A short 10 W cw neodymium-doped M-profile fiber laser

were determined to be 1.530 and 1.000 pm, respectively. Figure 1 depicts the variation of the internal gain with output signal power. Figure 2 illustrates how the noise factor varies with the output signal power. The optimum length for the waveguide amplifier was 6 mm. Figure 3 shows the variation of the internal gain and noise factor with the pump power for the 6-mm-long waveguide. A record internal gain of 19.5 dB with 50-mW pump power (18 mW injected in the waveguide) was achieved in the 6-mm-long waveguide. This is much higher than the previously reported gain in silver ion-exchanged waveguide.'J We attribute the improvement to the low propagation losses in our waveguide and the use of optimum waveguide length. Themistry Department, McGill University, Montreal, Quebec, H3A 2K6, Canada