A novel technique for active fibre production

Active fibre devices are conventionally manufactured using MCVD technique. Recently it has been shown that nearly equivalent results can also be obtained with sol–gel technology. Now we present a novel technique allowing simplification of the manufacturing process even more. The required constituents are mixed in the form of dry micro- and nano-sized particles. A silica glass tube forming the future core region of a fibre preform is filled with a powder mix of SiO2, 1% Nd (as Nd2O3) and 10% Al (as Al2O3). This tube is mounted in the centre of a larger tube forming the future cladding. The empty space between the two tubes is filled with SiO2 powder. After preheating, the evacuated preform is drawn to a fibre. A length of 45 cm, cladding-pumped with a diode laser at 808 nm as well as a core-pumped fibre of 5.1 cm length showed laser action between 1.05 and 1.1 μm.