Investigation of Transients in Single-Fiber Bidirectional Closed-Loop WDM Ring Network Using High-Power Gain Clamped EDWA

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 gen- erate 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-sil- icon 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 per- formance operate with signals entering together from both ends or even from opposite ends. The gain properties of the amplifier are almost perfectly symmetric.