TIMING DISTRIBUTION

 


TIMING DISTRIBUTION


Timing distribution for Free-Electron Lasers and particles accelerators

Ultra-stable distribution of timing signals is of high importance in academic research infrastructures such as particle accelerators. The requirements of future accelerators for stable timing are expected to increase substantially. Newest generation high brightness ultrafast x-ray sources driven by free electron lasers have typically sub-10 fs requirements on the distribution of RF signals to accelerator components and laser systems.

The solution for satisfying these requirements are timing distribution systems based on fiber-optic transmission lines. These systems can provide femtosecond level synchronization between accelerator components and laser systems by taking advantage in optical communication technology and metrology. These transmission systems use ultra-low noise pulse trains from modelocked lasers as timing reference. The timing signals of the master oscillators are then transmitted via fiber-optic links to several remote end stations where the transmission delays are stabilized. Modelocked lasers or microwave oscillators are then tightly synchronized to end of the stabilized fiber links [1].

Timing distribution for telescope arrayAnother example for the application of fiber-optic timing distribution links are radio telescope arrays, where many antennas have to be synchronized for accurate telescope pointing, synchronization of processing instrumentation and online manipulation of observation data [2].

In general, optical clock distribution and synchronization will become more important in future. Technologies and applications such as ultraprecise navigation, gravitational sensing, coherent arrays or relativity experiments will require time comparison and synchronization over terrestrial fiber-optic links or satellite free-space links.

 


Menhir Photonics added values


Menhir Photonics offers modelocked lasers with the lowest phase-noise available on the market today combined with extreme reliability. Fig. 1 shows a typical phase noise measurement for a free-running laser of the MENHIR-1550 series, measured on the 10 GHz carrier i.e. the 40th harmonics (250 MHz pulse repetition rate). Note that the noise floor of the measurement limits the integrated timing jitter to approximately 500 as (attoseconds).

Fig 1.: 1) Phase noise power spectrum of a free-running MENHIR-1550 250MHz laser measured at the 10 GHz harmonics. 2) Integrated timing jitter starting at 10 MHz for the same free-running laser.

All lasers of the MENHIR-1550 SERIES have an optional fast repetition rate tuning with a modulation bandwidth of >50 kHz for repetition rate locking or synchronization. In addition, there is also the option for fast modulation of the pump current.

The MENHIR-1550 SERIES reaches unmatched levels of industrial quality and environmental stability. It has been excessively tested for vibrations, shocks and other external disturbances (space and aerospace related standard tests). For integration into space-critical applications, customized small-sized versions are available.

[1] Xin, M., Safak, K., Peng, M. Y., Kalaydzhyan, A., Wang, W., Mücke, O. D., Kärtner, F. X., “Attosecond precision multi-kilometer laser-microwave network”, Light Sci. Appl. 6, e16187 (2017)

[2] Cliche, J.-F. & Shillue, B. “Precision timing control for radioastronomy: maintaining femtosecond synchronization in the Atacama Large Millimeter Array”, IEEE Control Syst. 26, 19–26 (2006)