Mode locking and Q-switching of a neodymium doped monomode fibre laser

Abstract

A cw Nd-doped monomode fibre laser has been actively mode-locked and Q-switched at 1.08µm and 0.906µm. Subnanosecond mode-locked pulses of ~20 pJ and Q-switched pulses of 200 nsec and ~10W peak power are observed at 1.08µm. There has been much recent interest in laser systems using as the gain medium rare earth-doped optical fibres which only support a single waveguide mode at the lasing wavelength. The small diameter of the active region, i.e. the fibre core, combined with longitudinal pumping by a laser allows the achievement of low thresholds, high conversion efficiencies and high gain. The small core diameter also eliminates the thermal distortion and thermal birefringence problems that plague bulk glass systems. As an illustration of these benefits of a fibre laser, we note that cw operation has been achieved, with low threshold, even for three-level laser schemes. Thus Er doped fibre, operating at 1.55µm, (⁴ I _13/2 to ⁴ I _15/2) has been operated as a cw laser and cw operation of a Nd-doped fibre has been achieved on the ⁴F_3/2 to ⁴ I _9/2 transition at ~0.9µm. Neither of these transitions has been operated at room temperature in a bulk glass-laser with continuous-wave output.

More information

Identifiers

Catalogue record

Export record