Improvements To A High-Frequency Fiber-Optic System For Plasma Diagnostics

A system for high-frequency recording of plasma diagnostics has previously been reported. Substantial improvements have been made in the system response, dynamic range, and calibration of the system. Plastic-clad silica fiber is used as a radiation-to-light converter using the Cerenkov process. A spectral equalizer device is used to compensate for the material dispersion in the fiber, increasing the frequency response (,1 GHz-km) and the dynamic range (a factor of >20 over a FWHM 1 nm, 50% transmitting interference filter). The calibration system uses a pulsed injection laser diode (<100 ps FWHM) injected into the fiber at the radiation end of the fiber and detected by a microchannel plate photomultiplier tube on the recording end. The injection laser diode is triggered by a synchronous trigger delay unit, which also triggers a sampling or real time scope after as much as 10 μs delay with <50 ps jitter. The system improvements will be desribed in more detail and the utility of these components in other plasma diagnostic systems will be discussed.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.