Bi-doped optical fibers: a new active medium for NIR lasers and amplifiers

Abstract

Bi-doped glass optical fibers are a very promising active laser medium. Luminescence of Bi-doped glasses takes place in a spectral region of 1100-1500 nm [2], where no fiber lasers (or any other efficient lasers) exist. The glasses have very broad luminescence bands (200-400 nm) and long lifetime (200-700 μs). The Bi absorption bands are situated in a spectral region of 500-1100 nm where long-lived high-brightness laser diodes developed for the pumping of lasers and amplifiers are available. Besides, strong luminescence has been observed in a variety of glass compositions. However, up to 2005 there had been no reports on the fabrication of Bi-doped optical fibers. The first Bi-doped optical fibers were fabricated in 2005 [5,6] and that year the first Bi-doped fiber laser was constructed [7]. In this paper the recent results on the new laser material - Bi-doped glasses and optical fibers are reviewed. First, luminescence properties of various Bi-doped glasses are discussed. Then we describe the Bi-doped silica-based optical fiber fabrication by MCVD technique and the absorption and luminescence properties of the fibers. At last the results of investigations of high-power Bi-doped fiber lasers are presented.