Abstract: The disclosure provides a straight waveguide phase change all-photonic Boolean logic device and a full binary logic implementation method thereof, including a ridge- shape straight waveguide structure, two phase change functional units near the two ends and a Bragg grating between two phase change functional units. The phase change functional units and Bragg grating are situated on the ridge of the waveguide. The write and read optic pulses have different wavelengths. The Bragg grating are designed to reflect the write optical pulse and transmit the read pulse, so that write pulses input from the two ends only act on the phase change functional unit closest to that end, and read pulse can go through the whole device from input end to output end. In terms of the logic implementation method, with three-step write operation, 16 full Boolean logic functions can be implemented in this device.

Abstract: A method of performing simultaneous entangling gate operations in a trapped-ion quantum computer includes selecting a gate duration value and a detuning frequency of pulses to be individually applied to a plurality of participating ions in a chain of trapped ions to simultaneously entangle a plurality of pairs of ions among the plurality of participating ions by one or more predetermined values of entanglement interaction, determining amplitudes of the pulses, based on the selected gate duration value, the selected detuning frequency, and the frequencies of the motional modes of the chain of trapped ions, generating the pulses having the determined amplitudes, and applying the generated pulses to the plurality of participating ions for the selected gate duration value. Each of the trapped ions in the chain has two frequency-separated states defining a qubit, and motional modes of the chain of trapped ions each have a distinct frequency.

Abstract: A method of performing simultaneous entangling gate operations in a trapped-ion quantum computer includes selecting a gate duration value and a detuning frequency of pulses to be individually applied to a plurality of participating ions in a chain of trapped ions to simultaneously entangle a plurality of pairs of ions among the plurality of participating ions by one or more predetermined values of entanglement interaction, determining amplitudes of the pulses, based on the selected gate duration value, the selected detuning frequency, and the frequencies of the motional modes of the chain of trapped ions, generating the pulses having the determined amplitudes, and applying the generated pulses to the plurality of participating ions for the selected gate duration value. Each of the trapped ions in the chain has two frequency-separated states defining a qubit, and motional modes of the chain of trapped ions each have a distinct frequency.

Abstract: A method of performing a computation using a quantum computer includes generating a plurality of laser pulses used to be individually applied to each of a plurality of trapped ions that are aligned in a first direction, each of the trapped ions having two frequency-separated states defining a qubit, and applying the generated plurality of laser pulses to the plurality of trapped ions to perform simultaneous pair-wise entangling gate operations on the plurality of trapped ions. Generating the plurality of laser pulses includes adjusting an amplitude value and a detuning frequency value of each of the plurality of laser pulses based on values of pair-wise entanglement interaction in the plurality of trapped ions that is to be caused by the plurality of laser pulses.

Abstract: An optical logic device includes a distributed feedback laser configured to generate a first signal corresponding to distributed feedback laser output signal, the first signal being at a first wavelength. The device further includes a bandpass filter having a center frequency corresponding to the first wavelength. Additionally, the device can include an optical circulator having a first port coupled to a logic device input signal, a second port coupled to the first signal, and a third port coupled to the bandpass filter, wherein when the logic device input signal has a power above a predetermined threshold and there is a wavelength difference between the first wavelength and an input wavelength of the logic device input signal, a suppression of the first signal occurs.

Abstract: An optical logic device includes a distributed feedback laser configured to generate a first signal corresponding to distributed feedback laser output signal, the first signal being at a first wavelength. The device further includes a bandpass filter having a center frequency corresponding to the first wavelength. Additionally, the device can include an optical circulator having a first port coupled to a logic device input signal, a second port coupled to the first signal, and a third port coupled to the bandpass filter, wherein when the logic device input signal has a power above a predetermined threshold and there is a wavelength difference between the first wavelength and an input wavelength of the logic device input signal, a suppression of the first signal occurs.

Abstract: Aspects of the disclosure involve a source node, having some predetermined knowledge of the optical network generating a list of nodes and/or optical links between nodes that form a route in the optical network from the source node to the destination node. The nodes in the optical network do not necessarily need to know the entire route from source node to destination node. Each node simply decodes the control information identifying the next hop in the route towards the destination node. By utilizing the decoded control information identifying the next hop, a switch in the node can be controlled to route the optical signal including the payload and some or all of the control information onto the next optical link toward the destination node.

