Travis Crain Briles

Optical lattice clocks generate pristine timing signals, which advance understanding of physics and open new application opportunities. However, the existing experimental apparatus for such clocks consists of numerous complicated subsystems, and are laborious to assemble. This Letter demonstrates the use of integrated photonics technologies to generate the free-space optical configuration needed to laser cool and trap atomic samples for a lattice clock and to create a frequency-comb supercontinuum to stabilize the lasers for the lattice clock. The authors assemble integrated photonics devices without active alignment, highlighting the potential for scalability in lattice-clock systems.

We demonstrate the formation of a complex, multi-wavelength, three-dimensional laser beam configuration with integrated metasurface (MS) optics. Our experiments support the development of a compact Sr optical-lattice clock, which leverages magneto-optical trapping at 461 nm and 689 nm without bulk free-space optics. We integrate six mm-scale metasurfaces on a fused silica substrate and illuminate them with light from optical fibers. The metasurfaces provide full control of beam pointing, divergence, and polarization to create the laser configuration for a magneto-optical trap. We report the efficiency and integration of the visible laser beam configuration, demonstrating the suitability of metasurface optics for atomic laser cooling.

Soliton microcombs provide a chip-based, octave-spanning source for self-referencing and optical metrology. We use a silicon nitride integrated photonics foundry to manufacture 280 single-chip solutions of octave-spanning microcombs on a wafer. By group-velocity dispersion (GVD) engineering with the waveguide cross section, we shape the soliton spectrum for dispersive-wave spectral enhancements at the frequencies for f-2f self-referencing. Moreover, we demonstrate the other considerations, including models for soliton spectrum design, ultra-broadband resonator external coupling, low-loss edge couplers, and the nonlinear self-interactions of few-cycle solitons. To cover the fabrication tolerance, we systematically scan 336 parameter sets of resonator width and radius, ensuring at least one device on each chip can yield an octave-spanning comb with an electronically detectable carrier-envelope offset frequency, which has been supported by our experiment. Our design and testing process permit highly repeatable creation of single-chip solutions of soliton microcombs optimized for pump operation ∼100 mW and high comb mode power for f-2f detection, which is the central component of a compact microsystem for optical metrology.

Microresonator frequency combs and their design versatility have revolutionized research areas from data communication to exoplanet searches. While microcombs in the 1550 nm band are well documented, there is interest in using microcombs in other bands. Here, we demonstrate the formation and spectral control of normal-dispersion dark soliton microcombs at 1064 nm. We generate 200 GHz repetition rate microcombs by inducing a photonic bandgap of the microresonator mode for the pump laser with a photonic crystal. We perform the experiments with normal-dispersion microresonators made from Ta2O5 and explore unique soliton pulse shapes and operating behaviors. By adjusting the resonator dispersion through its nanostructured geometry, we demonstrate control over the spectral bandwidth of these combs, and we employ numerical modeling to understand their existence range. Our results highlight how photonic design enables microcomb spectra tailoring across wide wavelength ranges, offering potential in bioimaging, spectroscopy, and photonic-atomic quantum technologies.

A mode-locked laser photonic integrated circuit with a repetition rate of 10 GHz is optically synchronized to a tantala-based photonic crystal resonator comb with a repetition rate of 200 GHz. The synchronization is achieved through regenerative harmonic injection locking using a coupled optoelectronic oscillator loop resulting in an optical frequency division factor of 20. The repetition rate of the photonic crystal resonator comb is stabilized and locked through electro-optic division. This stability is transferred to the mode-locked laser where we measure a fractional frequency instability of $8\times 10^{-11}$ at an averaging time of 10 s for the repetition rate signal of the mode-locked laser. Furthermore, we also measure the near carrier phase noise of the pulse repetition rate and estimate the integrated rms timing jitter of the pulses to be 6 ps.

We present an optical frequency division technique to transfer the timing stability of a stabilized Photonic Crystal Resonator Comb (~200 GHz repetition rate) to a chip-scaled mode-locked laser (~10 GHz repetition rate).

We demonstrate a 5.4 Tbps (90G-16QAMx15λ) DSP-free WDM coherent link and compare performance to single-λ 360G 72G-32QAM and 56G-64QAM coherent links over 100m using an integrated coil-resonator-stabilized Brillouin-laser-pumped integrated Kerr-comb.

Inverse design is used to spectrally shape Kerr microcombs via dispersion optimization. We experimentally demonstrate flexible ‘meta’ dispersion control using selective multimode hybridization in photonic crystal ring resonators and present initial comb results.

We demonstrate laser-wavelength access by design of optical parametric oscillation in photonic crystal resonators. Our experiments and theoretical modeling elucidate coupled bi-directional oscillation that we can jointly optimize for wavelength tuning and efficiency.

We present nanoresonators in which a shared photonic defect provides two distinct guiding mechanisms. Their drastically different dispersion profiles enable unconventional, near-arbitrary phase-matching for four-wave mixing, advantageous for wideband wavelength access.