Optical repeater having redundancy

An optical repeater having a first optical amplifier for a first optical fiber transmission line and a second optical amplifier for a second optical fiber transmission line. Each of the first and second optical amplifiers has a doped fiber doped with a rare earth element, a pumping light source for outputting pumping light, a supplying optical coupler for supplying the pumping light to the doped fiber, and an extracting optical coupler for extracting the pumping light. Each extracting optical coupler has an exchange port for outputting a part of the pumping light remaining in the corresponding doped fiber after pumping. The optical repeater further has an optical fiber for connecting the exchange ports in the first and second optical amplifiers to exchange the pumping light. With this configuration, even if one of the pumping light sources has failed, the pumping light from the other pumping light source is supplied to both doped fibers, thereby making the optical repeater have redundancy.