Abstract: An optical logic circuit includes a NOT circuit. The NOT circuit reflects by fixed end reflection an data pulse input into the optical logic circuit which is an ON pulse of which a wavelength and an intensity are similar to a wavelength and an intensity of a standard optical pulse or an OFF pulse obtained by applying OFF modulation to the standard optical pulse. The NOT circuit multiplexes the reflected data pulse and the standard optical pulse and outputs the multiplexed pulse.

Abstract: Systems, methods, and devices relating to reconfigurable antennas are disclosed.

Abstract: A photonic crystal all-optical D-type flip-flop includes an optical switch unit, a photonic crystal structure unit including two signal-input ends, a signal-output end and an idle port, a wave absorbing load and a reference-light source; the clock signal-input port of the photonic crystal structure unit is connected with a clock control signal; a second port of the photonic crystal structure unit is an intermediate signal-input port, said intermediate signal-input end of the photonic crystal structure unit is connected with a first intermediate signal-output end of the optical selector switch; a logic signal is connected with the first signal-input end of the optical switch unit; the absorbing load is connected with a second intermediate signal-output end of the optical switch unit; said reference-light source is connected with a second signal-input end of the optical switch unit, which is a reference-light input end connecting with the output end of said reference-light source.

Abstract: A PhC all-optical multistep-delay OR-transformation logic gate includes an optical switch unit having a first intermediate-signal output port, a PhC structure unit having a first intermediate-signal input port connected with the first intermediate-signal output port, a reference-light source connected with the reference-light input port of the optical switch unit, a wave absorbing load, a flip-flop unit, and a memory or delayer having an input port connected with a first logic signal and an output port connected with the delay-signal input port of an optical switch unit whose logic-signal input port is connected with a second logic signal; a second intermediate-signal input port of the PhC structure unit is connected with the second intermediate-signal output port of said optical switch unit; a third intermediate-signal output port of the optical switch unit is connected with the wave absorbing load; a clock control-signal is input through the input port of a two-branch waveguide.

Abstract: Graphene may support electromagnetic radiation and be able to support a variety of optical devices. In general, graphene may exhibit changeability in properties such as the conductivity and the like of graphene. Graphene may comprise carbon and be of a thickness of a single atomic layer. In another embodiment, Graphene may be thicker than a single atomic layer, but may be able to exhibit changeability in the properties noted above. Disclosed herein is the guiding and manipulating of optical signals on layers of graphene to create waveguides, ribbon waveguides, beamsplitters, lenses, attenuators, mirrors, scatterers, Fourier optics, Luneburg lenses, metamaterials and other optical devices.

Abstract: A photoreceiver device includes a light detector connected between a power supply node and a first node, and first to third switching elements. The light detector is configured to detect an incident optical data signal, and to output photocurrent corresponding to a magnitude of the optical data signal through the first node. The first switching element is connected between the first node and a ground node. The second switching element is connected between the power supply node and a second node. The third switching element is connected between the second node and the ground node. The third switching element has a control node connected to the first node.

Abstract: An illumination system includes a first light source module and a first reflective mirror module. The first light source module includes plural first light sources for emitting plural first light beams, respectively. The first reflective mirror module includes at least one first reflective mirror, at least one first fixing structure, and at least one first adjusting mechanism. The first reflective mirror is located at a first optical axis of the plural first light sources. The at least one first fixing structure is used for fixing the first reflective mirror. The first adjusting mechanism is connected with the first fixing structure. By moving or rotating the first adjusting mechanism, a location and an angle of the first reflective mirror relative to the first optical axis are correspondingly changed, so that the first light beam is reflected by the first reflective mirror and guided along a specified optical path.

Abstract: Provided are an optical switch and an optical logic device. The optical switch includes a plate having a nanometer-sized thickness, a first slit formed in the plate, through which a first light passes, a second slit formed in the plate, separately from the first slit, through which a second light selectively passes, a plurality of first grooves formed on a first side of the first slit, between the first slit and the second slit, and a plurality of second grooves formed on a second side of the first slit, opposite the first side. The first light and the second light may have a phase difference and a focusing of the first light is turned on/off by controlling the second light.

