Kazuo Hagimoto

13.5-Tb/s (135 × 111-Gb/s/ch) no-guard-interval coherent OFDM transmission over 6,248 km using SNR maximized second-order DRA in the extended L-band

By employing 111Gb/s no-guard-interval coherent OFDM and SNR maximized second-order distributed Raman amplification in the extended L-band, we demonstrate the record capacity-distance product of 84.3Petabit/s.km (13.5Tb/s × 6,248km), and also 1Tb/s transmission over 9,612km.

13.4-Tb/s (134 × 111-Gb/s/ch) no-guard-interval coherent OFDM transmission over 3,600 km of SMF with 19-ps average PMD

We demonstrate the record capacity-distance product of 48.2 Petabit/s.km by using 111-Gb/s no-guard-interval coherent OFDM with 2-b/s/Hz spectral efficiency.

Optical repeater circuit design based on InAlAs/InGaAs HEMT digital IC technology

This paper describes an optical repeater circuit that uses an InAlAs/InGaAs HEMT digital integrated circuit (IC) chip set. The chip set includes a 64-Gb/s 2:1 multiplexer (MUX), a 40-Gb/s demultiplexer (DEMUX), a 46-Gb/s decision circuit (DEC), and a 48-GHz frequency divider (DIV). Electrically multiplexed and demultiplexed 40-Gb/s 300-km transmission is successfully demonstrated.

Limitations and challenges of single-carrier full 40-Gbit/s repeater system based on optical equalization and new circuit design

A single-carrier 10-Gbit/s system was installed into commercial networks and wavelength-division multiplexing technology was employed in laboratory tests to accelerate the transmission capacity to speeds of up to 1 Tera-bit/s. This successful transmission capability is based on high-speed circuit technology. This paper describes the problems and solutions for a single-carrier system with speeds of 40 Gbit/s or more. There are two major problems in implementing this system: one is how fast can electrical and photonic circuits operate and the other is how to accommodate certain kinds of dispersion limitations in long-haul transmission.

10-Gb/s strained MQW DFB-LD transmitter module and superlattice APD receiver module using GaAs MESFET IC's

This paper describes the design and performance of a 10-Gb/s laser diode (LD) transmitter and avalanche photodiode (APD) receiver, both of which are based on GaAs MESFET ICs. The LD transmitter consists of a strained MQW distributed-feedback LD and one chip LD driver IC. The module output power is +4.6 dBm at 10 Gb/s. The APD receiver consists of an InGaAsP/InAl/As superlattice-APD and an IC-preamplifier with the 10-Gb/s receiver sensitivity of /spl minus/27.4 dBm. As for the LD transmitter, we discuss the optimum impedance-matching design from the viewpoint of high-speed interconnection between LD and driver ICs. As for the APD receiver, the key issue is input impedance design of preamplifier IC, considering noise and bandwidth characteristics. Total performance of the transmitter and receiver is verified by a 10-Gb/s transmission experiment and a penalty-free 10-Gb/s fiber-optic link over 80 km of conventional single-mode fiber is successfully achieved. >

An optical bit-rate flexible transmission system with 5-Tb/s-km capacity employing multiple in-line erbium-doped fiber amplifiers

An optical bit-rate flexible transmission system using erbium-doped fiber amplifiers (EDFAs) is proposed, and the system design is discussed. An optical bit-rate flexible system using multiple in-line erbium-doped fiber amplifiers has produced a regenerative repeater spacing of 505 km at 10 Gb/s and 523 km at 5 Gb/s for direct-detection systems. This system proves that an optical bit-rate flexible system with a transmission capacity of 5.05 Tb/s-km can be feasibly constructed. System capacity is clarified both theoretically and experimentally. The power penalties involved are discussed. The related optical and electrical circuits proved operational above 10 Gb/s. The 523 km at 5 Gb/s and 505 km at 10 Gb/s transmission experiments successfully demonstrated that EDFAs effectively enhance a systems transmission capacity. >

Terabit LAN with optical virtual concatenation for Grid applications with super-computers

This paper proposes an optical local area network that can transmit terabit-class bulk-data with low latency in a dynamic manner. A group of wavelengths is assigned to bulk-data transmission according to the latency requirement, and parallel WDM signals are transmitted with bit-phase synchronization mechanism after fast provisioning.

A 212 km NON-REPEATED TRANSMISSION EXPERIMENT AT 1.8 Gb/s USING LD PUMPED Er3+-DOPED FIBER AMPLIFIERS IN AN IM/DIRECT-DETECTION REPEATER SYSTEM

Over the past several years, non-repeated transmission distances using coherent detection have been longer than those using direct detection. It is noticed that minimum detectable photon numbers of the direct detection schemes are no more than those of the coherent schemes, under shot-noise limited condition. Optical amplification techniques play important roles to improve the receiver sensitivity in the direct detection system [1] and to increase the fiber launched power.

Forward error correcting codes in synchronous fiber optic transmission systems

This paper proposes forward error correcting (FEC) code for synchronous digital hierarchy (SDH) fiber optical transmission systems. They are (18880, 18865) and (2370, 2358) shortened Hamming codes and are encoded at the multiplex-section layer; the check bits are embedded in auxiliary multiplex-section overhead (MSOH) bytes. The codes realize general circuit configurations regardless of the transmission speed or path-size, perfect compatibility with SDH format, suppressed processing delay accumulation, and decrease the chance of line-switching in the case of signal degradation. To ensure that the various requirements of each network-provider such as customized usage of SOH bytes and affordable circuit scale could be satisfied, a trial circuit board was constructed on the programmable hardware called PROTEUS, which enables flexible operation in terms of code-selection and check bit area. We actually confirm error-correcting capability through the first STM-64 FEC-coded-optical transmission experiment. The statistics of error occurrence in the optical transmission line are also studied. The result indicates that the proposed codes are effective in optical transmission systems if the BER is limited by optical noise and dispersion.

Long-span repeaterless transmission systems with optical amplifiers using pulse width management

This paper proposes pulse width management in order to extend the repeater spacings of repeaterless transmission systems with optical amplifiers. First, the dependency of receiver sensitivity on duty ratio, receiver response, and fiber dispersion is clarified by numerical analysis. Next, the calculation results of sensitivity as a function of signal format and receiver basedband response are verified experimentally. Moreover, we show that pulse width management which uses return-to-zero (RZ) format with large duty ratio (/spl sim/0.7) at the transmitter and pulse compression at the receiver increases the repeater gain by /spl sim/4.5 dB compared to conventional systems employing nonreturn-to-zero (NRZ) format. Record repeater spacing of 300 km is realized at 10 Gb/s by utilizing pulse width management.