The measurement of optical frequencies

Hollberg, L.; Diddams, Scott A.; Bartels, A.; Fortier, Tara M.; Kim, Kyoungsik

doi:10.1088/0026-1394/42/3/s12

Cited by 42 publications

(20 citation statements)

References 181 publications

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“…Full stabilization of a frequency comb is generally achieved using two phase-lock loops to coherently stabilize f rep and f CEO to a radio frequency (RF) reference [ 11]. Control of the laser cavity length using a piezoelectric transducer (PZT) is the traditional method of stabilizing the repetition rate, whereas the pump power is generally used to stabilize f CEO [12,13].…”

Section: Introductionmentioning

confidence: 99%

Cross-influence between the two servo loops of a fully stabilized Er:fiber optical frequency comb

et al. 2012

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We present a study of the impact of the cross-coupling between the two servo loops used to stabilize the repetition rate f rep and the carrier-envelope offset (CEO) frequency f CEO in a commercial Er:fiber frequency comb, based on the combination of experimental measurements and a model of the coupled loops. The developed theoretical model enables us to quantify the influence of the servo-loop coupling on an optical comb line, by simulating the hypothetic case where no coupling would be present. Numerical values for the model were obtained from an extensive characterization of the comb, in terms of frequency noise and dynamic response to a modulation applied to each actuator, for both f rep and f CEO . To validate the model, the frequency noise of an optical comb line at 1.56 μm was experimentally measured from the heterodyne beat between the comb and a cavity-stabilized ultranarrow-linewidth laser and showed good agreement with the calculated noise spectrum. The coupling between the two stabilization loops results in a more than 10-fold reduction of the comb mode frequency noise power spectral density in a wide Fourier frequency range.

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Section: Introductionmentioning

confidence: 99%

Cross-influence between the two servo loops of a fully stabilized Er:fiber optical frequency comb

et al. 2012

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“…Such a scheme could serve to lock several lasers on a master laser (itself locked to a strong absorption line), for instance off-line, weak line or even medium line lasers. Employing a stabilised (selfreferenced) mode-locked femtosecond laser and a suitable accurate local oscillator would even avoid the necessity of any water vapour reference [11]. However, complexity of the system might increase.…”

Section: Discussionmentioning

confidence: 99%

Frequency-stabilised laser reference system for trace-gas sensing applications from space

Matthey

Affolderbach

Mileti

et al. 2017

International Conference on Space Optics — ICSO 2006

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A four-wavelength low-power continuous-wave frequency laser reference system has been realised in the 935.4-nm range for water vapour differential absorption lidar (DIAL) applications. The system is built around laboratory extended-cavity and DFB diode lasers. Three lasers are directly locked to three water vapour absorption lines of different strength, whereas the wavelength of the fourth laser lies out of any absorption line (offline). On-line stabilisation is performed by wavelength modulation spectroscopy technique, while precise offline stabilisation is realised by an offset locking at 18.8 GHz. Offset frequency larger than 320 GHz has also been demonstrated at 1.55 μm, based on an all-fibre optical frequency comb. First steps towards the use of a photonic crystal fibre as ultra compact reference cell with long optical pathlength were realised. The developed techniques for direct and offset-lock laser stabilisation can also be applied to other gases and wavelengths, provided the required optical components are available for the laser wavelength considered.

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“…A single comb could even be used to lock several lasers on a master laser, for instance the off-line, weak-line or even medium-line lasers. Employing a stabilised (self-referenced) mode-locked femtosecond laser and a suitable accurate local oscillator would even avoid the necessity of any water-vapour reference [38].…”

Section: Discussionmentioning

confidence: 99%

Diode laser frequency stabilisation for water-vapour differential absorption sensing

et al. 2006

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We describe a low-power continuous-wave laser system for water-vapour sensing applications in the 935-nm region. The system is based on extended-cavity diode lasers and distributed-feedback lasers and delivers four single-mode frequency-stabilised optical signals. Three lasers are locked to three water-vapour absorption lines of different strengths, whereas the fourth lies outside any absorption line. On-line stabilisation is performed by wavelength-modulation spectroscopy using compact water-vapour reference cells. An offset-locking technique implemented around an electrical filter is applied for the stabilisation of the off-line slave laser to an on-line master laser at a frequency detuning of 18.8 GHz. Stabilities in the order of 15 MHz over one day were observed for the strongest lines, at the detection limit of the measurement instrumentation. The developed techniques and schemes can be applied to other wavelength ranges and molecular species. Differential absorption lidar instrumentation can in particular benefit from such a system when the stabilised lasers serve as injection seeders to pulsed power oscillators.PACS 42.62.Fi; 42.68.Wt IntroductionWater vapour is a key component in the atmosphere. As part of the global water cycle it strongly influences the surface/atmosphere interaction processes. Its phase transitions determine the transport and redistribution of energy around the globe, affecting the weather. It plays a part in many atmospheric chemistry processes and, as a major greenhouse gas, plays a central role in the climate. Improved water-vapour measurements are needed in numerous disciplines and scientific issues [1]. For meteorology, weather forecasting, climatology as well as atmospheric process studies, it is important to accurately monitor both the temporally and spatially variable water-vapour concentration, not only through point or integrated column measurements, but also with a high spatial and temporal resolution.The water-vapour differential absorption lidar (DIAL) technique provides an independent and direct manner to retrieve the atmospheric humidity profile in a continuous way, u Fax: +41-32-722-04-20, E-mail: renaud.matthey@ne.ch with a high temporal and spatial resolution [2][3][4]. It is based on the comparison of the lidar signals at two wavelengths, one coinciding with a water-vapour absorption line of adequate strength and the second sufficiently far away from any line not to undergo substantial absorption. The quality of the data obtained from ground-based [5,6] and airborne [7][8][9][10] instruments in terms of vertical resolution, precision and accuracy indicates the feasibility of a space-borne instrument [11], from which major advances in humidity profiling with global coverage are expected [12]. While ground-based water-vapour DIALs operate at two wavelengths only (one on-line and the other off-line), space-borne instruments may operate at a set of different on-line wavelengths corresponding to absorption lines of different strengths, thus providing different p...

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The measurement of optical frequencies

Cited by 42 publications

References 181 publications

Cross-influence between the two servo loops of a fully stabilized Er:fiber optical frequency comb

Cross-influence between the two servo loops of a fully stabilized Er:fiber optical frequency comb

Frequency-stabilised laser reference system for trace-gas sensing applications from space

Diode laser frequency stabilisation for water-vapour differential absorption sensing

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