Sumitomo Electric Industries, Ltd. (Osaka, Japan) has developed a new type of coupled multi-core optical fiber suitable for ultra-long-haul transmission, which the company says has set new records for low attenuation*1 and the low spatial mode dispersion*2 in optical fibers for space division multiplexing.
The company maintains that data network traffic in long-haul transmission systems is growing due to the widespread uses of smartphones, data centers, and other applications; and that transmission capacity has been improved with the use of low-loss single-mode fibers. At the same time, to realize such drastic improvements in capacity, space-division multiplexing (SDM) has been intensively studied, and multi-core fiber (MCF) is expected as a next-generation optical fiber that can realize ultra-high-capacity transmission systems.
*2: Spatial mode dispersion (SMD) is the amount of the time spread of the light pulse, induced by the optical path differences between multiple optical paths in an optical fiber. The lower SMD is preferable because the DSP calculation complexity can be reduced.
*3: Multiple-input-multiple-output (MIMO) digital signal processing (DSP) is the digital calculation that can compensate the crosstalk of the MCF and the MMF. Fully mixed signals can be untangled to the original individual signals.