73.6km Attenuation Free Concatenated Fibers Doped with Distributed Erbium

Abstract

Recently, distributed Er-doped fiber amplifiers have become of great interest.1)-5) Intrinsic fiber loss can be compensated by the distributed gain. As a result, a fiber which is free from the attenuation can be realized.2) Due to its small gain, the distributed EDFA also has the advantage of low amplified spontaneous emission(ASE). Moreover, no isolator to prevent lasing is necessary, so bi-directional transmission is possible. This kind of fiber is also applicable to soliton transmission.5)