The high-power side-pumped operation of a double-clad Tm:YAG waveguide lase
r at 2.02 mum, using two proximity-coupled 20W diode pump lasers, is report
ed. A slope efficiency of 43% was observed with respect to incident diode p
ower, giving a maximum output power of 15W. The double-clad geometry ensure
s diffraction-limited output in the guided plane.