12 research outputs found
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/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
Photonic integrated beam delivery in a rubidium 3D magneto-optical trap
Cold atoms are important for precision atomic applications including
timekeeping and sensing. The 3D magneto-optical trap (3D-MOT), used to produce
cold atoms, will benefit from photonic integration to improve reliability and
reduce size, weight, and cost. These traps require the delivery of multiple,
large area, collimated laser beams to an atomic vacuum cell. Yet, to date, beam
delivery using an integrated waveguide approach has remained elusive. We report
the demonstration of a 87Rb 3D-MOT using a fiber-coupled photonic integrated
circuit to deliver all beams to cool and trap > 1 x 10^6 atoms to near 200
{\mu}K. The silicon nitride photonic circuit transforms fiber-coupled 780 nm
cooling and repump light via waveguides to three mm-width non-diverging
free-space cooling and repump beams directly to the rubidium cell. This planar,
CMOS foundry-compatible integrated beam delivery is compatible with other
components, such as lasers and modulators, promising system-on-chip solutions
for cold atom applications
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Fully symmetric controllable integrated three-resonator photonic molecule
Photonic molecules can be used to realize complex optical energy states and
modes, analogous to those found in molecules, with properties useful for
applications like spectral engineering and quantum optics. It is desirable to
implement photonic molecules using high quality factor photonic integrated ring
resonators due to their narrow atom-like spectral resonance, tunability, and
the ability to scale the number of resonators on a photonic circuit. However,
to take full advantage of molecule spectral complexity and tuning degree of
freedom, resonator structures should have full symmetry in terms of
inter-resonator coupling and resonator-waveguide coupling as well as
independent resonance tuning, and low power dissipation operation, in a
scalable integration platform. To date, photonic molecule symmetry has been
limited to dual- and triple-cavity geometries coupled to single- or
dual-busses, and resonance tuning limited to dual resonator molecules. In this
paper, we demonstrate a three-resonator photonic molecule, consisting of
symmetrically coupled 8.11 million intrinsic Q silicon nitride rings, where
each ring is coupled to the other two rings. The resonance of each ring, and
that of the collective molecule, is controlled using low power dissipation,
monolithically integrated thin-film lead zirconate titanate (PZT) actuators
that are integrated with the ultra-low loss silicon nitride resonators. This
performance is achieved without undercut waveguides, yielding the highest Q to
date for a PZT controlled resonator. This advance leads to full control of
complex photonic molecule resonance spectra and splitting in a wafer-scale
integration platform. The resulting six tunable supermodes can be fully
controlled, including degeneracy, location and splitting as well as designed by
a model that can accurately predict the energy modes and transmission spectrum
and tunable resonance splitting
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Photonic integrated beam delivery for a rubidium 3D magneto-optical trap.
Cold atoms are important for precision atomic applications including timekeeping and sensing. The 3D magneto-optical trap (3D-MOT), used to produce cold atoms, will benefit from photonic integration to improve reliability and reduce size, weight, and cost. These traps require the delivery of multiple, large area, collimated laser beams to an atomic vacuum cell. Yet, to date, beam delivery using an integrated waveguide approach has remained elusive. Here we report the demonstration of a 87Rb 3D-MOT using a fiber-coupled photonic integrated circuit to deliver all beams to cool and trap > 1 ×106 atoms to near 200 μK. The silicon nitride photonic circuit transforms fiber-coupled 780 nm cooling and repump light via waveguides to three mm-width non-diverging free-space cooling and repump beams directly to the rubidium cell. This planar, CMOS foundry-compatible integrated beam delivery is compatible with other components, such as lasers and modulators, promising system-on-chip solutions for cold atom applications
Supplementary document for Integrated programmable fully-coupled three bus-ring resonator photonic molecule with ultra-low power piezo-electric control - 6342980.pdf
Supplemental Inf
36 Hz integral linewidth laser based on a photonic integrated 4.0-meter coil resonator
Laser stabilization sits at the heart of many precision scientific
experiments and applications, including quantum information science, metrology
and atomic timekeeping. These systems narrow the laser linewidth and stabilize
the carrier by use of Pound-Drever-Hall (PDH) locking to a table-scale,
ultra-high quality factor (Q), vacuum spaced Fabry-Perot reference cavity.
Integrating these cavities, to bring characteristics of PDH stabilization to
the chip-scale, is critical to reduce their size, cost, and weight, and enable
a wide range of portable and system-on-chip applications. We report a
significant advance in integrated laser linewidth narrowing, stabilization and
noise reduction, by use of a photonic integrated 4.0-meter-long coil resonator
to stabilize a semiconductor laser. We achieve a 36 Hz 1/{\pi}-integral
linewidth, an Allan deviation (ADEV) of 1.8x10^{-13} at 10 ms measurement time,
and a 2.3 kHz/sec drift, to the best of our knowledge the lowest integral
linewidth and highest stability demonstrated for an integrated reference
cavity. Two coil designs, stabilizing lasers operating at 1550 nm and 1319 nm
are demonstrated. The resonator is bus coupled to a 4.0-meter-long coil, with a
49 MHz free spectral range (FSR), a mode volume of 1.0x10^{10} {\mu}m^3 and a
142 million intrinsic Q, fabricated in a CMOS compatible, ultra-low loss
silicon nitride waveguide platform. Our measurements and simulations show that
the thermorefractive noise floor for this particular cavity is reached for
frequencies down to 20 Hz in an ambient environment with simple passive
vibration isolation and without vacuum or thermal isolation. The TRN limited
performance is estimated to be an 8 Hz 1/{\pi} integral linewidth and ADEV of
5x10^{-14} at 10 ms, opening a stability regime that heretofore has only been
available in fundamentally un-integrated systems.Comment: arXiv admin note: text overlap with arXiv:2107.0359
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Low-loss low thermo-optic coefficient Ta 2 O 5 on crystal quartz planar optical waveguides
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Integrated Reference Cavity for Dual-mode Optical Thermometry and Frequency Stabilization
Optical frequency stabilization is a critical component for precision
scientific systems including quantum sensing, precision metrology, and atomic
timekeeping. Ultra-high quality factor photonic integrated optical resonators
are a prime candidate for reducing their size, weight and cost as well as
moving these systems on chip. However, integrated resonators suffer from
temperature-dependent resonance drift due to the large thermal response as well
as sensitivity to external environmental perturbations. Suppression of the
cavity resonance drift can be achieved using precision interrogation of the
cavity temperature through the dual-mode optical thermometry. This approach
enables measurement of the cavity temperature change by detecting the resonance
difference shift between two polarization or optical frequency modes. Yet this
approach has to date only been demonstrated in bulk-optic whispering gallery
mode and fiber resonators. In this paper, we implement dual-mode optical
thermometry using dual polarization modes in a silicon nitride waveguide
resonator for the first time, to the best of our knowledge. The temperature
responsivity and sensitivity of the dual-mode TE/TM resonance difference is
180.72.5 MHz/K and 82.56 K, respectively, in a silicon nitride
resonator with a 179.9E6 intrinsic TM mode Q factor and a 26.6E6 intrinsic TE
mode Q factor. Frequency stabilization is demonstrated by locking a laser to
the TM mode cavity resonance and applying the dual-mode resonance difference to
a feedforward laser frequency drift correction circuit with a drift rate
improvement to 0.31 kHz/s over the uncompensated 10.03 kHz/s drift rate. Allan
deviation measurements with dual-mode feedforward-correction engaged shows that
a fractional frequency instability of 9.6E-11 over 77 s can be achieved