Determination of the thermal loading in laser-diode-pumped erbium-ytterbium-codoped phosphate glass microchip laser

The fractional thermal loading in a laser-diode-pumped erbium-ytterbium-codoped phosphate glass microchip laser is an important parameter. We have developed two methods to determine the fractional thermal loading when the laser is operating on fundamental mode. By measuring far-field divergence angles, the thermal focal length and the fractional thermal loading of a microchip TEM00 laser with a short cavity length can be calculated. The fractional thermal loading is also obtained through numerical calculations of rate equations with the consideration of upconversion processes. The results of these two methods are in good agreement. (c) 2007 Optical Society of America.