Tsunetoshi Saito

Super-Nyquist-WDM transmission over 7,326-km seven-core fiber with capacity-distance product of 1.03 Exabit/s · km.

We show super-Nyquist-WDM transmission technique, where optical signals with duobinary-pulse shaping can be wavelength-multiplexed with frequency spacing of below baudrate. Duobinary-pulse shaping can reduce the signal bandwidth to be a half of baudrate while controlling inter-symbol interference can be compensated by the maximum likelihood sequence estimation in a receiver. First, we experimentally evaluate crosstalk characteristics as a function of channel spacing between the dual-channel DP-QPSK signals with duobinary-pulse shaping. As a result, the crosstalk penalty can be almost negligible as far as the ratio of baudrate to frequency spacing is maintained to be less than 1.20. Next, we demonstrate 140.7-Tbit/s, 7,326-km transmission of 7 × 201-channel 25-GHz-spaced super-Nyquist-WDM 100-Gbit/s optical signals using seven-core fiber and full C-band seven-core EDFAs. To the best of our knowledge, this is one of the first reports of high-capacity transmission experiments with capacity-distance product in excess of 1 Exabit/s · km.

110.9-Tbit/s SDM transmission over 6,370 km using a full C-band seven-core EDFA

We confirm the feasibility of 100-Tbit/s-class trans-oceanic SDM transmission. Using seven-core fiber spans with seven-core full C-band EDFAs, 7 × 264-channel quasi-Nyquist-WDM 60-Gbit/s PDM-QPSK signals are transmitted over 6,370 km.

Development of fiber bundle type fan-out for multicore fiber

We developed a compact fiber bundle type fan-out for multicore fiber by using capillary action of adhesive. The fan-out demonstrated low splice loss less than 0.35dB and low cross-talk less than -64dB in all cores.

100 GHz-32 ch athermal AWG with extremely low temperature dependency of center wavelength

New athermal AWG with 100 GHz-32 ch has been developed. This novel athermal AWG exhibits excellent property in temperature dependency of center wavelength less than /spl plusmn/0.01 nm under the temperature range 0 to 70/spl deg/C.

51.1-Tbit/s MCF transmission over 2,520 km using cladding pumped 7-core EDFAs

We demonstrate 51.1-Tb/s multi-core fiber transmission using cladding pumped 7-core EDFAs and confirmed a reachable distance of 2,520 km with 73 × 100-Gbit/s Nyquist-pulse-shaped DP-QPSK signals per core.

51.1-Tbit/s MCF Transmission Over 2520 km Using Cladding-Pumped Seven-Core EDFAs

Multicore erbium-doped fiber amplifiers (MC-EDFAs) are essential components to achieve long-haul multicore fiber (MCF) transmission. An attractive technique for reducing the number of components and power consumption is the cladding-pumping scheme in MC-EDFAs in which all cores are simultaneously pumped using a single high-power multimode laser diode. In this paper, we experimentally demonstrate long-haul MCF transmission using cladding-pumped seven-core EDFAs. We confirm that 73 × 128-Gbit/s Nyquist-pulse-shaped dual-polarization quadrature phase-shift keying signals are successfully transmitted over 2520-km seven-core fiber.

Development of MPO type 8-multicore fiber connector

We developed MPO type 8-MCF (56-core) connector. Rotational alignment with alignment member and absorption of protrusion difference using compressive strain were adopted. Fabricated 8-MCF connector demonstrated all core PC and connection loss <; 0.7 dB.

Cladding-Pumped L-Band Multicore EDFA with Reduced Power Consumption

Seven-core MC-EDFA pumped with single MM-LD optimized for L-band is developed. Output power of 19 dBm for each core is realized between 1576-1603nm with 33% reduced power consumption.

Development of small MT type 2-multicore fiber connector

We developed small MT type 2-MCF connector. PC condition for MT type MCF connector was studied theoretically and experimentally. Fabricated 2-MCF connector demonstrated return loss more than 46dB and connection loss less than 1.16dB.

Confirmation of Core Pitch Accuracy of Fiber Bundle Type Fan-Out for MCF

Core pitch measurement with σ≤0.147μm was achieved by developed precise measurement method for fiber bundle type fan-out (FBF). Accuracy of core pitch better than ±0.4μm was also confirmed for 7 and 19-core FBFs for MCFs.