Patent ID: 7269349

Claim:
A single-wire bi-directional transmission device, comprising: an optical-fiber transmission-line on which a first signal light is transmitted in a first transmission direction from one input/output terminal toward the other input/output terminal, and a second signal light with a different wavelength from that of the first signal light is transmitted in a second transmission direction opposite to the first transmission direction; a first Raman pump light source which generates a first Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the first signal light, but not having a Raman gain-bandwidth for amplifying the second signal light; a first injection unit which injects the first Raman pump light from either of said one input/output terminal, or said other input/output terminal into said optical-fiber transmission-line; a second Raman pump light source which generates a second Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the second signal light, but not having a Raman gain-bandwidth for amplifying the first signal light; a second injection unit which injects the second Raman pump light from the other one of either of said one input/output terminal, or said other input/output terminal into said optical-fiber transmission-line; a first optical transmitting unit that includes a plurality of transmitters which generate first signal lights with different wavelengths, respectively, in a first wavelength band; a second optical transmitting unit that includes a plurality of transmitters which generate second signal lights with differents wavelengths, respectively, in a second wavelength band having a different frequency band from that of the first wavelength band; a first optical receiving unit that includes a plurality of receivers which receives the first signal lights; a second optical receiving unit that includes a plurality of receivers which receives the second signal lights; a first error-rate monitoring unit that measures an error rate of received signals output respectively from the plurality of receivers in the first optical receiving unit; a second error-rate monitoring unit that measures an error rate of received signals output respectively from the plurality of receivers in the second optical receiving unit; a first transmitting unit control unit which controls the first optical transmitting unit so that the transmitting level of the first optical transmitting unit is increased or decreased based on monitored results from the first error-rate monitoring unit; and a second transmitting-unit control unit which controls the second optical transmitting unit so that the level of the second is increased or decreased based on monitored results from the first error-rate monitoring unit.