ALL-OPTICAL NOT/XOR, AND NAND GATES, ALL-OPTICAL BISTABLE, ASTABLE MULTIVIBRATORS AND ALL-OPTICAL HALF ADDER USING NOVEL ALL-OPTICAL SWITCHING IN A MACH-ZENDER INTEROFEROMETER

摘要

Thus, the present invention proposes a method of obtaining all-optical switching in a Mach-Zehnder Interferometer (MZI) which essentially comprises a Y-Junction/Directional coupler at the input end of the MZI and a Y-Junction at the output end of the MZI. The proposed switch (with the new method of switching) is capable of functioning with the same/different wavelength of signal and switching beams. Moreover, the switch can function with equal intensities and same wavelength of mutually incoherent signal and switching beams. Such a switch is also "passive" as no active component is required within the architecture of the switch. Adapting the novel method of switching, it is possible to obtain All-Optical analog of conventional electronic NOT/XOR, AND and NAND Gates. And using these gates it is further possible to construct All-Optical analog of Bistable Multivibrators, Astable Multivibrators and Half Adder. Accordingly, there is provided a MZI with a first arm made up of a nonlinear material and a second arm with linear material. A Y-junction or a directional coupler is provided at the input end of the MZI to have two input ports P1 and P2 and a Y-Junction at the output end to have one output port Po. When the selected Input intensity is launched at any one of the input ports, it equally splits and propagates through the each arm of the interferometer and recombines at the Y-Junction provided at the output of MZI. If the splitted signals recombine with "in-phase" condition, the input intensity reaches at the output port (Po) giving "HIGH" output and if splitted signals recombine with "out-of-phase" condition, the input intensity doesn"t reach at Po giving "LOW" output. One can set the parameters of the MZI so that the output is HIGH only when one of the two inputs ports is provided with the selected light intensity. One can also set parameters so that the output is HIGH only when both of the two inputs ports are provided with the selected light intensities.