Search results for: K Saitoh
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Journal of Fish Biology > 92 > 5 > 1342 - 1358
This study clarifies the location, size and age at the onset of metamorphosis in Japanese eels Anguilla japonica through oceanic surveys, rearing experiments and analyses of the morphology and otoliths of leptocephali and glass eels. Twenty‐eight metamorphosing leptocephali were collected in the mesoscale eddy region to the east of Taiwan during research expeditions in 2004. Rearing experiments showed...
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A low-loss and low-crosstalk Mach-Zehnder mode/wavelength multi/demultiplexer based on silica-PLC platform is proposed for WDM/MDM transmission. The Mach-Zehnder filter for “mode” and “wavelength” can be constructed by newly designed broadband 3dB-mode-divider. Furthermore, using Si/silica hybrid platform, footprint of the chip can be drastically reduced.
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We demonstrate the first 1-Pb/s unidirectional inline-amplified transmission over 205.6-km of single-mode 32-core fiber within C-band only. 96-Gbaud LDPC-coded PDM-16QAM channels with FEC redundancy of 12.75% realize high-aggregate spectral efficiency of 217.6 b/s/Hz.
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We demonstrate 32-core dense space-division multiplexed (DSDM) unidirectional transmission of PDM-16QAM 20-WDM signals over 1644.8 km employing a low-crosstalk single-mode heterogeneous 32-core fiber in a partial recirculating-loop system.
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A method is described for applying space-time coding implemented by Hadamard transform to SDM transmission. Experiments demonstrated that the method substantially improves mode dependent loss tolerance and enables transmission reach to be enhanced by 20%.
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We demonstrate 246 μm cladding 6-mode 19-core fiber and realize twice the spatial density of other multi-core fiber with more than 100 channels, while achieving the lowest loss and differential mode delay of 0.33 ns/km.
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High-density single-mode multicore fibers were designed and fabricated. A heterogeneous 30-core fiber realized a low crosstalk of −55 dB. A quasi-single-mode homogeneous 31-core fiber attained the highest core count as a single-mode multicore fiber.
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Multicore fibers and few-mode fibers have the potential to realize dense-space-division multiplexing systems. Several dense-space-division multiplexing system transmission experiments over multicore fibers and few-mode fibers have been demonstrated so far. Multicore fibers, including recent results by our group, are reviewed in this paper.
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Group delay spread of strongly-coupled 3-core fibres is investigated through the principal mode analysis. Calculated and measured results are in good agreement and group delay spread can be further reduced by adding an air-hole to the centre of the fibre.
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The inter-core crosstalk of a fabricated few-mode multicore fibre is theoretically and experimentally investigated. By changing the direction of the LP11 mode, the crosstalk between the LP11 mode and the LP01 mode decreased by more than 10 dB.
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A homogeneous 31-core fibre with a cladding diameter of 230 μm for quasi-single-mode transmission is designed and fabricated. LP01-crosstalk of −38.4 dB/11 km at 1550 nm is achieved by using few-mode trench-assisted cores.
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We experimentally evaluate the relationship between mode dependent loss (MDL) and Q penalty for few-mode fibre transmission. We employ a low-MDL recirculating loop and free-space-optics type MDL equaliser and transmit 3-mode signals with PDM-16QAM modulation.
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A 30-core fiber with heterogeneous cores that achieved large spatial multiplicity and low crosstalk of less than −40 dB at 100 km was demonstrated. The correlation lengths were estimated to be more than 1 m.
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A mode multiplexer/demultiplexer with a fused-fibre fan-in/fan-out device for three-mode operation of LP01, LP11a, and LP11b is demonstrated using a partially elongated multi-core fibre. A fabricated mode multiplexer/demultiplexer exhibited a coupling efficiency greater than 79% over the C band.
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Few-mode multicore fiber (FM-MCF) has the potential to improve the transmission capacity of a fiber drastically. Challenges in designing FM-MCF and characteristics of our fabricated FM-MCF for highly dense space-division multiplexing are reviewed.
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Fan-in/fan-out device for splicing to 12 core multi-core fiber is fabricated. Maximum loss of 4.7 dB at C-band and the worst crosstalk of −45 dB are confirmed in fan-in and fan-out with 20 m-long MCF.
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We demonstrate dense SDM transmission of 20-WDM multi-carrier PDM-32QAM signals over a 40-km 12-core × 3-mode fiber with 247.9-b/s/Hz spectral efficiency. Parallel MIMO equalization enables 21-ns DMD compensation with 61 TDE taps per subcarrier.
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A mode multiplexer/demultiplexer based on a partially elongated multi-core fiber is designed and fabricated. The mode conversion from the LP01 mode to the LP11 mode at two wavelengths is demonstrated by changing the elongating condition.
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