Photonic integrated circuit temporal and frequency dispersion squint correction for optical phased array

A method comprising:

• transmitting optical signals through free space or receiving optical signals through free space using a photonic integrated circuit comprising a digital read in integrated circuit (DRIIC) layer and an optical phased array, the optical phased array comprising multiple unit cells, each unit cell comprising:
• an antenna element that transmits or receives optical signals;
• and
• a cascaded arrangement of modulators, the cascaded arrangement of modulators including multiple modulators having different response characteristics, the cascaded arrangement of modulators configured to be controlled by a DRIIC cell of the DRIIC layer to provide controllable phase and dispersion control to the optical signals
• wherein the DRIIC cell comprises:
• a demultiplexer that selects a value associated with a stream of array phase shifts received by the demultiplexer;
• a register that receives an indication of the value selected by the demultiplexer and outputs the value;
• and
• a first amplifier and a second amplifier that receive the value from the register and, based on the value, control at least one modulator of the cascaded arrangement of modulators of the unit cell;
• controlling multiple arms of the photonic integrated circuit to modify the optical signals transmitted or received by the optical phased array, wherein each arm is controllable to provide step-wise compensation of temporal squint and step-wise compensation of frequency dispersion squint;
• and
• phase-locking the arms with respect to each other using samples of the optical signals provided by photodetectors in the arms.

An apparatus comprising:

• a photonic integrated circuit comprising:
• a digital read in integrated circuit (DRIIC) layer;
• and
• an optical phased array comprising multiple unit cells, each unit cell comprising:
• means for transmitting optical signals through free space or receiving optical signals through free space;
• and
• means for providing controllable phase and dispersion control to the optical signals, the means controlled by a respective DRIIC cell of the DRIIC layer;
• means for modifying the optical signals transmitted or received by the optical phased array to provide step-wise compensation of temporal squint and step-wise compensation of frequency dispersion squint;
• and
• means for outputting samples of the optical signals, the samples used to phase-lock the optical signals with respect to one another,
• wherein each of the DRIIC cells comprises:
• a demultiplexer configured to select a value associated with a stream of array phase shifts received by the demultiplexer;
• a register configured to receive an indication of the value selected by the demultiplexer and output the value;
• and
• a first amplifier and a second amplifier configured to receive the value from the register and, based on the value, control the means for providing controllable phase and dispersion control to the optical signals.