of the optical filters; and an optical threshold filter which sequentially receives each of the divided first optical pulses that passed through each of the optical filters from the optical synthesizer, and outputs the quantized second optical pulses when light intensities of the divided first optical pulses passed through the optical filters are above a preset threshold value.