OPTICAL AMPLIFIER AND LASER

摘要

A laser has a resonant cavity defined by a pair of mirros (3, 5) butted to respective ends of a fluorozirconate optical fibre (1). The fibre (1) has a numerical aperture of 0.205 and an LP11 mode cut-off of about 2. 0 mu m. The fibre (1) is co-doped with thulium ions to a concentration of about 0.1%, and with terbium ions to a concentration of about 1 %. An optical pump source (6) provides a pump signal at 775 nm which excites the thulium ions into the <1>G4, energy level to provide lasing at about 475 nm. The pump source is preferably a high power semiconductor laser (16).