A bidirectional amplification module has been proposed for use in IP-over-CWDM networks. The module is based on a bidirectional erbium-doped fiber amplifier. The loss compensation characteristics of the module obtained in a bidirectional IP transmission experiment confirmed that the losses of the optical node and the transmission fiber in the network can be compensated for effectively by the module making it possible to increase the number of nodes and the total fiber length of the network.