Patent ID: 7755821
Filing Date: 2010-07-13
Classification: B82Y,G02F,G06E,G06N

Abstract:
1. A method of photon logic gates using a single or multiple quantum switches whose nonlinear optical medium is comprised of three closely spaced ground states | 1 >, | 2 > and | 3 > such that the transition among the said ground states is dipole forbidden, and an excited state | 4 > and | 5 > such that two-photon transitions between said ground state | 1 > and said | 3 >, said | 2 > and said | 3 >, and said | 1 > and said | 2 > via said excited state | 4 > (and said excited state | 5 > if said | 5 > is real energy state) are allowed, said method comprising following steps: a) applying to said nonlinear optical medium a first laser beam as an input beam A through an optical waveguide or free space at a frequency of ω b) applying a second laser beam C through an optical waveguide or free space at a frequency of ω c) applying a third laser beam S through an optical waveguide or free space at a frequency of ω d) applying a fourth laser beam R through an optical waveguide or free space at a frequency of ω e) adjusting the intensities of said first laser beam A, said second laser beam C, said third laser beam S, and said fourth laser beam R to produce nondegenerate four-wave mixing signals Q f) connecting said nondegenerate four-wave mixing signals Q g) connecting two quantum switches in a way to share said S and combine each said Q h) connecting two quantum switches in a way to combine nondegenerate four-wave mixing signals Q i) connecting said Q j) connecting each said Q