Widely tunable comb-locked frequency-swept synthesizer

You would like to combine wide tunability with the precision of frequency comb technology ? We can provide a unique technology: the optical synthesizer

Advantages Optical synthesizer

  • the scanning cw laser is permanently phase-locked to the frequency comb and inherits its low phase noise and precision
  • the comb’s intrinsic constant mode spacing allows a strictly linear scan
  • locking the comb allows absolute measurement that is traceable to the frequency standard
  • the scan can be on the fly adopted for various measurement conditions

Features Optical synthesizer

  • central wavelength ~ 1570 nm
  • frequency range ~ 10 THz : mode hop free
  • frequency resolution   < 0.1 Hz
  • scanning speed 100 kHz/s … 1 THz/s
  • scanning form : saw tooth, triangle
  • slew rate modulation for dispersion correction

Optical synthesizer : proved applications

R. Gotti, et al, “Comb-locked frequency-swept synthesizer for high precision broadband spectroscopy,” Sci. Rep. 10(1), 2523 (2020).

T. A. Puppe, Y. Mayzlin, J. Robinson-Tait and R. Wilk, "Comb-locked Frequency-domain terahertz spectrometer," 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Paris, France, 2019, pp. 1-1, doi: 10.1109/IRMMW-THz.2019.8874007.

Conclusion and outlook

  • The optical synthesizer is suitable for OFDR resolution of 10 mm at 20 km distance in fiber to our knowledge, it is 14 times better as the best reported up-to-date.
  • In current experiment only 0.1 % of available synthesizer scan range is utilized.
  • At the given oscillator noise, the large possible scan range is advantageous for shorter distances.
  • Locking the comb to a frequency standard allows for traceable absolute distance measurement.
  • Wide scan could allow for atmosphere dispersion correction as in dual band systems.
  • The main challenge for product development is to identify features for certain application.


Download the OSA Optical Sensor and Sensing 2021 presentation

Comb-locked frequency-swept synthesizer for ultra-precision long distance ranging