Chip-Scale, Sub-Hz Fundamental Sub-kHz Integral Linewidth 780 nm Laser through Self-Injection-Locking a Fabry-P\'erot laser to an Ultra-High Q Integrated Resonator

Today's state of the art precision experiments in quantum, gravimetry, navigation, time keeping, and fundamental science have strict requirements on the level and spectral distribution of laser frequency noise. For example, the laser interaction with atoms and qubits requires ultra-low frequency noise at multiple offset frequencies due to hyperfine atomic transitions, motional sidebands, and fast pulse sequencing. Chip-scale integration of lasers that meet these requirements is essential for reliability, low-cost, and weight. Here, we demonstrate a significant advancement in atomic precision light sources by realizing a chip-scale, low-cost, 780 nm laser for rubidium atom applications with record-low 640 mHz (white noise floor at 0.2 Hz$^2$/Hz) fundamental and 732 Hz integral linewidths and a frequency noise that is multiple orders of magnitude lower than previous hybrid and heterogeneous self-injection locked 780 nm lasers and lower noise than bulk microresonator implementations. The laser is a Fabry-P\'erot laser diode self-injection locked to an ultra-high Q photonic integrated silicon nitride resonator. This performance is enabled by a 145 million resonator Q with a 30 dB extinction ratio, the highest Q at 780 nm, to the best of our knowledge. We analyze the impact of our frequency noise on specific atomic applications including atomic frequency references, Rydberg quantum gates, and cold atom gravimeters. The photonic integrated resonator is fabricated using a CMOS foundry-compatible, wafer-scale process, with demonstrated integration of other components showing promise for a full system-on-a-chip. This performance is scalable to other visible atomic wavelengths, opening the door to a variety of transitions across many atomic species and enabling low-power, compact, ultra-low noise lasers impacting applications including quantum sensing, computing, clocks and more.

[1]  K. Vahala,et al.  High-coherence hybrid-integrated 780 nm source by self-injection-locked second-harmonic generation in a high-Q silicon-nitride resonator , 2023, Optica.

[2]  M. Tran,et al.  Photonic integration platform for rubidium sensors and beyond , 2023, Optica.

[3]  Zhenda Xie,et al.  A Compact Self-Injection-Locked Narrow-Linewidth Diode Laser with Narrowband Dielectric Filter , 2023, Applied Sciences.

[4]  K. Vahala,et al.  Hydroxyl ion absorption in on-chip high-Q resonators. , 2023, Optics letters.

[5]  Min Chul Shin,et al.  Widely tunable and narrow-linewidth chip-scale lasers from near-ultraviolet to near-infrared wavelengths , 2022, Nature Photonics.

[6]  D. Blumenthal,et al.  Photonic integrated beam delivery for a rubidium 3D magneto-optical trap , 2022, Nature communications.

[7]  D. Blumenthal,et al.  Sub-dB/m loss integrated 103 and 90 million Q resonators for laser stabilization at rubidium and strontium wavelengths , 2022, 2022 IEEE Photonics Conference (IPC).

[8]  D. Blumenthal,et al.  Silicon nitride stress-optic microresonator modulator for optical control applications. , 2022, Optics express.

[9]  D. Blumenthal,et al.  Photonic integrated cascade-inhibited Brillouin laser with sub-100-mHz fundamental linewidth , 2022, 2022 Conference on Lasers and Electro-Optics (CLEO).

[10]  R. Heideman,et al.  850 nm hybrid-integrated tunable laser with Si3N4 micro-ring resonator feedback circuits , 2022, 2022 Optical Fiber Communications Conference and Exhibition (OFC).

[11]  P. Rakich,et al.  Ultralow 0.034 dB/m loss wafer-scale integrated photonics realizing 720 million Q and 380 μW threshold Brillouin lasing. , 2022, Optics letters.

[12]  A. Niggebaum,et al.  Quantum sensing for gravity cartography , 2022, Nature.

[13]  D. Blumenthal,et al.  Ultra-low loss visible light waveguides for integrated atomic, molecular, and quantum photonics. , 2022, Optics express.

[14]  N. S. Blunt,et al.  Multi-qubit entanglement and algorithms on a neutral-atom quantum computer , 2021, Nature.

[15]  Grant M. Brodnik,et al.  36 Hz integral linewidth laser based on a photonic integrated 4.0-meter coil resonator , 2021, Optica.

[16]  T. Kippenberg,et al.  Near ultraviolet photonic integrated lasers based on silicon nitride , 2021, APL Photonics.

[17]  Grant M. Brodnik,et al.  Thermal and driven noise in Brillouin lasers , 2021, Physical Review A.

[18]  J. Kitching,et al.  High-performance, compact optical standard. , 2021, Optics letters.

[19]  P. Rakich,et al.  Visible light photonic integrated Brillouin laser , 2021, Nature Communications.

[20]  C. Roeloffzen,et al.  Hybrid integrated InP-Si3N4 diode laser with a 40-Hz intrinsic linewidth. , 2020, Optics express.

[21]  Danny Eliyahu,et al.  780 nm narrow-linewidth self-injection-locked WGM lasers , 2020, LASE.

[22]  T. C. Briles,et al.  Architecture for the photonic integration of an optical atomic clock , 2019, Optica.

[23]  Daniel J. Blumenthal,et al.  Silicon Nitride in Silicon Photonics , 2018, Proceedings of the IEEE.

[24]  E. Diamanti,et al.  Quantum technologies in space , 2018, Experimental Astronomy.

[25]  Sylvain Schwartz,et al.  High-Fidelity Control and Entanglement of Rydberg-Atom Qubits. , 2018, Physical review letters.

[26]  D. Barredo,et al.  Analysis of imperfections in the coherent optical excitation of single atoms to Rydberg states , 2018, 1802.10424.

[27]  Grant M. Brodnik,et al.  Sub-hertz fundamental linewidth photonic integrated Brillouin laser , 2018, Nature Photonics.

[28]  Ian Coddington,et al.  Compact Optical Atomic Clock Based on a Two-Photon Transition in Rubidium , 2018, 1903.11231.

[29]  A. Landragin,et al.  Influence of lasers propagation delay on the sensitivity of atom interferometers , 2007, physics/0701023.

[30]  John Kitching,et al.  Chip-scale atomic devices , 2006, Applied Physics Reviews.

[31]  Theodor W. Hänsch,et al.  A compact grating-stabilized diode laser system for atomic physics , 1995 .

[32]  V. Candelier,et al.  A limit to the frequency stability of passive frequency standards due to an intermodulation effect , 1990, IEEE Transactions on Instrumentation and Measurement.

[33]  R. G. Beausoleil,et al.  Semiconductor Laser Stabilization By External Optical Feedback , 1989, Photonics West - Lasers and Applications in Science and Engineering.

[34]  G. J. Dick,et al.  Local Oscillator Induced Instabilities in Trapped Ion Frequency Standards , 1987 .

[35]  D. Blumenthal,et al.  Tunable Integrated 118 Million Q Reference Cavity for 780 nm Laser Stabilization and Rubidium Spectroscopy , 2023, CLEO 2023.