High-sensitivity two-stage erbium-doped fiber preamplifier at 10 Gb/s

An optical preamplifier with a record sensitivity of -38.8 dBm (102 photons/bit) at 10 Gb/s has been demonstrated. When the amplifier is employed in a practical link without an input isolator, the sensitivity is only slightly degraded to -37.6 dBm (135 photons/bit) by input coupling losses and feedback due to Rayleigh backscattering in the transmission fiber. It is predicted that this penalty can be reduced to 0.15 dB with an improved isolator in the composite EDFA.<
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