Optical beamforming device using phased array antenna and operating method thereof

An optical beamforming device comprising:

• an RF front-end configured to transmit a plurality of RF antenna output signals, by using a phased array antenna (PAA) having a plurality of channels;
• and
• an optical beamformer configured to form a time delay for each of the plurality of channels based on an RF input signal from an RF back-end,
• wherein the optical beamformer includes:
• a linear modulator configured to generate an optical modulation signal based on the RF input signal from the RF back-end;
• a true time delay (TTD) array configured to output a plurality of output optical signals, in each of which a time delay is formed for each channel, by distributing the optical modulation signal;
• an electrical controller configured to generate an electrical control signal for controlling a degree of the time delay;
• and
• a plurality of O/E converters configured to convert the plurality of output optical signals into the plurality of RF antenna output signals, respectively;
• wherein the TTD array discretely determines the degree of the time delay according to Equation 1 below for the plurality of channels,
• tn=k(n−1)Δτ(Equation 1) where ‘n’ is a continuous order of an individual channel;
• tn is a delay time of channel n;
• ‘k’ is an integer greater than or equal to 0 as a state value according to a phase front rotation angle of the plurality of RF antenna output signals;
• and Δτ is a unit delay time,
• wherein the TTD array includes:
• a plurality of TTD circuits configured to generate the plurality of output optical signals obtained by forming time delays for the plurality of channels based on a plurality of optical distribution signals, respectively;
• and
• a power splitter configured to generate the plurality of optical distribution signals for the plurality of channels when the optical modulation signal is input,
• wherein each of the plurality of TTD circuits includes a plurality of unit cells, and
• wherein each of the unit cells includes:
• an optical switch configured to switch to a first node connected to a first path when the electrical control signal does not indicate a time delay and to switch to a second node connected to a second path longer than the first path when the electrical control signal indicates the time delay;
• and
• an optical combiner configured to connect the first path and the second path.