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Photonic Networks


FSTJ 1999-08 Cover Image

1999-07(Vol.35, No.1)



1999-7(Vol.35, No.1) Contents

1. Preface (49 KB)
---[Yukou Mochida , Member of the Board Fujitsu Laboratories Ltd. ]
2. Photonic Networks and their Forward View (229 KB)
This paper introduces a vision for photonic networks and presents their forward view in which this network will provide a vast increase in capacity and a flexible, expandable, and highly reliable transparent network for the 21st century. First, this paper describes the concept and development road maps of photonic networks. Then, it discusses wavelength division multiplexing technology, optical node technologies such as the optical add-drop multiplexer and optical cross-connect systems, and the new optical components and devices that will support photonic networks. ---[Hideo Kuwahara, Hajime Imai, Takashi Touge, Koichi Ohta ]
3. SONET/SDH Optical Transmission System (314 KB)
This paper describes Fujitsu's SONET/SDH transmission system. Fujitsu produces the Fujitsu Lightwave Add/Drop Shuttle (FLASH) series, which conform to the SONET/SDH standard. The FLASH series was well received in the North America market. Also, this paper describes Fujitsu's plans for future equipment and the key technologies used in some of Fujitsu's new optical transmission systems. ---[Kenji Sato, Masahiro Shinbashi, Atsuki Taniguchi, Takashi Wakabayashi]
4. WDM Optical Fiber Transmission Systems (231 KB)
This paper introduces Fujitsu's wavelength division multiplexing (WDM) systems and the technologies they incorporate. Two types of systems have been developed; one is for a long-haul network and other is for a metro network. These systems have a high-capacity (maximum 320 Gb/s) and good performance (transmission up to 600 km) and are very compact. They can easily be modified to meet customers' needs because a common platform is used for all configurations. ---[Daisuke Maruhashi, Kazuo Yamane, Hiroyasu Sumiya, Yasuo Nagai]
5. WDM Optical Submarine Network Systems (140 KB)
This paper describes optical submarine network systems that support 160 Gb/s capacity (10 Gb/s x 16λ) per fiber. These advanced systems enable practical and cost-effective deployment of networks with 4 fiber pair optical submarine cables, and total capacity of 640 Gb/s. A typical network configuration and the relevant equipment for such networks are outlined. The equipment includes submersible wide-band repeaters, optical ADM branching units and line terminal equipment, which we have developed making full use of our advanced optical technology. Our ultra-large capacity (10.7 Gb/s x 66zλ) transmission experiment, and enabling technologies for future Tera-bit transmission systems are also summarized. New network configurations using OADM or Internet Protocol (IP) routers are proposed for next generation WDM submarine networks. ---[Masuo Suyama, Masato Nagayama, Haruki Watanabe, Haruo Fujiwara, Colin Anderson ]
6. Photonic Networking Using Optical Add Drop Multiplexers and Optical Cross-Connects (337 KB)
The photonic network will enable the construction of high-capacity and flexible optical communication systems for the future data-centric era. Optical add drop multiplexers (OADMs) and optical cross connects (OXCs) along with already mature DWDM systems are key technologies for photonic networking. Prototype systems of OADMs based on the acousto-optic tunable filter (AOTF) and OXCs based on PLC optical switches have been demonstrated. This paper provides a perspective of the latest optical path layer technologies. ---[Terumi Chikama, Hiroshi Onaka, Satoshi Kuroyanagi ]
7. Global Optical Access Systems Based on ATM-PON (619 KB)
This paper discusses a global optical access network architecture to consolidate an economical ATM-PON (Asynchronous Transfer Mode-Passive Optical Network) that is compliant with the international standard, a flexible access node configuration with a growable IP functionality and legacy service support, and a regional transfer network. The GFR service support functionality and dynamic ATM-PON bandwidth allocation to cope with IP traffic growth are discussed. Also, since cost-effectiveness is the key factor in the access network, we also present an optical device and assembling technology. The main parts of this architecture and technology have been successfully hardware-implemented. ---[Mitsuhiro Yano, Kazuo Yamaguchi, Haruo Yamashita ]
8. Photonic Network Management (250 KB)
The deployment of point-to-point WDM systems has just begun in core networks to accommodate the explosive growth in bandwidth demands of Internet traffic and data communications. Now that the basic technologies for wavelength division multiplexing and optical amplifiers have been established, wavelength path management is the key to full exploitation of the advantages of meshed photonic networks by improving the reliability and efficiency of networks. After describing the photonic network layer model, this paper describes photonic network management architecture and a flexible optical path management. Then, a new distributed restoration technique and a spare capacity design method are proposed. The applicability of the proposed technique is discussed based on the results of prototyping of an optical crossconnect management system. ---[Keiji Miyazaki, Yasuki Fujii, Takafumi Chujo ]
