Single-branch Er:fiber frequency comb for precision optical metrology with 10^−18 fractional instability

Leopardi, Holly; Davila-Rodriguez, Josue; Quinlan, Franklyn; Olson, Judith; Sherman, Jeffrey J.; Diddams, Scott A.; Fortier, Tara M.

doi:10.1364/optica.4.000879

Cited by 83 publications

(46 citation statements)

References 56 publications

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“…Optical frequency synthesis introduces uncertainty that has been assessed to be well below 10 −19 , insignificant for the present experiment [23,24], but technical sources of error arising from the microwave setup may lead to inaccuracy. The nominal 10 MHz maser signal is multiplied by 100, to 1 GHz, by means of a frequency multiplier based on a phase-lockedloop.…”

Section: Experimental Schemementioning

confidence: 82%

Towards the optical second: verifying optical clocks at the SI limit

McGrew

Zhang

Leopardi

et al. 2019

Optica

115

110

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The pursuit of ever more precise measures of time and frequency is likely to lead to the eventual redefinition of the second in terms of an optical atomic transition. To ensure continuity with the current definition, based on a microwave transition between hyperfine levels in ground-state 133 Cs, it is necessary to measure the absolute frequency of candidate standards, which is done by comparing against a primary cesium reference. A key verification of this process can be achieved by performing a loop closure-comparing frequency ratios derived from absolute frequency measurements against ratios determined from direct optical comparisons. We measure the 1 S 0 → 3 P 0 transition of 171 Yb by comparing the clock frequency to an international frequency standard with the aid of a maser ensemble serving as a flywheel oscillator. Our measurements consist of 79 separate runs spanning eight months, and we determine the absolute frequency to be 518 295 836 590 863.71(11) Hz, the uncertainty of which is equivalent to a fractional frequency of 2.1 × 10 −16 .This absolute frequency measurement, the most accurate reported for any transition, allows us to close the Cs-Yb-Sr-Cs frequency measurement loop at an uncertainty of <3×10 −16 , limited by the current realization of the SI second. We use these measurements to tighten the constraints on variation of the electron-to-proton mass ratio, µ = m e /m p . Incorporating our measurements with the entire record of Yb and Sr absolute frequency measurements, we infer a coupling coefficient to gravitational potential of k µ = (−1.9 ± 9.4) × 10 −7 and a drift with respect to time oḟ µ µ = (5.3 ± 6.5) × 10 −17 /yr. arXiv:1811.05885v1 [physics.atom-ph]

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Section: Experimental Schemementioning

confidence: 82%

Towards the optical second: verifying optical clocks at the SI limit

McGrew

Zhang

Leopardi

et al. 2019

Optica

115

110

View full text Add to dashboard Cite

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“…This goal necessitates sensitive control over 2 degrees of freedom, namely, the pulse repetition rate of the oscillator f rep and the carrier-envelope offset (CEO) frequency f CEO . Currently, fractional uncertainties of f CEO below 10 −20 [13] as well as narrow optical comb modes with only a few millihertz bandwidth are supported by both actively controlled solid-state [14] and fiber laser systems [15]. In particular, most ultrastable and precise sources are based on mode-locked Ti:sapphire and Er:fiber oscillators with broadband gain spectra centered at 370 THz (wavelength of 810 nm) and 193 THz (1550 nm), respectively.…”

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confidence: 99%

Deterministic Nonlinear Transformations of Phase Noise in Quantum-Limited Frequency Combs

et al. 2019

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Optical phase noise of femtosecond lasers is analyzed over various steps of broadband nonlinear frequency conversion. The intrinsic phase jitter of our system originates from quantum statistics in the mode-locked oscillator. Supercontinuum generation by four-wave-mixing processes preserves a noise minimum at the optical carrier frequency. From there, a quadratic increase of the comb linewidth results with mutually anticorrelated phase fluctuations of both spectral wings. Passive phase locking by difference frequency generation strongly enhances the optical phase noise to a level equaling the carrier-envelope phase jitter of the fundamental comb. The same value results from quadratic extrapolation of the optical phase noise to radio frequencies. Our findings are consistent with a fully deterministic transformation of phase noise according to the elastic tape model.

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“…The single branch approach uses a broadband comb spanning over all required source and target wavelengths. The broadband comb either originates from a single branch of the comb generation system [22][23][24][25][26] or is generated in two distinct branches which are actively stabilized to each other [27]. However, broadband supercontinuum generation from a narrow seed comb often involves multiple nonlinear conversion mechanisms with different spatio-temporal sensitivities.…”

Section: Introductionmentioning

confidence: 99%

End-to-end topology for fiber comb based optical frequency transfer at the 10⁻²¹level

et al. 2019

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We introduce a simple and robust scheme for optical frequency transfer of an ultra-stable source light field via an optical frequency comb to a field at a target optical frequency, where highest stability is required, e.g. for the interrogation of an optical clock. The scheme relies on a topology for end-to-end suppression of the influence of optical path-length fluctuations, which is attained by actively phase-stabilized delivery, combined with common-path propagation. This approach provides a robust stability improvement without the need for additional isolation against environmental disturbances such as temperature, pressure or humidity changes. We measure residual frequency transfer instabilities by comparing the frequency transfers carried out with two independent combs simultaneously. Residual fractional frequency instabilities between two systems of 8 × 10 −18 at 1 s and 3 × 10 −21 at 10 5 s averaging time are observed. We discuss the individual noise contributions to the residual instability. The presented scheme is technically simple, robust against environmental parameter fluctuations, and enables an ultra-stable frequency transfer, e.g. to optical clock lasers or to lasers in gravitational wave detectors.

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Single-branch Er:fiber frequency comb for precision optical metrology with 10^−18 fractional instability

Cited by 83 publications

References 56 publications

Towards the optical second: verifying optical clocks at the SI limit

Towards the optical second: verifying optical clocks at the SI limit

Deterministic Nonlinear Transformations of Phase Noise in Quantum-Limited Frequency Combs

End-to-end topology for fiber comb based optical frequency transfer at the 10⁻²¹level

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Single-branch Er:fiber frequency comb for precision optical metrology with 10^−18 fractional instability

Cited by 83 publications

References 56 publications

Towards the optical second: verifying optical clocks at the SI limit

Towards the optical second: verifying optical clocks at the SI limit

Deterministic Nonlinear Transformations of Phase Noise in Quantum-Limited Frequency Combs

End-to-end topology for fiber comb based optical frequency transfer at the 10−21level

Contact Info

Product

Resources

About

End-to-end topology for fiber comb based optical frequency transfer at the 10⁻²¹level