Water Polution & Bio Sensor

       The performance requirements of computer, telecommunication and data-communication systems have increased considerably in recent years to a point at which large-scale electronic systems now suffer an interconnection bottleneck. The backplane bus traffic increases greatly with the computing power of the microprocessors, creating a major bottleneck due to limited bus bandwidth. In the conventional electrical backplane, the bandwidth of communication path or bus is limited by signal propagation delay, skew, power consumption, and capacitive effects. To remove the interconnect bottlenecks, Omega Optics Inc has been developing an evenly broadcasted optical backplane bus using volume holograms based on guided wave optical interconnects. The proposed guided-wave optical backplane provides the optical path by total internal reflection within the plane-parallel glass plate. In this scheme, the electrical connectors are positioned as usual, and the active optoelectronic modules including transmitters and receivers are placed on the bottom of the backplane board. Thus, insertion or removal of circuit boards during operation does not affect their alignment.
       Typical backplane bus and personal computer memory bus operate at a frequency of 133MHz but the processors are reaching speeds of beyond 2GHz. The trend of computing speed outpacing the interconnect speed will be more serious in the near future. In a standard backplane interface that simplifies integration of data processing, data storage, and peripheral devices in a tightly coupled hardware configuration, for example, in VME bus and PCI bus, the bus width varies from16-bit to 64-bit, but the maximum bandwidth per channel remains 133Mbit/sec. Although the aggregate throughput has increased four times using multiple bus lines compared to earlier VME bus and PCI bus, one cannot expect to increase the bus width more and more. Therefore, it is necessary to search the backplane implementation technologies for higher bandwidth, not bus width.
       In our optical backplane (Figure), the conventional electrical connectors are positioned as usual, and the active optoelectronic modules including transmitters and receivers are placed on the bottom of the backplane board. Thus the insertion or removal of circuit boards during the normal operation does not affect their alignment. This approach also provides bi-directional signal broadcasting capability, which means any board can send and receive the signals. In this way, the proposed high performance optical backplane system can substitute for existing electrical backplanes (for example, CompactPCI and VME bus) for intra-system data transfer with upgraded data transfer rate of 2.5Gpbs.