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Opto-Electronic Oscillator Stabilized By A Hyperfine Atomic Transition

Dmitry Strekalov, David C. Aveline, Andrey B. Matsko, Robert J. Thompson, Nan Yu

Published Sep 1, 2004• 3 citations
OpenAlex

Abstract

Opto-electronic oscillator (OEO) is a closed-loop system with part of the loop is implemented by an optical beam, and the rest by RF circuitry. The technological advantage of this approach over traditional all-RF loops in the gigahertz range comes from the that frequency filtering can be done far more efficiently in the optical range with compact, low power, and have superior stability. In this work, we report our preliminary results on using the phenomenon of coherent population trapping in (87) Rb vapor as an optical filter. Such a filter allows us to stabilize the OEO at the hyperfine splitting frequency of rubidium, thus implementing a novel type of frequency standard.

Related papers

Frequency pulling effect of an intraloop atomic filter in an optoelectronic oscillator

Dae Han Seo, Sin Hyuk Yim

The frequency pulling effect in an optoelectronic oscillator (OEO) due to the high dispersion produced by coherent population trapping (CPT) resonance in an intraloop Rb85 cell has been experimentally measured. With the direct modulation of the injection current of an extended-cavity diode laser, we construct the OEO and a beating signal with a frequency of 3.036 GHz is filtered by CPT resonance. The effective total loop length of the OEO under the CPT resonance condition can be significantly increased. As the optical path length of the OEO is changed, the microwave-frequency shift of the OEO corresponding to the effective total loop length is measured and reported.

Applied Optics•Jan 18, 2017•2 citations

Atomic Frequency Standard based on Coherent Population Trapping in Rb-87 Atoms for Space Application

Pragya Tiwari, Manjula Ramachandra, Madan Mohan Kandpal +11 more

Space-borne atomic frequency standards demand a high level of performance and stability throughout the mission life in the harsh environment of space. Recently, atomic clocks employing Coherent Population Trapping (CPT), a quantum interference phenomenon in alkali atoms, have shown much promise for space application. This paper presents the development and realization of compact and reliable CPT atomic clock for ISRO's navigational satellites. In our approach, quantum interference in Rb-87 atoms are pursued for obtaining the clock resonance, owing to their larger ground state hyperfine transition energy (higher Q-factor). Quantum interference is realized by generating two resonant optical laser fields from a VCSEL diode by modulating its drive current at RF frequency which corresponds to the ground state hyperfine separation in Rb-87 atoms. The emission frequency of the laser diode is stabilized by locking it with respect to the D1 hyperfine transition with the help of a servo control loop, thereby the instabilities associated with laser frequency fluctuations are minimized. The resulting CPT resonance (<;kHz) as shown in Figure 1 is used as reference to stabilize the crystal oscillator frequency (10 MHz) that serves both as clock output and seed for generating the RF field.

URSI Asia-Pacific Radio Science Conference•Mar 1, 2019•0 citations

A Quantum-Enhanced Feedback Oscillator

Hudson A. Loughlin, Daniel M. DeSantis, Nergis Mavalvala +1 more

Feedback oscillators, such as lasers and masers, serve as time references in modern computing, communication, and measurement. Quantum fluctuations ultimately limit their phase stability and ability to keep time precisely; in the absence of quantum engineering, their phase stability is bounded by a standard quantum limit (SQL). Techniques to improve the frequency stability of feedback oscillators beyond the SQL have been theorized, but have not yet been demonstrated. We demonstrate an opto-electronic oscillator (OEO), a type of feedback oscillator, with phase stability approaching the SQL. We then engineer the OEO's quantum state to improve its phase stability, thereby demonstrating the essential principle quantum-enhancement of feedback oscillators. Similar techniques may be employed to evade the SQL in other feedback oscillators such as masers and lasers.

quant-pharXiv:2608.07753•Aug 11, 2026•0 citations

Optoelectronic oscillator stabilized to an intra-loop atomic filter with a coherent population trapping resonance

Sin Hyuk Yim, D. Cho

We report the construction and characterization of an optoelectronic oscillator stabilized to an intra-loop 85Rb cell with a 3.036-GHz coherent population trapping (CPT) resonance. We use an extended-cavity diode laser (ECDL) as a light source and directly modulate its injection current by using the beating signal filtered by the CPT resonance. Use of the ECDL guarantees stability of the carrier frequency and eliminates a bulky and power-consuming external modulator. We also adjust the cavity length and operate the ECDL in multimode in order to achieve a high modulation efficiency. To further improve the oscillator’s frequency stability, we incorporate a negative feedback system based on a CPT dispersion. The Allan deviation of the oscillator frequency is 3 × 10 −10 at a 100-s integration time.

Journal of the Korean Physical Society•Jul 1, 2012•3 citations

VCSEL-based Raman frequency reference on Rubidium atoms

Laurent P. Balet, Jacques Haesler, Steve Lecomte

As an alternative to coherent population trapping (CPT), stimulated Raman scattering in an atomic vapor and implemented in an optoelectronic microwave oscillator can be designed as a compact microwave frequency reference. Due to its simplified architecture and as an active atomic clock, it has the potential to be less energy demanding than CPT. In this paper, we present experimental results on the behavior and frequency stability of a tabletop Raman oscillator.

