Think Outside the Fiber: Imaging Amplifier for Space-Multiplexed Optical Transmission

This paper proposes a simple and practical method to amplify signals for space-multiplexed optical transmission. In this amplification technique, the output facet of the multicore or multimode fiber is mapped back to the same type of fiber after passing through an imaging and bulk amplifying region. Simulations are carried out for a seven-core multicore fiber with the signal lasers amplified by a bulk erbium-ytterbium-doped phosphate glass amplifier. Amplifier gain of ~20 dB is achieved at an input power of 6 mW for each individual core with an optical power conversion efficiency of 32.5%. The proposed amplifier technique does not have a core or mode count limit for multicore and multimode fibers.