A multi-aperture optical system suitable for free space optical communications, FSOC, and remote sensing coherent LIDAR, comprising: a photonic integrated circuit; a spacer substrate coupled to the photonic integrated circuit; a folding element integrated into the photonic integrated circuit; a plurality of optical cells, each optical cell including: a phase shifter; a waveguide; a focusing optical element formed on the spacer substrate and configured to receive the light incident on the optical cell, and focus the light through the photonic integrated circuit and onto the folding element to couple light incident on the optical cell into the waveguide, wherein: the waveguide is integrated into the photonic integrated circuit, coupled to the phase shifter, and configured to transport the light reflected by the folding element through the phase shifter; and the phase shifter is coupled to the focusing optical element, and configured to shift a phase of an optical signal received by the focusing optical element, suitable for removing adverse effects of atmospheric turbulence on the optical signal; a beam combiner coupled to the phase shifter, and configured to combine light output from the phase shifter; and a photodetector coupled to the beam combiner to receive the combined light output from the beam combiner and output a corresponding signal, wherein the photonic integrated circuit, the spacer substrate, the plurality of optical cells, the beam combiner, and the photodetector are integrated as a single monolithically formed optical head. a photonic integrated circuit; a spacer substrate coupled to the photonic integrated circuit; a folding element integrated into the photonic integrated circuit; a plurality of optical cells, each optical cell including: a phase shifter; a waveguide; a focusing optical element formed on the spacer substrate and configured to receive the light incident on the optical cell, and focus the light through the photonic integrated circuit and onto the folding element to couple light incident on the optical cell into the waveguide, wherein: the waveguide is integrated into the photonic integrated circuit, coupled to the phase shifter, and configured to transport the light reflected by the folding element through the phase shifter; and the phase shifter is coupled to the focusing optical element, and configured to shift a phase of an optical signal received by the focusing optical element, suitable for removing adverse effects of atmospheric turbulence on the optical signal; a phase shifter; a waveguide; a focusing optical element formed on the spacer substrate and configured to receive the light incident on the optical cell, and focus the light through the photonic integrated circuit and onto the folding element to couple light incident on the optical cell into the waveguide, wherein: the waveguide is integrated into the photonic integrated circuit, coupled to the phase shifter, and configured to transport the light reflected by the folding element through the phase shifter; and the phase shifter is coupled to the focusing optical element, and configured to shift a phase of an optical signal received by the focusing optical element, suitable for removing adverse effects of atmospheric turbulence on the optical signal; the waveguide is integrated into the photonic integrated circuit, coupled to the phase shifter, and configured to transport the light reflected by the folding element through the phase shifter; and the phase shifter is coupled to the focusing optical element, and configured to shift a phase of an optical signal received by the focusing optical element, suitable for removing adverse effects of atmospheric turbulence on the optical signal; a beam combiner coupled to the phase shifter, and configured to combine light output from the phase shifter; and a photodetector coupled to the beam combiner to receive the combined light output from the beam combiner and output a corresponding signal, wherein the photonic integrated circuit, the spacer substrate, the plurality of optical cells, the beam combiner, and the photodetector are integrated as a single monolithically formed optical head.