Duplex Optical Amplifier for 10 Gb/s Ethernet Link over 120 km SSMF and 15 km DCF

This paper focuses on extending the maximum link distance between typical optical transceivers in mobile aggregation networks. Our duplex optical amplifier is inserted between base-stations in suburban or border areas, in order to amplify 10 Gigabit Ethernet data transmitted in C-band wavelength (1530 - 1565 nm). It consists of two Conventional Erbium-Doped Fiber Amplifiers (C-EDFAs), each for unidirectional transmission. It can support 4G Long-Term Evolution (LTE)/5G network application at 10 Gb/s and higher bit-rates. The measured parameters of duplex optical amplifier are operating wavelength range, amplifier gain, and noise figure (NF). Their operating ranges of both C-EDFAs are from 1530 nm to 1562 nm. Their maximum gains are approximately 24.5 dB at 0.2-Ampere pump current and 1550-nm input wavelength. Their NFs are below 6.3 dB at -3 dBm input power and 1550-nm input wavelength. In addition, we measured a Burst-Mode EDFA (BM-EDFA) to compare with C-EDFAs. The BM-EDFA's operating range is from 1537 to 1561 nm. Its maximum gains are approximately 24.5 dB and 31 dB at pump current of 0.175 Ampere and 0.38 Ampere respectively. Its NF is below 6 dB at the same input power and wavelength as in C-EDFAs. From these parameter results, the characteristics of C-EDFA and BM-EDFA are likely the same. However, from 10 Gb/s data transmission experiment, BM-EDFA has the lowest power variation on Ethernet packets, compared to duplex C-EDFA and another commercial EDFA. Furthermore, the effects of EDFA noises and Chromatic Dispersion (CD) over a link's performance has been investigated and shown by Bit Error Rate (BER) measurements. The Dispersion Compensation Fiber (DCF) and 1-nm Tunable Optical Band-Pass Filter (TOBPF) were added after C-EDFAs, to reduce CD and noises respectively. Finally, the data transmission over 120 Km Standard Single-Mode Fiber (SSMF) & 15 Km DCF by using duplex optical amplifier at 10 Gb/s bit-rate was achieved with 0.5-dB power penalty at 10(-9) BER. Moreover, we can identify that BM-EDFA is more suitable for Ethernet link than C-EDFAs. Hence, we propose that C-EDFAs in duplex optical amplifier should be replaced by BM-EDFA to improve the link performance.