Fiber optic two-color vibration compensated interferometer for plasma density measurements

A fiber optic, heterodyne, two-color interferometer utilizing wavelength division multiplexing technology has been developed for measuring electron density in plasmas. Vibration compensation is accomplished via common path 1.31 and 1.55 mu m distributed feedback laser interferometers. All beam combining, splitting, frequency modulation, and collimation are accomplished by shared single-mode fiber optic components. Measurements of an argon radio-frequency generated plasma with electron densities of 10(20) m(-3) show effective vibration compensation and typical line-density resolution of approximately 2x10(19) m(-2). (c) 2006 American Institute of Physics.