Wide band optical amplifier

Abstract

The present invention discloses a wide band optical amplifier with a common mid-stage device. In the wide band optical amplifier according to the present invention, the signals that enter the amplifier are first split into a couple of sub-band signals. The sub-band signals are amplified independently at different optical amplification sections, but they share a common mid-stage device, which reduces the complexity and the cost of the amplifier. The sub-band signals propagate count-directionally in the common mid-stages device to reduce the nonlinear interactions between the signals in different sub-bands. A wide band optical amplifier incorporating a common mid-stage device with directionality is also disclosed.