© 2003 OSA/OC 2003 PDP2-1 Ultra-fast All-Optical LOGIC GATES for optical computing Hossin, Abdeldayem 1 , Donald 0. Farzier 2 , Benjamin G. Penn 2 , and Mark S. Paley 2 ; NASA-GSFC, USA 1 , hossin.abdeldayem@nasa.gov NASA-MSFC, USA 2 . Summary Future communication and computation problems are inevitable since conventional electronics technology will very soon reach its ultimate speed limit. Therefore, a drastic solution to the problem is needed, and unless we adjust our thoughts to a totally different direction from the conventional electronics, we will not be able to further improve our computer performance for the future, nor will we be prepared for the challenges of space exploration. Optical interconnections and optical integrated circuits are strongly believed to be the most feasible technology that can provide the way out of the extreme limitations imposed on the speed and complexity of present-day computations by conventional electronics. Optical devices have been incorporated into many and proved to be reliable and more advantageous. Optics provides higher bandwidth than electronics, which enables more information to be carried simultaneously and data to be processed with ease in parallel. Optical signals in fibers, integrated circuits, and free space do not have to charge a capacitor and are therefore faster. The photons can cross each other without interference and are immune to space radiation. Such advantage of optical data processing is of extreme interest to the avionics divisions at NASA, and the defense industry, where there will be no need for radiation shielding. An obvious advantage of optical over electronic computing is that optical signal processing promises an impressive increase in speed by several orders of magnitude over conventional electronic signals. This parallelism if associated with fast switching speed would result in a staggering computational speed. For example, if a 100 million gates on a chip (Pentium III microprocessor has -140 million gates) were made optically and assuming on the conservative side each one is operating with a switching time of only 1 ns, the system could perform more than 10 17 bit operations per second. Compare this to the speed rate of giga (10 9 ) bits per second which the