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We report some recent research activities of multicore EDFAs with cladding-pumped technology. We successfully developed cladding-pumped MC-EDFAs with C-band L-band application, respectively. Cladding-pumped L-band MC-EDFA realized output power of 19 dBm for each core between 1576–1603 nm with 33 % reduced power consumption.
Space-division multiplexing requires spatial-multiplexers that support over 10 modes with low insertion loss and low mode-dependent loss. Photonic lantern spatial multiplexers provide a lossless interface between N single-mode fibers and the N modes of a multi-mode fiber. Devices fabricated using all-fiber technology and 3D waveguide technology have enabled transmission in multi-mode fibers supporting...
High extinction ratio optical modulation using Mach-Zehnder interferometer with active Y-branch is proposed. The measured extinction ratio was over 60 dB, and we successfully operated optical two-tone signal generation over a long period of time with automatic bias control technique.
We report recent progress of high-performance Siwire-based WDM devices based on higher-order microring resonators and multi-stage delayed interferometers fabricated by 300-mm wafer-scale 193-nm ArF-immersion CMOS process.
We proposed a SDN-based networking framework for disaster recovery center in electric power communication networks. Typical tasks such as rapid data migration and fast disaster recovery have been proved efficient and reliable under this framework.
In this paper, we have experimentally analyzed the effect of hysteresis width on optical bistability present in single mode Fabry-Perot laser diode (SMFP-LD). Hysteresis width on optical bistability plays an important role on the latching operation. Input injected power and wavelength detuning are two parameters that can effect on the hysteresis width and hence the optical bistability. With this analysis...
To provide high-capacity/high-reliability optical-access and short-range links, a novel failure-recovery system utilizing protection optical switch units and multi-core fibers was developed. Configuring the proposed failure-recovery system, the developed multi-core fiber (MCF) connection technology (i.e., fan-in/-out modules and MCF connectors) and a protection optical-switch unit experimentally demonstrated...
The network architecture called Energy Efficient and Enhanced-type Data-centric Network (E3-DCN) is proposed for a new information centric network (ICN). E3-DCN not only realizes ICN but also has the ability of data generation by organizing and combining relevant resource such as original data and kinds of processing services. In addition, in order to improve energy efficiency of data transmission,...
Dynamic optical path network (DOPN) is a network based on hierarchical multi-granular fast circuit switching, mostly in optical domain. We discuss how this network technology is sustainable, eliminating energy and capacity crunch in the future network.
We solve an optimization problem for small cell power control considering the hourly network capacity demand of mobile access networks. The model is evaluated under urban, suburban and rural test cases to evaluate optimal transmit powers and corresponding power savings.
We proposed baseband AMO-OFDM transmission using PDM based I/Q separation in IM/DD system. In compare with up-conversion, we experimentally verified performance. As a result, optical spectral efficiency was better as 7.2bit/s/Hz. It has simpler hardware and reduces complexity compared to IF up-conversion or Hermitian symmetry in IM/DD based PDM-OFDM system.
MPLS Transport Profile (TP) uses a subset of the existing MPLS toolkit which represents the minimal amount of functionality that is needed in a transport network environment. MPLS-TP delivers the richness and reliability of operations, administration and maintenance (OAM) mechanisms that are characteristics of transport technology at the same time as it will support packet-based services more efficiently...
We propose a polarization beam splitter (PBS) based on a bridged silicon nanowaveguide directional coupler. The device is designed via 3D-FDTD simulation, and demonstrated experimentally. The measured polarization extinction ratio and the insertion loss of the PBS with 7.5-µm-long coupling length and 550 nm-wide bridged waveguides width are about 22 dB and 2 dB, respectively, for a TE-mode optical...
We analyze the performance of existing E-PON system that support a 64-way split and transmission distance of 50km using a reach extender. We experimentally demonstrated that it can provide a 950 Mbps and 860 Mbps throughputs at a down-/upstream direction.
Digital coherent superposition (DCS) provides an interesting approach to combat the fiber nonlinearity by trading off the spectrum efficiency. In this paper, we apply DCS of phase-conjugated OFDM subcarriers in two approaches. One is the DCS of OFDM subcarriers in the single polarization, denoted as SP-DCS-OFDM. The other is in the dual polarizations, or DP-DCS-OFDM. We show that both of them can...
We propose a downlink transmission timing shift in the fronthaul that advances the downlink transmission timing in order to improve the frame efficiency for time-division duplex radio access network in the centralized radio access network architecture. Numerical results show that the proposed technique provides high frame efficiency regardless of the optical transmission length in the fronthaul.
In this paper, we have demonstrated an inline conversion of transmission or reflection spectra of two fiber Bragg gratings (FBGs) having a different Bragg wavelength by incorporating a polarization-diversity loop without reconfiguring the filter structure. The proposed apparatus consists of a fiber-pigtailed polarization beam splitter, two FBGs, and three quarter-wave plates (QWPs). Without requiring...
We report the nanogap resonator with the straight waveguide without the ring shape resonator, which is replaced with a straight waveguide, metallic layer, and nanogap. We use the numerical method to investigate the resonant properties of the structure. The results reveal that the proposed structure has the band stop characteristic.
Generation of 40GHz optical pulses with ultra-low phase noise is demonstrated experimentally by a self-starting dual-loop OEO with balance detection. The pulses are achieved with the full-width-at-half-maximum of 7.23ps, extinction ratio of 19.8dB, optical signal to noise ratio of 45dB and timing-jitter of 25.4fs in the 100Hz to 10MHz range.
We propose a nonlinearity compensation scheme using a monitoring channel in radio over fiber (RoF) systems. Our simulation results show that the proposed scheme can almost remove the error vector magnitude (EVM) degradation induced by the nonlinear function of a laser.
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