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Front-line Researchers
 Makio Kashino, Senior Distinguished Researcher, NTT Communication Science Laboratories
Toward Life-enriching Technologies
Overview
Makio Kashino, an NTT Senior Distinguished Researcher, has enjoyed Japanese and Chinese classical literature since childhood. He has been particularly influenced by the Zhuangzi (classical Taoist book) by the Chinese author of the same name and the Hojoki (An Account of My Hut) by the Japanese author and poet Kamo no Chomei. Both of these philosophize about the impermanence of worldly things. We asked Dr. Kashino, a unique researcher who attempts to explain hearing and communication from the viewpoints of psychology, neuroscience, and information science, to tell us about the manner, significance, and future of his type of research.
Feature Articles: System LSI Design for Broadband Optical Access Network Systems
 System LSI Design Technology for Communications Networks
Abstract
The first set of Feature Articles in this issue describes research and development of system large-scale integration (LSI) technology (also known as system-on-a-chip (SoC) technology) and high-speed front-end electronics for optical access systems being conducted at NTT Microsystem Integration Laboratories. This article provides an overview and the other articles discuss their roles and characteristics well as related design technology and issues.
- Cooperative Hardware/software Design Technology
Abstract
In this article, we introduce a hardware/software co-design simulation method for testing the cooperative design of hardware and software for system-on-a-chip (SoC) devices. For SoCs, which incorporate dedicated processing circuits and a processor, combined testing of the software running on the processor and the operations of the dedicated circuits must be done from the initial design stages in order to reduce the amount of redesign and the turnaround time, i.e., the number of person-hours of work required. Our cooperative simulation method uses virtual hardware. We discuss its effectiveness by referring to real examples.
- MAC LSI Design Technology for Optical Access Communications
Abstract
In this article, we explain the development process and architecture of a media access control (MAC) large-scale integrated circuit (LSI). The MAC LSI is a very important component that provides most of the functions of an optical line terminal and optical network unit, which are the main devices in an optical access system. The required functions include the passive optical network (PON) interface, buffers, bridges, and maintenance & authentication.
- Design Verification Using Field-programmable Gate Arrays for Optical Access Communications SoC
Abstract
We describe evaluation technology that uses field-programmable gate arrays (FPGAs) to test a system on a chip (SoC). This should reduce the time taken for testing SoCs used in optical access communications by letting us conduct tests using FPGAs in parallel with conventional testing to reduce the testing time and improve the design quality.
- 10-Gbit/s Burst-mode Receiver Integrated Circuits for Broadband Optical Access Networks
Abstract
We introduce burst-mode receiver integrated circuits that can respond instantaneously to a suddenly arriving optical signal and receive it correctly. They are suitable for the next-generation optical access system (10G-EPON: 10-Gbit/s Ethernet passive optical network), which requires a receiver that can receive high-speed (10-Gbit/s) optical burst signals, unlike typical receivers which receive continuous signals.
Feature Articles: R&D of Optical Component Technologies for 100-Gbit/s Digital Coherent Communications
- Optical Device Technologies for Future Network Evolution
Abstract
This article outlines progress in optical device technologies for photonic networks, focusing on integrated optical device technologies for digital coherent optical transmission technologies. With the rapid spread of fiber to the home (FTTH), broadband video services and mobile Internet devices now require a highly functional optical network infrastructure with a large capacity.
- Wavelength-tunable Lasers for Next-generation Optical Networks
Abstract
Wavelength-tunable lasers are key components as light sources in large-capacity optical core networks that use dense wavelength-division-multiplexing techniques. In next-generation optical networks, an advanced modulation/detection technique will be used, and low phase-noise characteristics will be essential for tunable laser sources. This article reviews techniques for reducing the phase noise of tunable lasers and describes a narrow-linewidth tunable distributed feedback laser array that we have developed.
- Multilevel Optical Modulator Utilizing PLC-LiNbO3 Hybrid-integration Technology
Abstract
Multilevel optical modulators are key devices for optical transmission systems with transmission rates of 100 Gbit/s and beyond. For such modulators, NTT Photonics Laboratories has developed hybrid-integration technology for silica planar lightwave circuits (PLCs) and LiNbO3 phase modulator arrays. This makes possible various kinds of multilevel modulator featuring a compact size, low loss, and high scalability. We review our recent progress in PLC-LiNbO3 technology and describe some integrated multilevel modulators: 100-Gbit/s PDM-QPSK and post-100G OFDM-QPSK and 64QAM modulators (PDM: polarization-division multiplexing, QPSK: quadrature phase-shift keying, 100G: 100-Gbit/s, OFDM: orthogonal frequency-division multiplexing, QAM: quadrature amplitude modulation).
- 100-Gbit/s Optical Receiver Front-end Module Technology
Abstract
We have been developing a 100-Gbit/s-class optical receiver front-end module with a hybrid integration structure using silica-based planar lightwave circuit technology to perform demultiplexing and demodulation in digital coherent photonic network systems. In this article, we describe the module structure and the integration technology that we have developed at NTT Photonics Laboratories.
- Photodiodes and Transimpedance Amplifiers for 100-Gbit/s Digital Coherent Optical Communications
Abstract
To increase transmission capacity and extend transmission distance, 100-Gbit/s digital coherent optical communications systems have been researched. NTT Photonics Laboratories has developed photodiodes that exhibit a good high-frequency response even under high optical input power and transimpedance amplifiers that have both broadband characteristics and a wide input dynamic range.
Regular Articles
- Antenna Model and Its Application to System Design in the Millimeter-wave Wireless Personal Area Networks Standard
Abstract
This article describes an antenna model developed for the system design and standardization of millimeter-wave wireless personal area networks (WPANs). It also discusses why a new antenna model is required for standardization activities. The developed antenna model is a simple mathematical analog. It provides a main-lobe pattern and averaged side-lobe level by setting the antenna”Ēs half-power beamwidth. This model was adopted as a reference antenna model in the channel model document of the IEEE 802.15.3c millimeter-wave WPAN task group.
- Compressed Sensing Technology for Flexible Wireless System
Abstract
We are developing a flexible wireless system (FWS) in response to the rapid development of and changes to wireless radio environments. FWS is a unified wireless platform that simultaneously receives various types of wireless signals at distributed remote stations and performs signal processing at the central station by transferring the received radio wave data via the wired access line. As a partial fulfillment of our system, we have applied compressed sensing technology as a radio wave data compression technology for FWS. Compressed sensing is a new framework for solving an ill-posed inverse problem of a sparse signal. Direct translation of compressed sensing in the sense of wireless technology is as follows: radio wave data can be received, transmitted, and reconstructed using sub-Nyquist rate information without aliasing if the original radio wave is sparse. To provide a full understanding of our approach, this article first reviews basic knowledge about compressed sensing and then describes the application scenario of compressed sensing in FWS.
Global Standardization Activities
Papers Published in Technical Journals and Conference Proceedings
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