Optically differential reconfigurable gate array

Recent years have seen the development of optically reconfigurable gate arrays, which can be reconfigured using light at high speeds that cannot be implemented with electrical wiring. However, optically reconfigurable gate arrays have reconfiguration speeds of 16 to 20 mu s, which is fast compared to FPGAs (Field Programmable Gate Arrays), but high-speed reconfiguration, approaching the operating clock of a mounted circuit, has not been implemented. Also, partial reconfiguration, which is indispensable for frequent dynamic reconfiguration, has not been considered. The authors propose an Optically Differential Reconfigurable Gate Array (ODRGA), which can be reconfigured at high speeds close to the operating clock of a mounted circuit and which allows partial reconfiguration of any zone in bit units. This paper includes an overview of ODRGA and introduces the optically differential reconfigurable architecture, with which arbitrary, partial reconfiguration is possible, as well as the optically reconfigurable architecture enabling highspeed optical reconfiguration. Then, it is demonstrated that high-speed optical reconfiguration at 200 ns, the world's fastest system-level optical reconfiguration, is possible with an optical system using a pulse laser diode wherein nanosecond optical reconfiguration is possible with a prototype stand-alone VLSI chip. Finally, it is made clear that, in the future, improvement to the optical components will make possible nanosecond high-speed optical reconfiguration at the system level as well. (C) 2007 Wiley Periodicals, Inc.