Abstract: A variable optical attenuator is provided. The variable optical attenuator includes an input optical fiber, an output optical fiber, a non-attenuating, transmission-type diffracting prism and a prism positioning system. The input optical fiber, the non-attenuating, transmission-type diffracting prism and the output optical fiber are optically arranged such that an optical path from the input core of the input optical fiber to the output core of the output optical fiber passes through the non-attenuating, transmission-type diffracting prism. The non-attenuating, transmission-type diffracting prism diffracts an optical signal propagating from the input optical fiber to the output optical fiber such that an input portion of the optical path is non-linear with an output portion of the optical path. The prism positioning system changes a pose of the non-attenuating, transmission-type diffracting prism within the optical path thereby attenuating the optical signal.

Abstract: The present disclosure is a novel utility of a software defined radio (SDR) based Distributed Antenna System (DAS) that is field reconfigurable and support multi-modulation schemes (modulation-independent), multi-carriers, multi-frequency bands and multi-channels. The present disclosure enables a high degree of flexibility to manage, control, enhance, facilitate the usage and performance of a distributed wireless network such as flexible simulcast, automatic traffic load-balancing, network and radio resource optimization, network calibration, autonomous/assisted commissioning, carrier pooling, automatic frequency selection, frequency carrier placement, traffic monitoring, traffic tagging, pilot beacon, etc.

Abstract: An optical amplification device includes: a plurality of semiconductor optical amplifiers to which an optical burst signal is input at a different timing; an optical coupler that combines output signals output from the plurality of semiconductor optical amplifiers; a detection unit that detects an optical inputting to the plurality of semiconductor optical amplifiers; and a control unit that activates one of the semiconductor optical amplifiers where the optical inputting is detected, inactivates the other semiconductor optical amplifier, and remains the activation until another optical inputting is detected in the other semiconductor optical amplifier.

Abstract: An optical processing circuit, such as a combinatorial network, comprises an arrangement of optical logic gates suitable for use in combination with a switched optical node of the kind having at least first and second input ports and two output ports, the node being configurable into either a cross or a bar configuration, and in which the optical processing circuit is arranged so as to receive at least three optical input signals which respectively comprise a packet identifier signal PIH which identifies whether or not a first input signal is present at the first input port of the switched optical node, the first input port being assigned a higher priority than the second input port, a first destination address AH indicating the output port of the switched optical node to which a first information carrying signal, received at the first input port, is intended to be passed, and a second destination address AL indicating the output port of the switched optical node to which a second information carrying signal,

Abstract: A superimposed signal detection circuit detects a signal superimposed on an optical signal in a WDM system. The superimposed signal detection circuit includes: an optical filter having wavelength-dependent loss to filter a plurality of optical signals on which a corresponding superimposed signal is superimposed by frequency modulation; a photo detector to convert the plurality of optical signals filtered by the optical filter into an electric signal; and a detector to obtain information indicated by the superimposed signal respectively superimposed on the plurality of optical signals from the electric signal obtained by the photo detector.

Abstract: Vertical cavity semiconductor optical amplifiers for various photonic devices including all optical logic gate devices and oscillators, where such devices can be implemented to achieve various advantages, including Boolean inversion at high speeds, low power, workable noise margins for cascadability because of input output isolation, and easy of integration in large arrays.

Abstract: An optical logic gate includes: a DNA based nanostructure including DNA and metal nanoparticles coupled to the DNA, the DNA based nanostructure being configured to rotate a polarization plane of an incident light; a polarizer to which light passing through the DNA based nanostructure is incident, the polarizer being configured to extract a component in a direction of a predetermined reference axis from light whose polarization plane is rotated by the DNA based nanostructure; and a detection unit to which light passing through the polarizer is incident, the detection unit being configured to generate a logic signal based on a result obtained by comparing the intensity of the component in the reference axis direction extracted by the polarizer with a predetermined threshold value.

Abstract: The present invention provides optical devices that employ nonlinear optical effects for processing optical signals. For example, such an optical device can include a nano-sized interferometric component that provides an optical output signal via interference of two input signals subsequent to their asymmetric nonlinear phase accumulation. The interferometric element can have a variety of configurations, such as Sagnac, Mach-Zehnder or Michelson configurations.

Abstract: A light intensity subtractor according to one aspect of the present invention includes a light subtraction unit, a feedback circuit, a light input port, a first light output port, and a second light output port. The light subtraction unit receives input light through the light input port, outputs first output light to the first light output port, and outputs second output light to the second light output port. The light subtraction unit generates the first output light by reducing the light intensity of the second output light from the light intensity of the input light in accordance with a control voltage. The feedback circuit is connected to the light subtraction unit through the second light output port, and outputs the control voltage in accordance with the light intensity of the received second output light.