European Frequency and Time Forum•Apr 1, 2012•1 citation

An atomic clock based on the transient coherent population trapping detuning oscillation phenomenon

Zhong Wang, Tao Guo, Ke Deng +1 more

We have theoretically and experimentally proven that the transient transmitted laser power through a typical Λ system atomic cell near Coherent Population Trapping resonance presents as a damping oscillation. The oscillating frequency is identical to the frequency detuning from the atomic hyperfine splitting. Based on the transient coherent population trapping (TCPT) phenomenon, we have proposed an atomic clock in which the standard frequency is obtained by compensated the TCPT oscillating frequency to the RF modulating frequency. Therefore we do not need to lock the RF frequency. There will be advantages for atomic clock miniaturization and stabilization.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Jun 1, 2010•4 citations
Opto-electronic oscillator (OEO) is a closed-loop system with part of the loop is implemented by an optical beam, and the rest by RF circuitry. The technological advantage of this approach over traditional all-RF loops in the gigahertz range comes from the that frequency filtering can be done far more efficiently in the optical range with compact, low power, and have superior stability. In this work, we report our preliminary results on using the phenomenon of coherent population trapping in (87) Rb vapor as an optical filter. Such a filter allows us to stabilize the OEO at the hyperfine splitting frequency of rubidium, thus implementing a novel type of frequency standard.
The frequency pulling effect in an optoelectronic oscillator (OEO) due to the high dispersion produced by coherent population trapping (CPT) resonance in an intraloop Rb85 cell has been experimentally measured. With the direct modulation of the injection current of an extended-cavity diode laser, we construct the OEO and a beating signal with a frequency of 3.036 GHz is filtered by CPT resonance. The effective total loop length of the OEO under the CPT resonance condition can be significantly increased. As the optical path length of the OEO is changed, the microwave-frequency shift of the OEO corresponding to the effective total loop length is measured and reported.
Space-borne atomic frequency standards demand a high level of performance and stability throughout the mission life in the harsh environment of space. Recently, atomic clocks employing Coherent Population Trapping (CPT), a quantum interference phenomenon in alkali atoms, have shown much promise for space application. This paper presents the development and realization of compact and reliable CPT atomic clock for ISRO's navigational satellites. In our approach, quantum interference in Rb-87 atoms are pursued for obtaining the clock resonance, owing to their larger ground state hyperfine transition energy (higher Q-factor). Quantum interference is realized by generating two resonant optical laser fields from a VCSEL diode by modulating its drive current at RF frequency which corresponds to the ground state hyperfine separation in Rb-87 atoms. The emission frequency of the laser diode is stabilized by locking it with respect to the D1 hyperfine transition with the help of a servo control loop, thereby the instabilities associated with laser frequency fluctuations are minimized. The resulting CPT resonance (<;kHz) as shown in Figure 1 is used as reference to stabilize the crystal oscillator frequency (10 MHz) that serves both as clock output and seed for generating the RF field.
Feedback oscillators, such as lasers and masers, serve as time references in modern computing, communication, and measurement. Quantum fluctuations ultimately limit their phase stability and ability to keep time precisely; in the absence of quantum engineering, their phase stability is bounded by a standard quantum limit (SQL). Techniques to improve the frequency stability of feedback oscillators beyond the SQL have been theorized, but have not yet been demonstrated. We demonstrate an opto-electronic oscillator (OEO), a type of feedback oscillator, with phase stability approaching the SQL. We then engineer the OEO's quantum state to improve its phase stability, thereby demonstrating the essential principle quantum-enhancement of feedback oscillators. Similar techniques may be employed to evade the SQL in other feedback oscillators such as masers and lasers.
We report the construction and characterization of an optoelectronic oscillator stabilized to an intra-loop 85Rb cell with a 3.036-GHz coherent population trapping (CPT) resonance. We use an extended-cavity diode laser (ECDL) as a light source and directly modulate its injection current by using the beating signal filtered by the CPT resonance. Use of the ECDL guarantees stability of the carrier frequency and eliminates a bulky and power-consuming external modulator. We also adjust the cavity length and operate the ECDL in multimode in order to achieve a high modulation efficiency. To further improve the oscillator’s frequency stability, we incorporate a negative feedback system based on a CPT dispersion. The Allan deviation of the oscillator frequency is 3 × 10 −10 at a 100-s integration time.
We have theoretically and experimentally proven that the transient transmitted laser power through a typical Λ system atomic cell near Coherent Population Trapping resonance presents as a damping oscillation. The oscillating frequency is identical to the frequency detuning from the atomic hyperfine splitting. Based on the transient coherent population trapping (TCPT) phenomenon, we have proposed an atomic clock in which the standard frequency is obtained by compensated the TCPT oscillating frequency to the RF modulating frequency. Therefore we do not need to lock the RF frequency. There will be advantages for atomic clock miniaturization and stabilization.