Patent ID: 11868026
Assignee: FUJITSU LIMITED
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. An optical analog-to-digital (AD) converter comprising:
wherein the optical AD converter converts an analog signal of information included in inputted signal light into a digital signal, and is formed of N stages corresponding to a number N of bits of the digital signal,
a first optical waveguide of group 1 configured to branch and input the signal light, the group 1 including one or more waveguides;
a second optical waveguide of group 2 configured to guide reference light that is one of lights to which local light is branched as reference light, the group 2 including one or more waveguides;
a third optical waveguide of group 3 configured to guide base light that is another of the light to which the local light branched, as base light;
a light receiver configured to detect and compare light levels of the signal light and the reference light, and output a binary comparison result as a digital value of a stage of the N stages; and
an optical modulator configured to receive the base light guided by the third optical waveguide, and variably control a light level of the base light by phase modulation, based on a comparison result of the light receiver,
wherein the second optical waveguide multiplexes an output variably controlled of the optical modulator with the reference light, and guides the multiplexed light as the reference light of a next stage of the N stages, so that an N-bit digital signal is outputted in the N stages.