Compact system for high-speed velocimetry using heterodyne techniques

We have built a high-speed velocimeter that has proven to be compact, simple to operate, and fairly inexpensive. This diagnostic is assembled using off-the-shelf components developed for the telecommunications industry. The main components are fiber lasers, high-bandwidth high-sample-rate digitizers, and fiber optic circulators. The laser is a 2W cw fiber laser operating at 1550nm. The digitizers have 8GHz bandwidth and can digitize four channels simultaneously at 20GS∕s. The maximum velocity of this system is ∼5000m∕s and is limited by the bandwidth of the electrical components. For most applications, the recorded beat frequency is analyzed using Fourier transform methods, which determine the time response of…

• UD
  U.S. Department of Energy
• VG
  Vedecká Grantová Agentúra MŠVVaŠ SR a SAV
• LL
  Lawrence Livermore National Laboratory