P.J. Suni

An Ytterbium-doped Monomode Fibre Laser: Broadly Tunable Operation from 1·010 μm to 1·162 μm and Three-level Operation at 974 Nm

Abstract Continuous-wave laser action has been observed from an ytterbium-doped monomode fibre laser on the three-level transition at 974 nm and on the four-level transition at 1036 nm with slope efficiencies of 67% and 77% respectively, with respect to absorbed power. Tuning behaviour is described, in which polarisation control by means of fibre loops has allowed smooth continuous tuning from 1·010 μm to 1·162 μm.

Measurements of fibre laser losses via relaxation oscillations

Abstract We describe a simple method for measuring fibre laser losses. The method is based on including relaxation oscillations by modulating the laser gain. From the oscillation frequency and known fibre parameters a loss figure can be extracted. Loss measurements performed on a Nd-doped fibre laser are presented.

Efficient superfluorescent emission at 974 nm and 1040 nm from an Yb-doped fiber

Abstract End-pumping of an Yb-doped single-mode fiber has yielded > 10mW and 30 mW of broadband superflourescence at 974 nm and 1040 nm, respectively. Slope efficiencies > 40% have been obtained. Pump wavelength dependent linewidths between 2 nm and 19 nm have been observed.

Thermal Considerations In Longitudinally Pumped Fibre And Miniature Bulk Lasers

Estimates are made of conditions under which longitudinally pumped lasers, fibre lasers in particular, will show noticeable thermal effects due to heating induced by the pumping process.

Lasing Characteristics Of Ytterbium, Thulium And Other Rare-Earth Doped Silica Based Fibers

We have experimentally studied the lasing characteristics of silica fibers doped with Yb, Tm, Pr and Ho and present a summary of these results.

Actively Mode-Locked Fiber Lasers

We review recent investigation into the active mode-locking of rare earth doped silica, monomode fiber lasers. Dopants include Nd3+, Er3+ and Yb3+:Er3+ and mode-locking has been accomplished either by amplitude modulation or by phase modulation. Both bulk optic and integrated optic modulators have been used. Pulses of 4 psec duration have been observed in an Er3+-doped fiber laser with an integrated amplitude modulator. 20 psec pulses have been produced from a Nd3-doped fiber laser with a bulk phase modulator. In both these systems, the introduction of anomalous group velocity dispersion compensates for self-phase modulation, resulting in bandwidth-limited operation. The paper concentrates mainly on three experiments involving the mode-locking of fiber lasers by active phase modulation. A bulk LiNb03 phase modulator produces pulses of 20 psec and 37 psec respectively in Nd3-doped and Yb3:Er3-doped fiber lasers. The third system incorporates intra-fiber phase modulation. This allows considerable simplification of the laser cavity, resulting in a diode-pumpable source of 80 psec mode-locked pulses with a threshold pump power of 520 pW and a slope efficiency of 48%.