For its part, Sumitomo Electric has now developed a coupled-core MCF (CC-MCF) including 4 pure-silica cores in the standard 125-µm cladding. The developed fiber has achieved the attenuation of 0.158 dB/km at the wavelength of 1550 nm and the spatial mode dispersion (SMD) of 6.1 ps/√km in the wavelength from 1520 to 1580 nm, both of which are the lowest ever reported in the optical fibers for space division multiplexing, contends the company.