Development of bismuth doped silica fibres for high power sources amp; long wavelength generation from ytterbium doped fibre lasers

摘要

A detailed study of fabrication and characterisation of bismuth (Bi) doped silica optical fibre has been investigated. Three different fibre fabrication techniques were applied to study the possible influence on Bi-luminescence: modified chemical vapour deposition (MCVD) and the solution doping technique, MCVD chemical-in-crucible deposition technique and the powder-in-tube (PIT) technique. Spectroscopic absorption and Bi luminescence and fluorescence decay properties under different pumping wavelengths and with different host glass compositions are presented and provide important information for device applications. The influence of unsaturable loss on laser performance is investigated. The feasibility of direct laser diode pumping of Bi-doped fibre lasers at the wavelengths of 915 and 975 nm was examined by measuring excited state absorption in Bi-doped silicate fibres for the wavelength range of 900 -1300 nm. Enhancement in spectroscopic properties of Bi-doped fibre, by H2-loading, has been examined.Bi-doped fibre laser operating in the wavelength region of 1160-1179 nm has been demonstrated. The fibre laser performance at 1179 nm was investigated incorporating different cooling arrangements. The operation of Bi-doped fibre amplifier at 1179 nm, in both low and high input signal regime, was also examined. An all-fibre, narrow-linewidth, high power Yb-doped silica fibre laser at 1179 nm has been demonstrated. Furthermore, theoretical work confirms that the proposed laser architecture can be easily scaled to higher power.