Sumitomo Electric Has Developed Coupled Multi-Core Optical Fiber Suitable for Ultra-Long-Haul Transmission
March 25, 2016
Sumitomo Electric Industries, Ltd.
Sumitomo Electric Industries, Ltd. has developed a new-type coupled multi-core optical fiber suitable for ultra-long-haul transmission, which has set new records of the low attenuation and the low spatial mode dispersion in the optical fibers for space division multiplexing.
The data network traffic in the long-haul transmission systems is growing due to the widespread uses of smartphones, data centers, and others; and the transmission capacity has been improved with the low-loss*single-mode fibers* . At the same time, to realize the drastic improvement of the capacity, space-division multiplexing (SDM) has been intensively studied, and the multi-core fiber (MCF)* is expected as a next-generation optical fiber that can realize ultra-high-capacity transmission systems.
Sumitomo Electric has developed a coupled-core MCF (CC-MCF)*
The ultra-low attenuation approaching that of the commercial ultra-low-loss single-mode fiber (SMF) enables signal transmission with lower noises than the previously-reported SDM fibers, and is expected to realize the spatial channel count increase without per-channel capacity degradation. The SMD of 6.1 ps/√km is one fifth the lowest SMD of the previously reported SDM fibers, and thus can reduce the calculation complexity of the multiple-input-multiple-output (MIMO) digital signal processing (DSP)* for the crosstalk compensation. Furthermore, the developed CC-MCF with the standard 125-µm-diameter cladding can be cabled with the existing cable designs for the standard optical fibers, and is expected to have the high mechanical reliability equivalent to that of the standard optical fiber.
Sumitomo Electric has produced many pioneering results*in the research and development on the MCF since 2009. Since 1980's, it also has been developing and manufacturing the pure-silica-core fibers, and contributing to the developments of the submarine optical cable networks* . The present achievement has been made by integrating these technologies.
Sumitomo Electric will continue the developments of various MCFs and related-technologies for their practical application.
These results will be presented at a postdeadline paper*session (6:00 pm on March 24, 2016, PDT) of Optical Fiber Communication Conference (OFC 2016, March 20-24, 2016, Anaheim, California, USA), one of the largest conferences on optical fiber communications.
|Single-mode fiber (SMF)||An optical fiber that has a thin (<10 µm) core. Only one optical path exists in the fiber.|
|Standard optical fibers||Optical fibers standardized for various fiber optic communications including the SMF. The standard cladding (glass) diameter is 125 µm.|
|Multi-core fiber (MCF)||An optical fiber that has multiple cores. There are "uncoupled" type and "coupled" type.|
|Uncoupled MCF||An MCF that has the core-to-core crosstalk low enough for using each core as an isolated spatial channel. For the crosstalk suppression, the core-to-core distance has to be separated and the cladding diameter tends to become large.|
|Coupled MCF /
coupled-core MCF (CC-MCF)
|An MCF that has short core-to-core distance and large crosstalk. The MIMO DSP is necessary for crosstalk compensation, but the CC-MCF can pack more cores in a smaller cladding than the uncoupled MCF.|
|Multimode fiber (MMF)||An optical fiber that has a thick (>10 µm) core. Multiple optical paths (modes) exist in the core. The modal crosstalk is difficult to suppress and thus the MIMO DSP is necessary for crosstalk compensation in the SDM transmission.|