Optical quantizing unit and optical A/D converter

An optical quantizing unit having quantizing levels and comprising:

• an optical divider dividing first optical pulses to be quantized and sending each of the divided first optical pulses to each of a plurality of paths, the optical divider dividing the first optical pulses in accordance with the number of guantizing levels;
• a plurality of delay lines which delay the divided first optical pulses by different delay times, each of the delay lines receiving each of the divided first optical pulses through each of the paths;
• a plurality of optical filters passing with different transmittances the divided first optical pulses which have sent from the delay lines, respectively;
• an optical synthesizer synthesizing the respective first optical pulses which have passed through the respective optical filters;
• and
• an optical threshold filter sequentially receiving the synthesized first optical pulses from the optical synthesizer, and sending second optical pulses when light intensities of the first optical pulses are above a preset threshold value.