Goji Nakagawa

A compact and lossless 8 × 8 SOA gate switch subsystem for WDM optical packet interconnections

We developed a compact 8 times 8 gate switch subsystem, which was integrated with eight 8:1 SOA modules (72-SOAs). We achieved a high-speed switching, lossless and colored operation.

WDM Optical Packet Interconnection using Multi-Gate SOA Switch Architecture for Peta-Flops Ultra-High-Performance Computing Systems

We propose a 100-Tbps-class throughput WDM optical packet interconnection for peta-flops ultra-high-performance computing systems using multi-gate SOA broadcast- and-elect switch architecture. The fundamental result of 6.4Tbps throughput (100Gbps x 64port) WDM optical packet interconnection is obtained.

High-speed and High-reliability Optical Selector for 256×256 Large-scale, Nanosecond-order Optical Switching

We have developed a high-performance 8-input and 1-output optical selector for 256×256-ports optical switching systems. This optical selector provides compactness and high reliability as well as high-speed switching of a few nanoseconds.

Lens-coupled laser diode module integrated on silicon platform

Recent interests in the development of multiservice systems have increased the activities be reduced. However, current commercial-grade manufacturing cannot satisfy these needs. The conventional assembly method results in the labor-intensive in optical access networks, such as fiber to the home (FTTH). For these systems to be viable, the optical module assemble costs and package size must process of finding the optimum optical coupling position. In addition, the number and size of parts cannot be reduced due to the difficulty of manipulating them. As a new approach for a lower cost, compact packaging solution, silicon platform technology is very promising. This paper describe a lens-coupled laser diode module integrated on a silicon platform, where a laser-diode, a GRIN rod lens, and single-mode fiber are hybridly integrated on a silicon platform by passive alignment.

Novel Optical Coupling Technique for Enhancing the Performance of Integrated 8-Input/1-Output SOA Gate-Switch Module

We developed 8-input/1-output (8:1) optical gate- switch module that is compact and reliable by proposing and developing a novel lens coupling scheme suitable for an 8:1 integrated SOA device for a multigate semiconductor optical amplifier (MG-SOA) switch system. We first designed special lenses that collect the tilted SOA beams and simultaneously magnify the pitch and beam size, and we fabricated a highly reliable optical module with hermetic sealing and laser-welded joints. The module exhibits low-loss coupling (~ 3.1 dB), high channel crosstalk (~ - 50 dB), high extinction ratio (>81 dB), and high-speed switching (~ 2.5 ns), confirming that this module is applicable to MG-SOA switching systems.

Compact photonic gateway for dynamic path control using acousto-optic tunable filter

A compact photonic gateway for wavelength-path control with a simple configuration at low cost was developed. The gateway achieves wavelength-path control by using acousto-optic tunable filters (AOTF). The fabricated four-channel integrated AOTF device exhibits a high performance with regard to polarization-independent characteristics, side-lobe suppression, higher extinction ratio, and narrower bandwidth for 100 GHz spacing. An AOTF subsystem was fabricated by combining an AOTF with the control circuit to exploit the AOTFs high-speed switching to the full and operate it stably for practical use and achieve stable operation of the AOTF. We manufactured the photonic gateway node by assembling the AOTF subsystem with the provisioning control and redundant system.

Evaluation of FSK light labels superimposed on 112 Gbps DP-QPSK signal with real-time coherent receiver and optical filter based decoder for light path tracing

We experimentally evaluate the feasibility of FSK light labels superimposed on 112 Gbps DP-QPSK signals using real time digital coherent receiver and optical filter based light label decoder.

High-speed SOA Gate switch driver with equal-length wiring and peaking techniques

We developed a high-speed SOA gate-switch driver using an equal-length wiring technique. It can drive two SOAs simultaneously at 300 mA with a rising time of 2.5 ns for high-speed and high-port count optical switches.

Crosstalk Analysis of FSK Light Label on 112 Gbps DP-QPSK Signal in CNCG ROADM Network

We investigated crosstalk of FSK supervisory channel superimposed on a 112 Gbps DP-QPSK caused by pass-band narrowing effect in CNCG ROADM network. We estimated maximum number of ROADM nodes and frequency misalignment tolerance between main signal and center frequency of WSS pass-band that the FSK light label technique could support.

Demonstration of integrated optical path monitoring sub-system in CDCG-ROADM network

We developed an integrated optical path monitoring sub-system prototype that fully integrates three functions; FSK light label monitor, in-band OSNR monitor, as well as conventional optical channel monitor, and successfully demonstrated the monitor operations for 112 Gbps DP-QPSK signals.