GAIN CHARACTERISTICS OF A HIGH-CONCENTRATION ER3-DOPED PHOSPHATE-GLASS WAVE-GUIDE()

A channel waveguide on an erbium-doped phosphate laser glass was fabri cated by a dry silver-film ion exchange technique, and its gain proper ties were studied experimentally. The propagation loss of the fabricat ed waveguide was 0.63 dB/cm at 1.3 mu m. Er3+ concentration of 1x10(20 ) ions/cm(3) was chosen so that no concentration quenching occurred. T his was confirmed by measuring a fluorescence lifetime of 8.4 ms at 1. 54 mu m. Gain of the fabricated waveguide was measured by using a Ti:s apphire laser at a wavelength of 980 nm and a laser diode of 1.552 mu m producing pump and signal beams, respectively. The signal wavelength used for the experiments was shorter than the emission peak, and the measured gain of the 1.8 cm waveguide was comparable to the total loss . However, the model showed that lasing is expected at the emission pe ak with a 3.6 cm long waveguide fabricated in a similar manner. Calcul ation results showed that the potential gain of 8.8 dB can be realized with 250 mW pump power, and a 7.2 cm long waveguide provided that mod e overlap can be increased by 20% and propagation loss can be reduced by 50%. No significant upconversion effect was observed up to 1.1X10(6 ) W/cm(2) pump intensity. (C) 1995 American Institute of Physics.