USA As Represented by Secretary of the Navy

Markham E Lasher

Mark W Roberts

Stephen Douglas Russell

David W Brock

Shannon D Kasa

Weldon J Dahlke

Narayan R Joshi

Debra M Gookin

Mark H Berry

In various embodiments, a secure optical communication system is disclosed. Such a system may include a photon-pair generation circuit configured to generate pairs of photons with each photon pair including a first-channel photon and a second-channel photon, a transmitting circuit configured to receive first-channel photons, and modulate the first-channel photons according to a stream of data using a first optical circulator to produce first-modulated photons, and a receiving circuit configured to receive second-channel photons, pass the second-channel photons through a complementary optical circulator to produce second modulated photons, and detect relative timing between the first-modulated photons and the second modulated photons to recover the stream of data.

Secure optical communication system

An optical communication system is provided. In one embodiment, a source creates a multiplicity of photon pairs, with each photon pair comprising a first photon and a second photon. The first photon is sent to a transmitter, and either remains in the transmitter or is transmitted by the transmitter to a receiver. The second photon is sent to the receiver. Data is decoded by determining a polarization direction and a time of detection of any photon pairs detected at the receiver.

Secure quantum optical communications system and method

A Quantum Dense Coding System. The system includes a source, a transmitter and a receiver. The source is capable of down-converting a pump photon into a signal photon and an idler photon and outputting probability amplitudes, the signal photon and the idler photon, wherein the signal photon and the idler photon have an equal probability of outputting to a transmission channel and a reception channel. The transmitter is capable of receiving probability amplitudes, signal photons and idler photons from the transmission channel; and selectively changing vertical and horizontal phases of probability amplitudes of signal photons and idler photons; and outputting probability amplitudes, signal photons and idler photons. The receiver is capable of receiving probability amplitudes, signal photons and idler photons from the reception channel and the transmitter; and identifying vertical and horizontal phase changes created by the transmitter. A method for the system is also described.

Quantum dense coding system

A system parametrically down-converts a photon into a pair of first and second quantum-entangled photons. A transmitter is coupled to receive the first photon and includes an irreversible collapse event device for collapsing the quantum-entangled state of each photon in the pair. The collapse is caused by attempting to detect the first photon at the transmitter. Because of quantum-entanglement, collapse of the first photon collapses the second photon of the pair. The transmitter can also be used to not cause the collapse. A receiver includes polarization detectors to detect whether the transmitter has collapsed or left uncollapsed the quantum-entangled state of the photon pair. Causing or not causing the collapse can be used for communication. Every down-converted photon can be used for communication, even though few of the photons actually leave the source and reach the transmitter. This allows communication with a minimal number of transmitted photons.

Minimum transmitted photon quantum optical communications system

A communication system employs quantum entanglement by projecting photons through a nonlinear crystal. Some become parametrically down-converted into signal and idler photon pairs. The signal photons are projected to a receiver and the idler photons to a transmitter. The transmitter operator can alter the time width and a majority of the center wavelengths of the idler photons via a collapse event in the transmitter. Because of quantum entanglement, a corresponding change in the time width and center wavelengths of the signal photons as received at the receiver results. The purposeful causation of the collapse event or a lack of such purposeful causation can be used for binary communication. In addition, the sensing of an atmospheric condition may be performed by equating changes in received signal photon characteristics with changes in collapse conditions in the atmosphere.

Quantum optical communications system

An electromagnetic sensor system. The system includes an electromagnetic excitable structure that generates an acoustic signal when irradiated with electromagnetic energy; an acoustic energy transducer sensor for generating a first output signal that represents the acoustic signal in response to the acoustic energy transducer detecting the acoustic signal; and a processor for determining whether the electromagnetic excitable structure is being irradiated by the electromagnetic energy in response to the processor receiving the first output signal.

Electromagnetic sensor system and method

A nondestructive acoustic emission testing system using electromagnetic excitation, comprises: a) an electromagnetic wave generator for generating electromagnetic waves that stimulate a test sample to generate acoustic energy; b) an acoustic energy sensor for detecting the acoustic energy and generating a first output signal that represents the acoustic energy; and c) a data processor for comparing the output signal with a reference and for generating a second output signal that represents a characteristic of the test sample.

Nondestructive acoustic emission testing system using electromagnetic excitation and method for using same

A system for alternately directing optical energy through multiple optical modulation channels includes an optical switch having first and second optical output ports for alternately directing an optical signal at full input power out of first and second optical output ports; a first optical modulation channel for modulating the output signal received from the first optical output port; and a second optical modulation channel for modulating the output signal received from the second output port. The optical switch includes a Pockels cell and a birefringent mirror. The Pockels cell transforms a first polarization state of the optical signal into a second polarization state in response to receiving an input signal. The birefringent mirror allows the optical signal to propagate along a first axis when the optical signal has a first polarization state, and directs the optical signal along a second axis when the optical signal has a second polarization state.

System for alternately directing optical energy through multiple optical modulation channels

A sequential color scanner capable of generating both two and three dimensional moving color images has only one x- and y-deflection channel. The system includes first, second, and third optical signal generators for generating a first, second, and third optical signal, respectively. Each optical signal is characterized one of the three primary colors. The first, second, and third light signals are blue, green, and red, although not necessarily in that order. The first optical signal is generated along an optical axis. First and second beam combiners direct the second and third optical signals, respectively, along the optical axis. A first optical deflector deflects the optical signals in a first plane, and a second optical deflector for deflecting the optical signals in a second plane that is orthogonal to the first plane. First, second, and third modulators modulate the intensity of the first, second, and third optical signals, respectfully. A controller supervises each of the first, second, and third modulators so that the optical signals are generated in a pulsed, repeating sequence in accordance with an index that is counted by an index counter implemented in a controller. The controller also supervises modulation of the first and second optical deflectors so that the light signals are directed to predetermined coordinates. A time delay &tgr; is introduced between optical signals for enhancing the sharpness of the image by assuring that the optical deflectors modulate only one light signal at a time.

Sequential color scanner

An optical crossbar switch includes a plurality of input integrated optical couplers connected to a star coupler at one end of an optical cable and a star coupler coupled to the other end of the optical cable connected to plurality of output integrated optical couplers. Discrete parallel optical input signals are fed to each of the input integrated optical switches and clock signals in a time division multiplexed switching sequence switch the parallel optical signals to serial form for transmission over the cable. Clock signals are connected to actuate the output integrated optical couplers in a synchronized, time division multiplexed switching sequence at GHz rates to assure the responsive transfer of a number of signals without the consequences associated with the excessive losses attendant conventional spatial light modulator interconnections.

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La Jolla, CA, United States of America

Markham E Lasher