Laser characteristics at 1535 nm and thermal effects of an Er:Yb phosphate glass microchip pumped by Ti:sapphire laser

An Er:Yb codoped phosphate glass microchip laser has been studied under pumping with a Ti:sapphire laser ranging from 945 to 990 nm. The characteristics (threshold, slope efficiency) are first described for an optimized laser. The gain spectrum is calculated for the transition I-4(13/2) --> I-4(15/2) around 1535 nm from fundamental spectroscopic data and from experimental results. Red-shift effect on the frequency of a single mode is experimentally observed when the pump power is increased, originating from thermal effects. Temperature inside the microchip cavity and thermal expansion coefficient were determined by employing the intensity ratio of two green upconversion emission line centered at 530 and 554 nm, respectively, which quantitatively explain this red shift. (C) 2002 Elsevier Science B.V. All rights reserved.