Abstract: A device may include a first waveguide with an optical input at a first port. A device may include a second waveguide. A device may include a first coupler that optically couples the first waveguide to the second waveguide at a first position. A device may include a waveguide delay arm. A device may include a second coupler that optically couples the first waveguide to the second waveguide at a second position, the second position different from the first position.

Abstract: A device may at least one laser with a first optical frequency the at least one laser stabilized to a at least one frequency reference, wherein the at least one laser is locked to the at least one frequency reference. A device may at least one photodiode and at least one laser current servo for locking the at least one laser to the at least one frequency reference. A device may at least one modulator configured to modulate a resonator, wherein the at least one frequency reference is a resonator, the resonator comprising a waveguide core and a tuner, wherein the tuner is laterally offset from the waveguide core.

Abstract: A device may include an atomic cell with a first wall. A device may include a photonic integrated circuit positioned parallel to the atomic cell first wall, the photonic integrated circuit comprising: a set of three grating emitters mounted on the photonic integrated circuit around a circumference with a spacing of around 120 degrees, wherein each grating emitter is etched to emit free-space beams on to the first wall of the atomic cell at a selected angle, wherein the selected angle in combination with the circumference results in the set of free-space beams intersecting at a location inside the atomic cell.