1 July 1990 Optically switched lithium niobate directional couplers for digital optical computing
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Proceedings Volume 1215, Digital Optical Computing II; (1990) https://doi.org/10.1117/12.18082
Event: OE/LASE '90, 1990, Los Angeles, CA, United States
Optically switchable directional couplers can function as logically complete building blocks for constructing all-optical computational engines. Logically, such devices operate as all-optical five-terminal gates, where two output signals are logical functions of two guided input signals and an input control signal. Such an optically controlled exchange element is a promising functional unit for constructing general-purpose digital optical logic circuits. We have implemented such all-optical five-terminal gates using Ti:LiNbO eleciro-optic directional couplers, with singlemode optical fiber for all gate interconnections. Effectively DC-coupled control circuitry converts short, low-power (<5ns, -25 dBm) 1 .3 mm optical pulses into electrical pulses capable of switching the transfer state of low-voltage lumped electrode directional couplers. These optical logic gates, while containing significant electronics in the control arm, are logically identical to more fundamental optically controlled exchange elements, and utilize mature technology developed for the optical fiber telecommunications industry, simplifying construction of robust optical logic hardware. In addition, the use of significant electronics in the control terminal input offers considerable advantages over more fundamental optical switching effects, i.e. greater noise immunity, wider dynamic range, adjustable detection threshold, simple phase compensation, and conirol over the quiescent switching state. We have demonstrated the use of such Ti:LiNbO3 five-terminal optical logical gates in the construction of various simple circuits, such as oscillators and divide-by-N circuits. Such circuits demonstrate many of the issues arising in the construction of all-optical digital computing systems, and are fundamental subsections of an all-optical bit serial computer design, which we are currently consiructing.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alan F. Benner, Harry F. Jordan, Vincent P. Heuring, "Optically switched lithium niobate directional couplers for digital optical computing", Proc. SPIE 1215, Digital Optical Computing II, (1 July 1990); doi: 10.1117/12.18082; https://doi.org/10.1117/12.18082

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