By using a thick-walled SiO2 tube (25-mm outside diameter, 1-mm inside diameter), a soft-glass core containing Nd or Yb–Er has its alkali (and to a lesser extent its alkaline earth) components volatilized during drawing to give a good-quality laser fiber with Nd- or Yb–Er-doped cores.
© 1989 Optical Society of America
Original Manuscript: December 22, 1988
Manuscript Accepted: May 3, 1989
Published: July 15, 1989
E. Snitzer and R. Tumminelli, "SiO2-clad fibers with selectively volatilized soft-glass cores," Opt. Lett. 14, 757-759 (1989)