Shigeto Akutsu

Quantum Encryption Communication Over a 192-km 2.5-Gbit/s Line With Optical Transceivers Employing Yuen-2000 Protocol Based on Intensity Modulation

A Y-00 transceiver for quantum encryption communication systems employing the Yuen-2000 protocol based on optical intensity modulation, which utilizes the quantum effect of coherent light has been developed and tested in field experiments. These experiments involved repeated transmission over a 192-km line on an existing commercial optical communication network with a bit-rate of 2.5 Gb/s based on STM-16 or OC-48. In addition, the affinity of the developed system for existing networks and communication protocols (Gigabit Ethernet and Fibre Channel) was examined. Subsequently, three optical fiber amplifiers were inserted as intermediate repeaters to give a non-repeated transmission distance of 48 km. The bit error rate after 192-km transmission was 10-12 with an optical power of -19.4 dBm at the receiving end. In addition, it was confirmed that if an eavesdropper increased the received optical power, the bit error rate converged to about 5 × 10- 1 and the identification of the true signal levels was virtually impracticable. These experimental results confirmed the high affinity between the Y-00 system and existing optical commercial networks and protocols used in the fundamental experiments. It was also apparent that the realization of highly secure optical communication networks was feasible. The performance of the Y-00 transceiver can be expected to improve to meet the strictest security evaluation.

RHiNET-3/SW: an 80-Gbit/s high-speed network switch for distributed parallel computing

We have developed a prototype network switch, RHiNET-3/SW, for a RHiNET high-performance distributed parallel computing environment. It has eight I/O ports and each port provides high-speed, bi-directional 10-Gbit/s-per-port parallel optical data transmission in a distance of over 300 m. The aggregate throughput is 80 Gbit/s per board. A switch consists of a one-chip CMOS ASIC 8/spl times/8 switch LSI (SW-LSI; a 784-pin BGA package), four deskew LSIs, and eight pairs of 1.25-Gbit/s/spl times/12-channel optical interconnection modules on a single board. The switch uses a hop-by-hop retransmission mechanism and credit-based flow control to provide reliable and long-transmission-distance data communication. The deskew LSI has a skew compensation function for 10-bit parallel data channels and an 8B10B encoder/decoder. Its optical transmitter modules use an 850-nm VCSEL and a 12-channel MMF (multi-mode fiber) ribbon. RHiNET-3/SW enables high-throughput. Long-distance and flexible-flow-control network communication by means of distributed parallel computing using commercial PCs.

10-Gb/s Optical Transceiver Using the Yuen 2000 Encryption Protocol

A 10-Gb/s optical transceiver using the Yuen 2000 (Y-00) encryption protocol was developed. The key device in the transceiver, a 10-GS/s, 10-bit digital-to-analog converter (DAC) LSI, was fabricated using 0.25-μm SiGe BiCMOS technology. Circuit techniques such as segmented architecture, parasitic capacitance separation using the base-common transistor, and the usage of a common mode logic (CML) driver were employed to minimize glitches. The Y-00 transceiver equipped with the DAC LSI operated at 10 Gb/s. Moreover, a 300-km transmission experiment performed at a data rate of 10 Gb/s proved that the developed transceiver can be used in a practical application when forward error correction is applied.

64-Gb/s highly reliable network switch (RHiNET-2/SW) using parallel optical interconnection

RHiNET-2/SW is a network switch that enables high-performance optical network based parallel computing system in a distributed environment. The switch used in such a computing system must provide high-speed, low-latency packet switching with high reliability. Our switch allows high-speed 8-Gb/s/port optical data transmission over a distance of up to 100 m, and the aggregate throughput is 64 Gb/s. In RHiNET-2/SW, eight pairs of 800-Mb/s/spl times/12-channel optical interconnection modules and a one-chip CMOS ASIC switch LSI (a 784-pin BGA package) are mounted on a single compact board. To enable high-performance parallel computing, this switch must provide high-speed, highly reliable node-to-node data transmission. To evaluate the reliability of the switch, we measured the bit error rate (BER) and skew between the data channels. The BER of the signal transmission through one I/O port was better than 10/sup -11/ at a data rate of 800 Mb/s /spl times/10 b with a large timing-budget margin (870 ps) and skew of less than 140 ps. This shows that RHiNET-2/SW can provide high-throughput, highly reliable optical data transmission between the nodes of a network-based parallel computing system.

360km field transmission of 10 Gbit/s stream cipher by quantum noise for optical network

Secure optical transmission experiment is demonstrated using a stream cipher by quantum noise. The bit error rates of a 10 Gbit/s signal through 360 km fiber for authentic receiver and eavesdropper are 5×10-7 and 0.4 ~0.5.

High-throughput network switch for the RHiNET-2 optically interconnected parallel computing system

We have produced a prototype network-switch board (the RHiNET-2/SW) for optical interconnection. Eight pairs of 800-Mbit/s X 12-channel optical interconnection modules and a one-chip CMOS ASIC switch LSI (a 784-pin BGA package) are mounted on to a single board. This board allows 8- Gbit/s/port parallel optical data transmission over a distance of up to 100 m, and the aggregate throughput is 64 Gbit/s/board. All of the electrical interfaces are composed of CMOS-LVDS logic. We have evaluated the skew of the signal and the reliability of each optical port by measuring the BER. No errors were detected during the 1011-bit packet data transmission at a data rate of 880 Mbit/s X 10 bits (8.8 Gbit/s/port). (This corresponds to a BER of less than 10-11). The skew between data channels in one I/O port was less than 141 ps. The fiber length was 50 m. This test result shows that we achieved a high-throughput and long-transmission-length RHiNET-2/SW system using optical interconnection, and that the reliability of the I/O ports in the RHiNET-2/SW is sufficient for the RHiNET-2 parallel computing system.

192 km relay transmission and HDTV transmission experiments by Quantum Yuen‐2000 transceiver

We are concerned with the realization of high speed secure communication system which is an urgent desire from the data center system. It has been proved that a quantum stream cipher by Yuen 2000 protocol (so called Y‐00 or αη) has remarkable security under quantum individual attack. So it is very attractive in implementing 1∼10 G bit/sec optical data center communication system. This paper introduces a system with some randomizations to reinforcement of the security in future implementation. Furthermore, we report the data transmission of 2.5 Gbit/sec in the real commercial network of 192 Km in Tokyo, and also a demonstration of High Definition Television (HDTV: 1.4 Gbit/sec) transmission of 40 Km by 2.5 Gbit/sec transceiver based on the basic model, which is immediately applicable to medical and broadcasting system.