Abstract

One of the strong present interests is to produce high power laser radiation in the 1.9 μm region of the spectrum in order to satisfy a number of important medical applications such as surgery. Utilising the double-clad pumping geometry [1] in conjunction with diode-pumping allows one to generate conveniently high power laser radiation of both high efficiency and high beam quality. In addition, quasi-three level transitions such as the ³H₄→³H₆ laser transition of Tm³⁺ benefit greatly from the high level of pump and laser field confinement reletant to fibre lasers, which enables transitions that inherently have a relatively small stimulated emission cross section coupled with a possible large ground state reabsorption loss, to lase efficiently. Judicious design of the double-clad fibre is therefore required in order to extract the maximum output power and efficiency.

© 1998 IEEE