An optical amplifier for metro WDM networks, based on a gain-clamped semiconductor optical amplifier is proposed. The amplifier (RAGCSOA) consists of a low gain Raman fiber amplifier and a gain-clamped semiconductor optical amplifier. The RAGCSOA has over 20 dB gain and a noise figure below 3 dB. In addition, the potentially compact amplifier shows negligible transients under dynamic add-drops. Sixteen channels of 10 Gb/s signals were successfully transmitted over five NZDSF spans of 80 km using RAGCSOAs. RAGCSOAs were also used to successfully transmit sixteen channels of 10 Gb/s WDM signals over four 40km spans of SMF with add-drops. No penalty was observed when 15 out of 16 channels were dynamically add/dropped in all the transmission systems. The RAGCSOA can be very compact when a GCSOA chip and a Raman pump LD chip are packaged in a module.