Optical system for compensating for signal loss

An optical system for compensating for signal loss, comprising:

• a transmission fiber to transmit a wavelength division multiplexing (WDM) input optical signal between a first point and a second point, the WDM input optical signal is 1550 nanometers (nm);
• a second order forward Raman pump module positioned along a first region of the transmission fiber proximate to the first point;
• and
• a first order backward Raman pump module positioned along a second region of the transmission fiber proximate to the second point,
• wherein the first order backward Raman pump module is configured to generate a first pumping light along the transmission fiber to amplify the WDM input optical signal at the second region of the transmission fiber, the first pumping light is 1455 nm,
• wherein the second order forward Raman pump module is configured to generate a second pumping light along the transmission fiber to amplify the first pumping light generated by the first order backward Raman pump module, the second pumping light is 1365 nm,
• wherein the amplified first pumping light amplifies the WDM input optical signal at the first region of the transmission fiber,
• wherein a direction of travel of the first pumping light is opposite to a direction of travel of the WDM input optical signal,
• wherein the direction of travel of the first pumping light is opposite to the direction of travel of the second pumping light.