Inha-industry Partnership Institute

Gwangju Institute of Science and Technology

Byoung-Seung Ham

A system, method, and apparatus for delayed optical logic gates based on slow light and enhanced nondegenerate four-wave mixing processes, where a single or multiple delayed optical routers are utilized for dark resonance interactions in which two-color lasers interact with a three-level nonlinear optical medium comprised of two ground states and one excited state through the nondegenerate four-wave mixing processes. The delayed optical logic mechanism is based on combination of single or multiple dark resonance-induced two-photon coherence conversion via slow light phenomenon. The two-photon coherence induced on the ground states is optically detected via nondegenerate four-wave mixing processes. The nondegenerate four-wave mixing generation is enhanced owing to dark resonance or electromagnetically induced transparency. The delayed optical logic gates have potential to keep up ultra-high-bandwidth optical information processing using relatively slow electronic processing devices.

Delayed optical logic gates for boolean algebra

A system, method, and apparatus for delayed optical logic gates based on slow light and enhanced nondegenerate four-wave mixing processes, where a single or multiple delayed optical routers are utilized for dark resonance interactions in which two-color lasers interact with a three-level nonlinear optical medium comprised of two ground states and one excited state through the nondegenerate four-wave mixing processes. The delayed optical logic mechanism is based on combination of single or multiple dark resonance-induced two-photon coherence conversion via slow light phenomenon. The two-photon coherence induced on the ground states is optically detected via nondegenerate four-wave mixing processes. The nondegenerate four-wave mixing generation is enhanced owing to dark resonance or electromagnetically induced transparency. The gating time and bandwidth of the present delayed optical logic gates is invariant to the delayed time of the delayed optical router because IN and OUT bandwidth across the nonlinear medium must be same.

Delayed optical logic gates

A system, method, and apparatus for delayed optical router based on slow light and nondegenerate four-wave mixing processes are presented, in which three laser pulses interact with a three-level nonlinear optical medium composing two closely spaced ground states and an excited state. The delayed optical routing mechanism is based on a slow light phenomenon, in which a group velocity of an incoming input signal pulse is slowed down due to quantum coherence induced refractive index change. The two-photon coherence induced on the ground states via electromagnetically induced transparency is optically recovered via nondegenerate four-wave mixing processes. The nondegenerate four-wave mixing generation is enhanced owing to absorption cancellation. In this case, the individual pulse switching/routing time is limited by the coherence decay time that is much faster than population decay time, where the population decay-time is a limiting factor of conventional switching devices. In the present invention of the delayed optical router the overall switching/routing time, however, is controlled to be delayed by using the slow light. Even though the overall switching/routing time can be delayed, the switching bandwidth of the present invention is not degraded at all because the input and output signal's group velocity across the delayed optical router is still same. Therefore, the present invention of the delayed optical router gives an advantage of wide-bandwidth optical data traffic control using a narrow-bandwidth processing unit such as an electronic device. Another advantage is signal amplifications owing to the dark-resonance enhanced nondegenerate four-wave mixing processes.

Delayed optical router/switch

The present invention provides a quantum optical data storage protocol, whose storage time is lengthened by spin population decay time from several minutes to several hours. The quantum data storage includes a first ground state and a second ground state which are closely spaced each other in energy level or degenerated and to forbid two-photon transitions between the first and second ground states; an excited state which has a spin inhomogeneous broadening and to allow two-photon transitions between the first ground state and the second ground sate via the excited state and allow a spin coherence; an auxiliary state for forbidding two-photon transitions between the first and second ground states via the auxiliary state and allowing a transition from/to the excited state; wherein a spin coherence induced by a transition of two photons from the first ground state and the second state to the excited state is transited to the auxiliary state so that a phase decay of the spin coherence is prevented and data is stored as the phase of the spin coherence.

Growing community of inventors

Incheon, South Korea

Byoung-Seung Ham