Remote optically pumped amplifier ROPA
The use of ROPAs makes it possible to increase the distance between two network nodes. The ROPA is an erbium-doped fiber amplifier that is pumped remotely using wavelength 1480 nm either in working fiber or in an additional fiber. The device consists of two functional units: a passive unit (hermetically sealed box with a fiber-optic circuit) and an active unit (one or two pumping lasers). Two types of ROPA configuration are used: with a backward pumping (i.e. the pumping is provided from the receiver side) and with a forward pumping (i.e. the pumping is provided from the transmitter side). Working modes of amplifiers and the gain in distance can vary in different configurations, and depend on the required link capacity.