Silicate and phosphate glass waveguide amplifiers doped with Er3+, and codoped with Er3+/Yb3+ are theoretically studied. Configurations for core and core-cladding doped waveguide amplifiers are considered. It is shown that gain in the core-cladding doped amplifiers is considerably higher than core doped amplifiers. It is also shown that with input signal power up to 1 mW and 200 mW pump power, a 12.5 dB gain can be achieved in a 3 cm long waveguide amplifier, with a noise figure of 3.05 dB.