Gain-clamping in two-stage L-band EDFA using an unwanted backward ase from second stage

• Main Authors: Harun, Sulaiman Wadi, Ahmad, Harith
• Format: Article
• Published: Elsevier 2003
• Subjects: Q Science (General); QC Physics; TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.um.edu.my/19641/; http://dx.doi.org/10.1016/S0030-3992(03)00049-5
• Institution: Universiti Malaya

A gain clamping technique for the long wavelength band erbium-doped fiber amplifier (L-band EDFA) is presented. It uses two circulators and a broad band fiber Bragg grating to route wasted backward C-band ASE from the second stage and launch it back into the input end of the first stage of a two-stage amplifier. The two-stage L-band EDFA has shown a small signal gain improvement of 5.7 dB compared to a single-stage amplifier with a slight noise figure degradation. By utilizing the wasted backward ASE, a L-band gain-clamped EDFA with high gain can be realized. Compared to the unclamped case, this gain-clamping technique is effective in reducing the total gain variation as small as 0.3 dB.