9. Wideband WDM Erbium-doped Optical Fiber Amplifiers for 10 Gb/s, 32-channel SMF Transmission Systems (157 KB)
We have developed novel wide-dynamic-range WDM optical fiber amplifiers for 10 Gb/s, 32-channel SMF transmission systems. These amplifiers consist of a low-noise pre-amplifier section, a mid-attenuator for loss compensation of a dispersion compensator and ALC operation, and a post-amplifier section for a high output power. These WDM amplifiers are also designed to allow in-service channel upgrades and in-service accommodation of external pump units. We have confirmed the superior performance of these WDM amplifiers by performing 320 Gb/s (10 Gb/s x 32-channel) transmissions over 320 km (80 km x 4 span) of SMF, achieving a bit error rate of less than 10-15 for all channels. ---[Susumu Kinoshita, Tadashi Okiyama, Kaoru Moriya ]
10. High-Speed Optical Transmission Systems (170 KB)
To meet the severe capacity demands in current fiber communication networks, an advanced integration of the high-speed time-division multiplexing (TDM) and multi-channel wavelength-division multiplexing (WDM) data transmission schemes is indispensable. This paper describes our R&D activities into high-speed TDM systems of photonic networks. In high-speed TDM systems, fiber dispersion and non-linearity place limits on transmission speed and distance, and management of these fiber effects is the key for higher bit-rate systems. Even in 10 Gb/s systems, to achieve a satisfactory transmission distance, we had to cope with the speed limit of fiber. At the same time, we have reduced the size and cost of transmitters and receivers so they can be used as "network comodities" in small and simple network equipment. In 40 Gb/s systems, we have conducted experiments with several automatic compensation techniques for overcoming the crucial transmission speed limit of optical fibers. ---[Hiroshi Hamano, George Ishikawa, Katsuya Yamashita ]
11. Semiconductor Optical Active Devices for Photonic Networks (95 KB)
This paper describes recent progress in semiconductor optical active devices for photonic networks. The characteristics of modulator-integrated distributed feedback lasers, tapered-thickness waveguide lasers, and semiconductor optical amplifiers are improved by introducing a strained-layer into the active regions. Experimental results show that these devices are promising for photonic networks. ---[Kiyohide Wakao, Haruhisa Soda, Yuji Kotaki ]
12. Ti:LiNbO₃ Acousto-Optic Tunable Filter (AOTF) (158 KB)
We have developed the following new elements for an AOTF: an intersecting waveguide PBS which has a high extinction ratio, low loss, and wavelength independent characteristics; a film-loaded SAW guide (SAWG) which has a strong confinement, excellent filter characteristics, and provides a high design flexibility; and a 0-gap directional coupler type reflector which enables high-performance waveguide integration. These elements were combined to construct an AOTF consisting of five film-loaded SAWGs. The through and drop lights in this AOTF are filtered by three stages of the new SAWG. The 3 dB bandwidth and extinction ratio are 0.37 nm and less than -27 dB, respectively. An optical ADM system that incorporated the new AOTF has demonstrated 10 Gb/s x 32-channel transmission with a 0.8 nm wavelength spacing. ---[Tadao Nakazawa, Shinji Taniguchi, Minoru Seino ]
13. Virtually Imaged Phased Array (271 KB)
A Virtually Imaged Phased Array (VIPA) is a simple design of an optical element which shows large angular-dispersion versus wavelength change. It consists of a semi-cylindrical lens and a thin plate of glass on which reflection coatings are formed. Both theory and experiment show that the angular dispersion is 0.5 degree/nm, which is large enough to demultiplex dense WDM channels. When the VIPA is used in a wavelength demultiplexer, the fiber coupling efficiency, which determines the insertion loss and the crosstalk, is important. The characteristics of the demultiplexer using the VIPA are analyzed. Temperature dependence of the demultiplexing performance is also an important issue. A temperature insensitive design of the VIPA is described. Another application of the VIPA is chromatic dispersion compensation in a fiber transmission line. The scheme for chromatic dispersion device using the VIPA is discussed. ---[Masataka Shirasaki ]
14. Wavelength Conversion Technologies for Photonic Network Systems (184 KB)
This paper reviews wavelength conversion technologies for photonic network systems. A simple method of four-wave mixing (FWM) wavelength conversion using a λ/4-shifted DFB laser and one using a polarization-maintaining highly-nonlinear dispersion-shifted fiber (PM-HNL-DSF) are presented. For both wavelength conversions, transmission experiments with dispersion compensation were performed using phase conjugation. A 10 Gb/s transmission over 100 km was done using the λ/4 shifted DFB laser wave-length converter, and a transmission over 100 km for 32 WDM (wavelength division multiplexed) signals of 10 Gb/s each was performed using the PM-HNL-DSF wavelength converter. Then, this paper discusses possible applications of these technologies to the photonic network systems. --[Hiroshi Ishikawa, Shigeki Watanabe, Haruhiko Kuwatsuka ]

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