To achieve high-gain S-band waveguide amplifiers with integrated configuration, S-, U-, and F-bend waveguides based on Tm3+-doped germanate glasses have been designed in an 8 cm×6 cm substrate. Using simulated-bend method, the optimal radius for the curved structure is offered to be 1.90 cm with loss coefficient of 0.04 dB/cm. For the F-bend waveguide, the internal gain at 1482 nm is derived to be 13.01 dB, which is higher than the values of 8.21 and 4.22 dB in the U-and S-bend waveguides, respectively, and nearly three times higher than that of the straight one (3.84 dB). Simulation results indicate that the reasonable optical path design can considerably enhance the optical gain in Tm3+-doped germanate glass channel waveguides.