National Physical Laboratory

Beat Frequency Monitoring System

Beat System
Beat frequency monitoring systems
of a stabilised laser against an
NPL iodine stabilised laser

NPL beat frequency monitoring systems can be used for:

  • Calibration of stabilised laser sources used in precision length metrology and spectroscopy
  • Intercomparison and characterisation of iodine stabilised reference lasers
  • Assessment of laser frequency stability of industrial stabilised lasers

The NPL hardware system comprises:

  • Fully adjustable and demountable beam combining optics to cope with currently available Industrial stabilised lasers and stabilised laser interferometers
  • Fast photodetection, RF amplification and low noise filtering with beat detection bandwidths up to 800 MHz
  • 1 GHz frequency counter with IEEE interface
  • 1 GHz RF spectrum analyser available on request
  • Custom options available on request

NPL beat frequency software for PCs:

  • Absolute frequency and drift measurement of stabilised lasers over several hours
  • Beat frequency two sample (Allan variance) measurements


Customer Service tel: +44 20 8943 6796

Last Updated: 12 Jul 2016
Created: 11 Aug 2007


Please note that the information will not be divulged to third parties, or used without your permission