Single-Mode Neodymium Fibre Laser
Rare-earth doped single-mode optical fibres have been grown in the Department of Electronic and Information Engineering at Southampton using a modified chemical vapour deposition technique. The technique involves the introduction of the core material and dopants as volatile compounds. A prototype resonator has been constructed using a Nd3+ doped fibre as the active medium and microscope objectives to couple in and out of the fibre. The resonator can then be longitudinally pumped by appropriate optical sources. Initial tests have involved a c.w. Rhodamine GG dyelaser as the pump source. When the dye laser is tuned to a Nd3+ absorption band at around 595 nm, lasing action at 1.08µm can be observed, with a threshold corresponding to a few milliwatts of absorbed dye laser power.