Abstract

Q-switched fibre lasers offer a simple and robust means for the generation of high energy, nanosecond pulses at eye safe wavelengths around 1550nm suitable for a number of industrial, sensing and nonlinear optics applications. Unfortunately, Q-switched fibre lasers based on conventional erbium doped fibre designs are limited to <10 µJ pulse energies by rapid energy loss in the form of amplified spontaneous emission during the gain recovery stage due to the high gain-efficiency of the fibres. Recently we showed that considerably higher pulse energies (180 µJ) can be achieved simply by increasing the mode field diameter (MFD) of the fibre and thereby compromising the gain efficiency of the system[1]. The increased MFD also improves the nonlinear and power handling characteristics of the fibre.

© 1998 IEEE