We investigate a transparent WDM ring network design immune to accumulated power transients where simultaneous bidirectional operation is achieved on a single fiber. This allows cost effectiveness, flexible traffic re-routing, and network operation. We demonstrate that add/drop of 15 out of 16 channels generate negligible (< 0.15 dB) power excursion on the surviving channel. These results have been obtained by using new high-gain erbium-doped waveguide amplifiers in an innovative gain-clamped configuration that allows bidirectional operation. The glass-on-silicon waveguide optical amplifiers are able to achieve a clamped flat gain of 15 dB on full C-band with up to 0-dBm input power. This is the highest output power ever reported for an erbium-doped waveguide amplifier. The amplifier can with almost identical performance operate with signals entering together from both ends or even from opposite ends. The gain properties of the amplifier are almost perfectly symmetric.