Demonstration of an Optical Atomic Clock with an Integrated Laser

Photonic integrated circuits are revolutionizing quantum optical systems as they can drastically reduce Size, Weight, Power, and Cost (SWaP-C) requirements by consolidating bulk optical components onto singular photonic chips. We demonstrate the use of an integrated photonic laser to excite the two-photon clock 5 S 1/2 ( F = 2) → 5 D 5/2 ( F = 4) transition in 87 Rb, thereby frequency-stabilizing the integrated laser to this transition. We achieve a measured fractional frequency instability of 3 × 10 –12 at 1 s of integration time, which integrates down for 130 s. This demonstrates the potential of integrated photonic lasers for broader use in future integrated quantum photonic systems, including optical atomic clocks.