Pump Light Source for Distributed Raman Amplification in MCFs With LD Sharing Circuit

We report an integrated pump source for distributed Raman amplification (DRA) in multicore fiber (MCF) where the MCF cores share pump laser diodes (LDs). The DRA requires many LDs and passive components if it is to obtain a flat and polarization-insensitive gain spectrum, especially in MCF transmission. To reduce the number of optical components, we propose a pump configuration where two cores share a pump LD set. The number of LDs is reduced almost by half. We integrate passive components, such as wavelength division multiplexers and polarization beam combiners, in a planar lightwave circuit to realize the LD sharing circuit. With our proposed pump sharing configuration, we obtain a DRA gain of more than 5.7 dB over the entire C-band in an MCF.