BIDIRECTIONAL TRANSMISSION AT 622 MB/S UTILIZING ERBIUM-DOPED FIBER AMPLIFIERS

Amplification of two bidirectional 622 Mb / s optical signals is demonstrated using a single erbium-doped fiber amplifier. Bidirectional amplification is examined with the EDFA operating as a midspan repeater and as a pre / post amplifier at one terminal end of a 95 km fiber span. Without using any isolators in the EDFA, bidirectional optical amplification through a single EDFA is achieved while simultaneously improving system gain relative to an unidirectional link without an EDFA. The system gain improvement is 9.5 and 7 dB in the pre / post configuration and 25.5 and 20.3 dB in the midspan configuration when the signal wavelengths are 1537 and 1545 nm, respectively.