Optimized Nonregenerative Repeater Using Cascaded Erbium-Doped and Raman Fiber Amplifier

Abstract

Fiber-based optical amplifiers such as the erbium-doped fiber amplifier (EDFA) and Raman fiber amplifier (RFA) offer the attraction of high gain, low coupling loss and polarization insensitivity. Hence their use in combination to form a nonregenerative repeater (NRR) deserves consideration. This paper provides a theoretical analysis and gain optimization for this form of NRR. This arrangement is found to provide higher gain than either an EDFA or a RFA repeater alone and offer the potential of extending the NRR span to over 300 km.