We propose a repeated bidirectional WDM transmission system using cascaded WDM MUX/DMUX pairs as narrow-bandpass filters and reflection attenuators. Fiber span is increased by inserting unidirectional EDFAs between WDM MUX/DMUX pair as in-line amplifiers. A three-channel hybrid system with one 10-Gb/s and two 2.5-Gb/s channels is also demonstrated In the 1550-nm region for transmission over 150 km of dispersion-shifted fiber. Negligible power penalty due to back reflection was observed.