Ryo Takahashi

High-speed sample and hold using low temperature grown GaAs MSM switches for photonic A/D conversion

Summary form only given. With the evergrowing demand for bandwidth, the need for high-speed A/D converters operating at GSa/s sampling rates has emerged in the areas of radar and microwave communications. As a solution, the idea of combining the low jitter and high speed advantages of photonics with electrical A/D converters has spawned a number of photonic A/D conversion systems. In our system, we utilize a sample and hold scheme with LT grown GaAs MSM switches. The short recombination lifetime and high mobility of LT GaAs allow high-speed operation with good sensitivity. Optically triggered by a short-pulse laser, the switches would be attached to a transmission line and would sample the input electrical signal onto a hold capacitor.

Torus-Topology Data Center Networks with Hybrid Optoelectronic Routers

Ever-growing data centers are currently the main providers for a wide diversity of services that involve handling unprecedented volumes of data traffic. However, it is getting increasingly difficult to cope with the growing demand while keeping other requirements under control such as low cost, high-energy efficiency, and low latency. Photonic networks are expected to be the savior that can take data centers to a new paradigm by providing solutions to the above challenges and thus enable their sustainable growth up to the far-off future.

Hybrid Optoelectronic Router for Future Optical Packet‐ Switched Networks

With the growing demand for bandwidth and the need to support new services, several challenges are awaiting future photonic networks. In particular, the performance of cur‐ rent network nodes dominated by electrical routers/switches is seen as a bottleneck that is accentuated by the pressing demand for reducing the network power consumption. With the concept of performing more node functions with optics/optoelectronics, opti‐ cal packet switching (OPS) provides a promising solution. We have developed a hybrid optoelectronic router (HOPR) prototype that exhibits low power consumption and low latency together with high functionality. The router is enabled by key optical/optoelec‐ tronic devices and subsystem technologies that are combined with CMOS electronics in a novel architecture to leverage the strengths of both optics/optoelectronics and electron‐ ics. In this chapter, we review our recent HOPR prototype developed for realizing a new photonic intra data center (DC) network. After briefly explaining about the HOPR‐based DC network, we highlight the underlying technologies of the new prototype that enables label processing, switching, and buffering of asynchronous arbitrary‐length 100‐Gbps (25‐Gbps × 4λs) burst‐mode optical packets with enhanced power efficiency and reduced latency.

100-Gb/s Optical Packet Switching Technologies for Data Center Networks

The hybrid optoelectronic router (HOPR) can efficiently allow the realizing of a highly-scalable and energy-efficient DC network. We present the recent developments on the 100-Gb/s underlying technologies that enable HOPR’s necessary functions.

Integrable ultralow-power nanophotonic devices on InP photonic crystals

Photonic crystal nanocavities are expected to greatly reduce the size and energy consumption of various optical devices. We have demonstrated this feature in all-optical switches and random access memories for on-chip nanophotonic integration.