| Presentation | 2023-01-13 Inter-core skew and mode-dependent loss degrade Q2 in long-haul coupled-core multicore fibre transmission Shohei Beppu, Daiki Soma, Noboru Yoshikane, Takehiro Tsuritani, |
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| PDF Download Page |  PDF download Page Link |
| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | To dramatically increase the transmission capacity of optical backbone network systems, space division multiplexing (SDM) transmission systems, in which multiple spatially different channels are utilized to distribute the transmission power, are attracting attention. According to Shannon's theorem, the total transmission capacity can be increased by increasing the number of SDM channels, as the transmission channel capacity only decreases with the logarithm of the transmission power. Coupled-core multi-core fibre (CC-MCF) transmission have attracted attention as SDM transmission systems that can achieve long-distance and massive SDM. The number of cores can be increased (e.g., 12 cores) and the effective area can be increased by compensating for crosstalk between cores using multiple-input multiple-output (MIMO) digital signal processing at the receiver. Moreover, CC-MCFs have low spatial mode dispersion (SMD), enabling MIMO equalization with low computational complexity. However, when an optical repeater is configured with a fan-in/fan-out (FIFO) device and multiple single-core EDFAs, excellent optical amplification performance is achieved, but an extra inter-core group delay difference, namely, skew, is generated. The skew increase effective SMD. If the SMD exceeds the tolerance of MIMO signal processing, Q2 degradation occurs. High-precision skew adjustment is therefore required. When the optical transponder is composed of a multi-core EDFA and a direct connection (e.g., fusion splice) to the transmission fiber, the skew problem can be avoided, but a large mode-dependent loss (MDL) is introduced. The non-orthogonal crosstalk between spatial modes caused by the MDL cannot be removed by the usual linear MIMO equalization, which causes a significant degradation in the Q2. However, the relationship between skew and MDL and Q2 has not been evaluated in detail. In this work, we experimentally investigate on the relationship between skew and MDL and the Q2 after long-haul transmission. It was found that an adjustment error of only 200 ps/span or less is required for skew to sufficiently suppress Q2. It was also found that the MDL not only causes a significant degradation of the average Q2, but also introduces time instability of Q2. |
| Keyword(in Japanese) | (See Japanese page) |
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| Paper # | OCS2022-65 |
| Date of Issue | 2023-01-05 (OCS) |
| Conference Information | |
| Committee | OCS / CS |
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| Conference Date | 2023/1/12(2days) |
| Place (in Japanese) | (See Japanese page) |
| Place (in English) | CANAL CITY HAKATA |
| Topics (in Japanese) | (See Japanese page) |
| Topics (in English) | |
| Chair | Takeshi Hoshida(Fujitsu) / Daisuke Umehara(Kyoto Inst. of Tech.) |
| Vice Chair | / Seiji Kozaki(Mitsubishi Electric) |
| Secretary | (NTT) / Seiji Kozaki(Sumitomo Electric Industries) |
| Assistant | / Hikaru Kawasaki(NICT) / Yuta Ida(Yamaguchi Univ.) |
| Paper Information | |
| Registration To | Technical Committee on Optical Communication Systems / Technical Committee on Communication Systems |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Inter-core skew and mode-dependent loss degrade Q2 in long-haul coupled-core multicore fibre transmission |
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| 1st Author's Name | Shohei Beppu |
| 1st Author's Affiliation | KDDI Research(KDDI Research) |
| 2nd Author's Name | Daiki Soma |
| 2nd Author's Affiliation | KDDI Research(KDDI Research) |
| 3rd Author's Name | Noboru Yoshikane |
| 3rd Author's Affiliation | KDDI Research(KDDI Research) |
| 4th Author's Name | Takehiro Tsuritani |
| 4th Author's Affiliation | KDDI Research(KDDI Research) |
| Date | 2023-01-13 |
| Paper # | OCS2022-65 |
| Volume (vol) | vol.122 |
| Number (no) | OCS-332 |
| Page | pp.pp.27-32(OCS), |
| #Pages | 6 |
| Date of Issue | 2023-01-05 (OCS) |