There has been increased interest in the use and manipulation of optical fields to address the challenging problems that have traditionally been approached with microwave electronics. Some examples that benefit from the low transmission loss, agile modulation and large bandwidths accessible with coherent optical systems include signal distribution, arbitrary waveform generation and novel imaging1. We extend these advantages to demonstrate a microwave generator based on a high-quality-factor (Q) optical resonator and a frequency comb functioning as an optical-to-microwave divider. This provides a 10 GHz electrical signal with fractional frequency instability of ≤8 × 10−16 at 1 s, a value comparable to that produced by the best microwave oscillators, but without the need for cryogenic temperatures. Such a low-noise source can benefit radar systems2 and improve the bandwidth and resolution of communications and digital sampling systems3, and can also be valuable for large baseline interferometry4, precision spectroscopy and the realization of atomic time5,6,7.
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Capmany, J. & Novak, D. Microwave photonics combines two worlds. Nature Photon. 1, 319–330 (2007).
Scheer, J. A. & Kurtz, J. Coherent Radar Performance Estimation (Artech House, 1993).
Valley, G. C. Photonic analog-to-digital converters. Opt. Express 15, 1955–1982 (2007).
Doeleman, S. in Frequency standards and metrology: Proceedings of the 7th symposium (ed Maleki, L.) 175–183 (World Scientific, 2009).
Santarelli, G. et al. Quantum projection noise in an atomic fountain: a high stability cesium frequency standard. Phys. Rev. Lett. 82, 4619–4622 (1999).
Weyers, S., Lipphardt, B. & Schnatz, H. Reaching the quantum limit in a fountain clock using a microwave oscillator phase locked to an ultrastable laser. Phys. Rev. A 79, 031803 (2009).
Millo, J. et al. Ultralow noise microwave generation with fiber-based optical frequency comb and application to atomic fountain clock. Appl. Phys. Lett. 94, 141105 (2009).
Eliyahu, D., Seidel, D. & Maleki, L. in Proceedings of the IEEE International Frequency Control Symposium, 811–814 (2008).
Savchenkov, A. A., Rubiola, E., Matsko, A. B., Ilchenko, V. S. & Maleki, L. Phase noise of whispering gallery photonic hyper-parametric microwave oscillators. Opt. Express 16, 4130–4144 (2008).
Callahan, P. T., Gross, M. C. & Dennis, M. L. in 2010 IEEE Topical Meeting on Microwave Photonics (MWP), 155–158 (2010).
Bartels, A. et al. Femtosecond laser based synthesis of ultrastable microwave signals from optical frequency references. Opt. Lett. 30, 667–669 (2005).
McFerran, J. J. et al. Low noise synthesis of microwave signals from an optical source. Electron. Lett. 41, 36–37 (2005).
Zhang, W. et al. Sub-100 attoseconds stability optics-to-microwave synchronization. Appl. Phys. Lett. 96, 211105 (2010).
Young, B. C., Cruz, F. C., Itano, W. M. & Bergquist, J. C. Visible lasers with subhertz linewidths. Phys. Rev. Lett. 82, 3799–3802 (1999).
Webster, S. A., Oxborrow, M. & Gill, P. Subhertz-linewidth Nd:YAG laser. Opt. Lett. 29, 1497–1499 (2004).
Millo, J. et al. Ultrastable lasers based on vibration insensitive cavities. Phys. Rev. A 79, 053829 (2009).
Ludlow, A. D. et al. Compact, thermal-noise-limited optical cavity for diode laser stabilization at 1×10−15. Opt. Lett. 32, 641–643 (2007).
Jiang, Y. Y. et al. Making optical atomic clocks more stable with 10−16 level laser stabilization. Nature Photon. 5, 158–161 (2011).
Thorpe, M. J., Fortier, T. M., Kirchner, M. S., Rosenband, T. & Rippe, L. Frequency-stabilization to 6×10−16 via spectral hole burning. (submitted to Nature Photonics).
Mann, A. G., Sheng, C. & Luiten, A. N. Cryogenic sapphire oscillator with exceptionally high frequency stability. IEEE Trans. Instrum. Meas. 50, 519–521 (2001).
Locke, C. R., Ivanov, E. N., Hartnett, J. G., Stanwix, P. L. & Tobar, M. E. Invited article: Design techniques and noise properties of ultrastable cryogenically cooled sapphire-dielectric resonator oscillators. Rev. Sci. Instrum. 79, 051301 (2008).
Grop, S. et al. ELISA: a cryocooled 10 GHz oscillator with 10−15 frequency stability. Rev. Sci. Instrum. 81, 025102 (2010).
Grop, S. et al. 10 GHz cryocooled sapphire oscillator with extremely low phase noise. Electron. Lett. 46, 420–422 (2010).
Diddams, S. A. et al. Improved signal-to-noise ratio of 10 GHz microwave signals generated with a mode-filtered femtosecond laser frequency comb. Opt. Express 17, 3331–3340 (2009).
Ivanov, E. N. & Tobar, M. E. Low phase-noise sapphire crystal microwave oscillators: current status. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 56, 263–269 (2009).
Ma, L-S., Jungner, P., Ye, J. & Hall, J. L. Delivering the same optical frequency at two places: accurate cancellation of phase noise introduced by an optical fiber or other time-varying path. Opt. Lett. 19, 1777–1779 (1994).
Fortier, T. M., Bartels, A. & Diddams, S. A. Octave-spanning Ti:sapphire laser with a repetition rate of 1 GHz for optical frequency measurements and comparisons. Opt. Lett. 31, 1011–1013 (2006).
Taylor, J. et al. Characterization of power-to-phase conversion in high-speed P-I-N photodiodes. IEEE Photon. J. 3, 140–151 (2010).
Dawkins, S. T., McFerran, J. J. & Luiten, A. N. Considerations on the measurement of the stability of oscillators with frequency counters. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 54, 918–925 (2007).
The authors thank A. Hati, L. Hollberg, D. Howe, C. Nelson, N. Newbury and S. Papp for their contributions and comments on this manuscript, and A. Joshi and S. Datta of Discovery Semiconductor for providing the 10 GHz InGaAs photodiodes. This work was supported by NIST. It is a contribution of an agency of the US Government and is not subject to copyright in the USA. Mention of specific products or trade names does not constitute an endorsement by NIST.
The authors declare no competing financial interests.
About this article
Cite this article
Fortier, T., Kirchner, M., Quinlan, F. et al. Generation of ultrastable microwaves via optical frequency division. Nature Photon 5, 425–429 (2011). https://doi.org/10.1038/nphoton.2011.121
Towards integrated photonic interposers for processing octave-spanning microresonator frequency combs
Light: Science & Applications (2021)
Scientific Reports (2021)
Nature Photonics (2021)
Communications Physics (2021)
Ultralow-noise microwave extraction from optical frequency combs using photocurrent pulse shaping with balanced photodetection
Scientific Reports (2021)