Optical frequency divider with division uncertainty at the 10−21 level

Yao, Yuan; Jiang, Yanyi; Yu, Hongfu; Bi, Zhiyi; Ma, Lei

doi:10.1093/nsr/nww063

Cited by 33 publications

(8 citation statements)

References 43 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: 80%

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

McGrew

Zhang

Leopardi

et al. 2019

Optica

110

108

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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: 80%

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

McGrew

Zhang

Leopardi

et al. 2019

Optica

110

108

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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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“…Optical frequency combs are able to work as a bidirectional bridge, with the optical frequency and the microwave frequency standing at the two sides. We can use frequency comb to coherently transfer the optical noise into the microwave regime, with an appropriate downconversion factor [29]. Consequently, the mixing of the microwave signals could become easier, which actually corresponds to the heterodyne beat of the optical signals.…”

Section: Updated Single Arm Locking With Optical Frequency Combmentioning

confidence: 99%

Arm locking using laser frequency comb

Wu,

Ke,

Wang

et al. 2021

Preprint

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The space-borne gravitational wave (GW) detectors, e.g., LISA, TianQin, TaiJi, will open the window in the low-frequency regime (0.1 mHz to 1 Hz) to study the highly energetic cosmic events, such as coalescences and mergers of binary black holes and neutron stars. For the sake of successful observatory of GWs, the required strain sensitivity of the detector is approximately 10 −21 /Hz 1/2 in the science band, 7 orders of magnitude better than the state of the art of the ultra-stable laser. Arm locking is therefore proposed to reduce the laser phase noise by a few orders of magnitude to relax the burden of time delay interferometry. During the past two decades, various schemes have been demonstrated by using single or dual arms between the spacecraft, with consideration of the gain, the nulls in the science band, and the frequency pulling characteristics, etc. In this work, we describe an updated version of single arm locking, and the noise amplification due to the nulls can be flexibly restricted with the help of optical frequency comb. We show that, the laser phase noise can be divided by a specific factor with optical frequency comb as the bridge. The analytical results indicate that, the peaks in the science band have been greatly reduced. The performance of the noise suppression shows that the total noise after arm locking can well satisfy the requirement of time delay interferometry, even with the free-running laser source. When the laser source is pre-stabilized to a Fabry-Perot cavity or a Mach-Zehnder interferometer, the noise can reach the floor determined by the clock noise, the spacecraft motion, and the shot noise. We also estimate the frequency pulling characteristics of the updated single arm locking, and the results suggest that the pulling rate can be tolerated, without the risk of mode hopping. Arm locking will be a valuable solution for the noise reduction in the space-borne GW detectors. We demonstrate that, with the precise control of the returned laser phase noise, the noise amplification in the science band can be efficiently suppressed based on the updated single arm locking. Not only our method allows the suppression of the peaks, the high gain, low pulling rate, it can also serve for full year, without the potential risk of locking failure due to the arm length mismatch. We finally discuss the unified demonstration of the updated single arm locking, where both the local and the returned laser phase noises can be tuned to generate the expected arm-locking sensor actually. Our work could provide a powerful method for the arm locking in the future space-borne GW detectors.

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Optical frequency divider with division uncertainty at the 10−21 level

Cited by 33 publications

References 43 publications

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

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

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

Arm locking using laser frequency comb

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Optical frequency divider with division uncertainty at the 10−21 level

Cited by 33 publications

References 43 publications

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

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

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

Arm locking using laser frequency comb

Contact Info

Product

Resources

About

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