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The fast extraction kicker magnets of the 50 GeV synchrotron are now in an intensive R&D stage. In the 50 GeV ring, the fast extraction system is designed to deliver the 50 GeV beam to the downstream neutrino oscillation experiment beam line with the Super-Kamiokande detector. At the same time, the fast extraction line is required to function as a beam abort, in case of hardware failure during acceleration of the beam from 3 GeV to 50 GeV. In order to fulfill both demands, the extraction system is designed to accommodate bipolar beam extraction. A new technology to make the bipolar kicker magnet system, using a Symmetric Blumlein Pulse Forming Network (SBPFN) system, has been introduced. Its validity is being investigated, both theoretically and experimentally. R&D programs aimed at establishing some of the important technical elements in the fast extraction kicker system are presently in progress. This R&D includes experimental studies of the bipolar kicker principle and the development of IGBT switching modules that satisfy full switching capability of the designed current and voltage. [ABSTRACT FROM AUTHOR]

This paper describes recent technical challenges and the progress toward the realization of the optical transport network (OTN) based on 43 Gb/s channel. We describe the new digital frame format "OTU3: Optical Channel Transport Unit 3," which is standardized in ITU-T for OTN, for the enhancement of the network management capability in the OTN based on 43-Gb/s channels. We first proposed 43-Gb/s/ch dense wavelength-division multiplexing (DWDM) dispersion-managed transmission system using carrier-suppressed return-to-zero (CS-RZ) format that has several attractive features; it advances the evolution of OTN into 100 GHz-spaced long-haul DWDM transport networks. The first wavelength-division multiplexing (WDM) field trials confirmed the superiority of CS-RZ format in the DWDM transmission performance for the first time. The first 1 Tb/s (25 × 43 Gb/s) WDM field trial confirmed the excellent network management capability of OTU3 in future data-centric OTN using the newly developed 43-Gb/s OTN line-terminal prototype. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel duobinary-mode-splitting scheme that uses wideband phase-shift-keying (PSK)/amplitude-shift-keying (ASK) conversion for modulation and detection of bandwidth-reduced return-to-zero (RZ) modulation formats. We have first demonstrated that the proposed scheme greatly simplifies the modulation process of the duobinary carrier-suppressed RZ format (DCS-RZ) based on baseband binary nonreturn-to-zero (NRZ) modulation. We also proposed carrier-suppressed RZ differential-phase-shift-keying format (CS-RZ DPSK) as a novel bandwidth-reduced RZ format by applying the proposed scheme in the detection process. These novel RZ formats are shown to be very useful for dense wavelength-division multiplexed (DWDM) transport systems using high-speed channels, over 40 Gb/s, with spectrum efficiencies higher than 0.4 b/s/Hz. We demonstrate that the proposed modulation and detection scheme greatly simplifies the DWDM transmitter and receiver configuration if the periodicity of the optical PSK/ASK conversion filter equals the WDM channel spacing. The large tolerance of the formats against several fiber nonlinearities and their wide dispersion tolerance characteristics are tested at the channel rate of 43 Gb/s with 100-GHz spacing. The novel CS-RZ DPSK format offers higher nonlinearity tolerance against cross-phase modulation than does the DCS-RZ format. [ABSTRACT FROM PUBLISHER]

The optical transport network (OTN) based on 43-Gb/s channels is expected to be the carriers' next-generation core network. This paper discusses its system architecture, from the requirements of services, protection, and management, and shows a feasible scenario to ensure the rapid penetration of the 43-Gb/s-based OTN. It also describes the design concept and functions of the first 43-Gb/s OTN line terminal. The line terminal deploys time-division multiplexing to handle client signals and provides high-quality, multiple transparent services, such as synchronous optical network/synchronous digital hierarchy and gigabit Ethernet. The configuration and features of the actual fabricated system are described. [ABSTRACT FROM PUBLISHER]

Sophistication of the transmission format for 40-Gb/s/ch WDM networks is indispensable. In long-haul transmission applications, the selection of transmission format should be a principal issue. Recently, we have proposed several transmission formats including carrier-suppressed return-to-zero (CS-RZ) and duo-binary-carrier-suppressed (DCS-RZ), in so doing addressing the issue of superior performance versus fiber nonlinearity and spectral efficiency. The special spectrum structure of these formats enables a novel mode-splitting detection scheme. The scheme realizes a variety of applications in 40-Gb/s/ch transmission; including expansion of dispersion tolerance, automatic dispersion compensation, and BER improvement. We achieved 1.6 times. expansion of dispersion tolerance of 43-Gb/s DCS-RZ signals by introducing mode-splitting in the receiver. By applying the mode-splitting scheme for CS-RZ signals, we also demonstrated precise chromatic dispersion measurement with its sign detection without the need for any dithering operation and its application to automatic dispersion compensation at 43-Gb/s CS-RZ transmission. [ABSTRACT FROM PUBLISHER]

Discusses the features of the opposite-field type superconducting septum magnet used for particle beam injection and extraction of particle accelerators. Principles of the opposite-field septum magnet system; Force-free structure; Cancellation of the leakage flux; Current density of the septum.