Article

An agile laser with ultra-low frequency noise and high sweep linearity

Optics Express (Impact Factor: 3.53). 02/2010; 18:3284-3297. DOI: 10.1364/OE.18.003284
1 Bookmark
 · 
68 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present a method of noise suppression of laser diodes by an unbalanced Michelson fiber interferometer. The unstabilized laser source is represented by compact planar waveguide external cavity laser module, ORIONTM (Redfern Integrated Optics, Inc.), working at 1540.57 nm with a 1.5-kHz linewidth. We built up the unbalanced Michelson interferometer with a 2.09 km-long arm based on the standard telecommunication single-mode fiber (SMF-28) spool to suppress the frequency noise by the servo-loop control by 20 dB to 40 dB within the Fourier frequency range, remaining the tuning range of the laser frequency.
    Sensors 01/2014; 15(1):1342-53. · 2.05 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Very low frequency noise laser sources are key elements of many applications, such as: atom or ion optical clocks, ultra stable microwave (MW) frequency generation, gravitational wave detection , ultra stable optical frequency transfer, and so on.The laser frequency locking technique developed by Pound, Drever and Hall (PDH) is widespread as the commonly used method of laser frequency stabilization on optical cavities, and it has been successfully demonstrated on lasers of various wavelengths. It led to a fractional frequency instability lower than 10 -15 for 1 s averaging times and subhertz line width. This approach has intrinsically two weaknesses. First, it requires fine alignment of free space optical components, tight polarization adjustment, and spatial mode matching. In addition, the cavity has to be housed in a high vacuum enclosure with thermal radiation shielding. This makes the system relatively expensive, bulky and fragile. The second weakness is that the PDH method does not allow tuning the laser frequency. An alternative method is to use a two arm (Michelson or Mach-Zehnder) interferometer to measure the frequency fluctuations during a fixed time delay. This method requires a relatively large arm imbalance to obtain sufficient frequency discriminator sensitivity. Indeed, with a Michelson interferometer, the quality factor is proportional to the fiber delay. For example, using a 5 km fiber delay line the quality factor of the interferometer is about 30 billions for a 1.55 μm wavelength laser, which is equivalent to the quality factor of a 10 c m Fabry Perot cavity with finesse about 230 thousands. This stabilization technique allows a more robust, simpler, cheaper, transportable and frequency tunable laser with low frequency noise. In the experiment, the author use the frequency shifted heterodyne Michelson interferometer to stabilize laser frequency. Since the laser frequency can be chirped by setting a frequency offset onto the dem- dulation signal, the laser was called an “agile laser”.
    EFTF-2010 24th European Frequency and Time Forum; 06/2010
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present the experimental realization of a laser system for ground-to-satellite optical Doppler ranging at the atmospheric turbulence limit. Such a system needs to display good frequency stability (a few parts in 10<sup>-14</sup>) while allowing large and well-controlled frequency sweeps of ±12 GHz at rates exceeding 100 MHz/s. Furthermore it needs to be sufficiently compact and robust for transportation to different astronomical observation sites, where it is to be interfaced with satellite ranging telescopes. We demonstrate that our system fulfills those requirements and should therefore allow operation of ground to low Earth orbit satellite coherent optical links limited only by atmospheric turbulence.
    Applied Optics 10/2013; 52(30):7342-51. · 1.69 Impact Factor

Preview

Download
1 Download
Available from