Hideaki Tsushima

Photonic network R&D activities in Japan-current activities and future perspectives

R&D activities on photonic networks in Japan are presented. First, milestones in current ongoing R&D programs supported by Japanese government agencies are introduced, including long-distance and wavelength division multiplexing (WDM) fiber transmission, wavelength routing, optical burst switching (OBS), and control-plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP-over-WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R&D programs for photonic networks over the next 5 years until 2010, by focusing on the report that has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R&D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis, through the customers initiative to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

1.244-Gb/s 32-channel transmission using a shelf-mounted continuous-phase FSK optical heterodyne system

A total capacity of 40 Gb/s is achieved using a shelf-mounted continuous-phase frequency-shift-keying (CPFSK) optical heterodyne frequency-division-multiplexing (FDM) transmission system with 32 optical channels and a bit-rate of 1.244-Gb/s per channel. For achieving a stable bit-error-rate (BER) characteristics with high-sensitivity, narrow-linewidth laser diodes, a channel-spacing stabilization circuit, and an optical tuner are developed. The obtained sensitivity at a BER of 10/sup -9/ for fiber transmission over 121 km ranges from -45.1 to -44.2 dBm, which is 9.8-10.7 dB lower than the shot-noise-limited sensitivity. The crosstalk penalty is suppressed to within 0.1 dB. The developed system has feasibility achieving a distribution system which can distribute more than 250 HDTV (high definition television) signals or 1250 current-standard TV signals to about 8000 subscribers 10 km from the office, or a 40-Gb/s trunk-line system with a fiber span of more than 50 km. >

OTN-based optical cross-connect systems to create reliable and transparent optical networks

The Optical Transport Network (OTN) is the extremely important technology to create the next-generation core optical networks with the capacity of several Tbit/s, because it can contribute to the reliability and transparency. We discuss the OTN-based Optical Cross-Connect systems (OXCs), and verify the fast restoration using OTN functionality.

Alternate-mark-inversion optical continuous phase FSK heterodyne transmission using delay-line demodulation

Alternate-mark-inversion (AMI) optical continuous phase (CP) frequency-shift keying (FSK) heterodyne transmission using delay-line demodulation which has a higher receiver sensitivity compared to the transmission using single-filter demodulation has been achieved. Since the proposed delay-line demodulation method directly converts the received AMI-CPFSK signal into the nonreturn to zero (NRZ) baseband signal without the use of an AMI decoder, a heterodyne receiver with the same configuration as the conventional CPFSK transmission system is realized, even though AMI line coding is applied to the system. Transmission experiments at 622 Mb/s have been demonstrated for both pseudorandom 2/sup 7/-1 and 2/sup 23/-1-b patterns at the same receiver sensitivity of -41.1 dBm (the PD input power). >

Optical cross-connect systems for restoration of backbone fiber networks

Summary form only given. As the capacity of backbone networks is becoming larger, restoration against fiber/cable failures must become faster, because large amounts of data would be lost during the failure. The optical cross-connect (OXC) technology is an attractive alternative for fast restoration, and has the potential to provide bandwidth-management capability in future wavelength-division multiplexing (WDM) networks. This paper describes newly developed OXC systems with a low insertion loss of 1.16 dB and a high-speed restoration of <150 ms.

High-speed optical protection system using MEMS optical switch triggered by SONET performance monitor

High-speed and low cost optical 1+1 protection system using a MEMS optical switch triggered by SONET performance monitor (SD/SF) for high accuracy protection was developed. 980 /spl mu/s switching time of optical power recovery was demonstrated.

Properties of polarization noise caused by external disturbances in single-mode fiber transmission systems

The properties of polarization noise caused by external disturbances in intensity modulation/direct detection transmission systems that have polarization-dependent optical devices are analyzed. It is experimentally shown that the noise consists of additive noise and multiplicative noise. The multiplicative noise directly disturbs signals, even if the external disturbance is of a low frequency. The signal to polarization noise ratio easily reaches the ratio at which flickers obstruct the picture in an analog TV transmission system. The polarization noise caused by external disturbances is also discussed. It is shown that disturbances to the fiber can make the maximum noise n/sup 2/ times greater than the noise caused by a single disturbance, where n is the number of disturbances. >

Photonic network R and D activities in Japan

R and D activities on photonic networks in Japan are presented. First, milestones in current, ongoing R and D programs supported by Japanese government agencies are introduced, including long-distance and WDM fiber transmission, wavelength routing, optical burst switching, and control plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP over WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R and D programs for photonic networks over the next five years until 2010, by focusing on the report which has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R and D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis through the customers initiative, to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.