End-pumped double-clad waveguide laser

Summary form only given. The use of a double-clad guiding structure to allow efficient pumping by non-diffraction-limited high-power diodes, and yet still obtain diffraction-limited laser output, has been extensively studied in optical fibres. Recently, a one-dimensional version of this technique has been applied to planar waveguides, allowing the development of very compact, proximity-coupled, diode-bar side-pumped waveguide lasers. CW powers of >10 W have been obtained in this way but, with the use of a monolithic plane/plane cavity, the output is still highly non-diffraction-limited in the non-guided direction. We investigate the use of similar double-clad structures end-pumped by a 4 W broad-stripe diode obtaining >1 W in a beam with measured M/sup 2/ values of 1.0 by 1.8.