Characterizing a Fiber-Based Frequency Comb With Electro-Optic Modulator

Laboratoire National de Métrologie et Essais-Systèmes de Référence Temps et Espace (LNE-SYRTE), Observatoire de Paris, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Paris, France.
IEEE transactions on ultrasonics, ferroelectrics, and frequency control (Impact Factor: 1.51). 03/2012; 59(3):432-8. DOI: 10.1109/TUFFC.2012.2212
Source: PubMed


We report on the characterization of a commercial- core fiber-based frequency comb equipped with an intracavity free-space electro-optic modulator (EOM). We investigate the relationship between the noise of the pump diode and the laser relative intensity noise (RIN) and demonstrate the use of a low-noise current supply to substantially reduce the laser RIN. By measuring several critical transfer functions, we evaluate the potential of the EOM for comb repetition rate stabilization. We also evaluate the coupling to other relevant parameters of the comb. From these measurements, we infer the capabilities of the femtosecond laser comb to generate very-low-phase-noise microwave signals when phase-locked to a high-spectral-purity ultra-stable laser.

  • [Show abstract] [Hide abstract]
    ABSTRACT: We present here a detailed investigation of a commercial-core Erbium-doped fiber-based femtosecond laser optical frequency comb equipped with an intra-cavity Electro-Optics modulator. This device allows rapid feed-back on the laser's repetition rate, enabling reaching the narrow-linewidth regime when locked to a ultra-high spectral purity optical continuous wave reference. Our study makes use of transfer functions analysis to characterize the laser dynamic response and the residual unavoidable cross talks. In a second part, we also present some results which show how to combine the signals from two photodetector to obtain a very low amplitude-phase conversion detection of the repetition rate, which is very useful in the context of low phase noise microwave generation with optical frequency combs.
    No preview · Conference Paper · Jan 2012
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present a study of the impact of the cross-coupling between the two servo loops used to stabilize the repetition rate frep and the carrier-envelope offset (CEO) frequency fCEO 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 frep and fCEO. 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.
    Full-text · Article · Oct 2012 · Journal of the Optical Society of America B
  • [Show abstract] [Hide abstract]
    ABSTRACT: We propose a novel, high-performance, and practical laser source system for optical clocks. The laser linewidth of a fiber-based frequency comb is reduced by phase locking a comb mode to an ultrastable master laser at 1064 nm with a broad servo bandwidth. A slave laser at 578 nm is successively phase locked to a comb mode at 578 nm with a broad servo bandwidth without any pre-stabilization. Laser frequency characteristics such as spectral linewidth and frequency stability are transferred to the 578-nm slave laser from the 1064-nm master laser. Using the slave laser, we have succeeded in observing the clock transition of <sup>171</sup>Yb atoms confined in an optical lattice with a 20-Hz spectral linewidth.
    No preview · Article · Apr 2013 · Optics Express
Show more