an optical phased array configured to modulate a phase of light incident on the optical phased array and emit the light that is phase-modulated;

a first photodetector configured to detect, as a reference light, the light emitted from the optical phased array in a first direction toward the first photodetector, and generate a reference signal based on the reference light;

a second photodetector configured to detect, as a target light including information about an object, the light emitted from the optical phased array in a second direction toward the object, and generate a target signal based on the target light; and

a processor configured to determine a distance between the LiDAR device and the object based on a cross-correlation between the reference signal and the target signal,

wherein the optical phased array comprises an optical splitter, a phase modulation array, and an antenna array, and

wherein the first photodetector is connected to the antenna array via a waveguide that is in contact with the antenna array and the first photodetector and configured to receive the reference light used to determine the distance from the antenna array via the waveguide, and

wherein the optical splitter, the phase modulation array, the antenna array, the waveguide, and the first photodetector are provided on a same surface of a same substrate.