Abstract: A device for use in optical signal control is presented. The device comprises an amplification waveguide, including a pumpable medium, and a reference and a control inputs and an output selectively allowing transmission of light respectively into and out of said amplification waveguide. The reference input, the amplification waveguide and the output define together a transmission scheme for reference light through the pumpable medium. The control input and the amplification waveguide define a depletion scheme for the pumpable medium and control light. The device thus allows for controlling an output signal, formed by the transmission of the reference light, by controllable depletion of the pumpable medium.

Abstract: Systems and methods of performing logical operations with photonic quantum logic gates. The logic gates utilize photon states, usually orthogonal linearly polarized states, to selectively enact self-interference operations whose outputs can be altered by inducing phase shifts in one or more portions of the section of the logic gate where the photon states undergo self-interference. The polarization direction switchings are differentially enacted and/or not enacted, in groupings of switches, to perform various logic operations. Additionally, networked logic gates with interrelated self-interference section phase shifts and output states are described that provide additional capabilities.

Abstract: Provided are an optical switch and an optical logic device. The optical switch includes a plate having a nanometer-sized thickness, a first slit formed in the plate, through which a first light passes, a second slit formed in the plate, separately from the first slit, through which a second light selectively passes, a plurality of first grooves formed on a first side of the first slit, between the first slit and the second slit, and a plurality of second grooves formed on a second side of the first slit, opposite the first side. The first light and the second light may have a phase difference and a focusing of the first light is turned on/off by controlling the second light.

Abstract: A quantum logic gate for qubits, suitable for receiving as inputs at least two polarization-encoded qubits, includes at least one partially polarizing beam splitter (PPBS), the beam splitter comprising a first waveguide and a second waveguide which are constructed in integrated optics, the first and second waveguides having a refractive index contrast of between 0.1% and 6% and a birefringence of between 10?6 and 6*10?5.

Abstract: An optical linear feedback circuit has an optical loop delay path (10) for recirculating a sequence of optical signals, and an output path for outputting delayed optical signals after circulating one or more times around the loop. A selector (50) is provided for selecting one or more of the delayed optical signals from the sequence, and an optical logic circuit (20) is coupled to carry out a logical operation on the selected delayed optical signals to create an optical feedback signal which is coupled to the optical loop delay path, so that the optical feedback signal can be added to the sequence of optical signals already circulating. By recirculating around a loop, each round trip can be regarded as equivalent to a shift of a shift register, so longer sequences can be built up without needing an additional storage cell for each shift function.

Abstract: A combined Brillouin gain and loss process has been created in a polarization maintaining optical fiber to realize all-Optical NAND/NOT/AND/OR logic gates in the frequency domain. A model describing the interaction of a Stokes, anti-Stokes and continuous wave, and two acoustic waves inside a fiber, ranging in length from 350 m-2300 m, was used to theoretically model the gates. Through the optimization of the gain and loss process, switching contrasts of 20-88% have been achieved, under different configurations. Experimental setups for NAND/NOT/AND/OR optical logic gates have been described. A method and system for designing the all-optical logic gates have been also provided.

Abstract: An electromagnetically induced transparent (EIT)-based photonic logic gate. The electromagnetically induced transparent (EIT)-based photonic logic gate is a photonic crystal (PC) and electromagnetically induced transparent (EIT)-based stacked layer which is constituted by a photonic crystal (PCs) layers and an electromagnetically induced transparent material layers. For the photonic crystal (PCs) and electromagnetically induced transparent (EIT)-based stacked layer, a probe field is an input signal which is emitted from the photonic crystal layer and a control field is a control signal which is emitted from the electromagnetically induced transparent material layers. The probe field is an input signal which is emitted from the electromagnetically induced transparent material layers. By varying the detune frequency of probe field and Rabi frequency of control field, the band gap structure can be adjusted.

Abstract: A logic gate comprises a photonic or polaritonic band gap medium and a plurality of nano particles, atoms or artificial atoms are disposed in the band gap medium. Two coupled electromagnetic pulses are propagated within the medium and produce two output pulses. The output pulses are detected or sensed and a third external electronic field controls the relative velocities of the two output pulses. A method for producing a time delay of an electromagnetic pulse is also disclosed.

