A diode-pumped planar Er/Yb waveguide laser is demonstrated. The devic
e was fabricated by thallium exchange in a phosphorus-free silicate gl
ass. Lasing was achieved at 1544 nm with a threshold of 5 mW and a slo
pe efficiency of 2%. The low threshold indicates the absence of the se
vere backtransfer effects previously reported in Er/Yb bulk laser sili
cate glasses.