Abstract: Various embodiments of the present invention are directed to arbitration systems and methods. In one embodiment, an arbitration system comprises a loop-shaped arbitration waveguide (602), a loop-shaped hungry waveguide (603), and a loop-shaped broadcast waveguide (604). The arbitration, hungry, and broadcast waveguides optically coupled to a home node and a number of requesting nodes. The arbitration waveguide transmits tokens injected by the home node. A token extracted by a requesting node grants the node access to a resource for the duration or length of the token. The hungry waveguide transmits light injected by the home node. A requesting node in a hungry state extracts the light from the hungry waveguide. The broadcast waveguide transmits light injected by the home node such that the light indicates to requesting nodes not in the hungry state to stop extracting tokens from the arbitration waveguide.

Abstract: Optical logic gate having a second-harmonic generator element that receives a first and a second optical input signal respectively having a first and a second angular frequency and respectively having a first and a second polarization, and which provides a second-harmonic optical signal having a third angular frequency and a third polarization. The third angular frequency is equal to the sum of the first and the second angular frequency. The third polarization is a function of the first and the second polarization. The second-harmonic generator element includes a second-harmonic generator layer in a material having a non-null second-order optical tensor.

Abstract: Certain embodiments relate to systems and methods providing wires, circuits, or circuit elements comprised of one or more chromophores. The chromophores can be “tuned” to the critical edge between quantum order and quantum chaos providing long coherence times combined with quantum delocalization resulting in coherent transport of excitons. Such tuned chromophore systems provide coherent transport at room temperature.

Abstract: In this invention truth logic is defined as that “Light existence=TRUE” and “NO light or Dark=FALSE”. And through the optical principles (: “Fraunhofer” single slit & “Young” double slits light diffraction pattern), I have designed logical function gates (AND, OR, XOR & NOT), using the optical equipments and a coherent light beam (Laser beam), with no interference of any electronic circuits or devices. This design would lead us to make Optological Gates which run at the light speed, so we would have logical function gates with very high speed.

Abstract: An optical circuit is described which may include an SOA-MZI circuit providing an output signal; and a polarization filtering device (PFD) configured to receive the output signal of the SOA-MZI and to provide at least one signal at the output of the PFD.

Abstract: Data integrity methods are disclosed for quantum computational plasmonic information representation and processing systems. Also disclosed are methods of saving energy in such applications. Also disclosed are methods of monitoring such applications.

Abstract: The present invention provides an EIT-based photonic logic gate, which is constituted by EIT-based stack layers of periodic array of photonic crystal (PCs) layers and EIT (Electromagnetic Induced Transparent) material layers. The input probe signals are incident on the first photonic crystal layer, passing through one or more than one PCs-EIT interfaces and transmitted out from the last EIT material layer. Control filed as the enable signals are incident on each EIT layer to activate the optical logic gate. By varying the detune frequency of probe field and Rabi frequency of control field, its band gap structure can be adjusted. Henceforth, the tunable optical EIT-based photonic logic gate can be achieved as user required.

Abstract: An all-optical spin device is based on spin multistability of trapped microactivity polaritons.

Abstract: There is provided a new architecture for all-optical logic architecture. In this architecture the gate is partitioned into a linear front-end followed by a nonlinear back-end. The logic calculation is practically performed within the linear stage, easing the requirements placed on the non-linear part and thus reducing the gate complexity. The new structures provide flexibility and improved performance for the all-optical logic. The proposed scheme may be integrated optics/electronics. An important additional attribute of our all-optical logic family is reconfigurability, i.e. the ability of the hardware architecture or devices to rapidly alter the functionalities of its components and the interconnection between them as needed.

Abstract: A passive all optical polarization switch and apparatus and methods for implementing logical operations using the switch is provided. The switch converts a first polarized beam having a polarization angle equals to or nearly equals to ±45 degrees into a beam equal to or nearly equal to the vertical component of the first polarized beam. The switch converts a second polarized beam having a polarization angle equals to or nearly equals to ±45 degrees into a beam equal to or nearly equal to the horizontal component of the second polarized beam. The switch combines the vertical component of the first polarized beam and the horizontal component of the second polarized beam to produce an output polarized beam. The switch is used to implement all optical polarization logic gates.

Abstract: 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.

Abstract: A bit-matrix processor including a pair of optoelectronic matrices and a controller for causing the matrices to perform Boolean Matrix transforms to perform logical operations, wherein Boolean logical equivalents include logical AND to replace element-wise multiplication, and logical OR instead of summation. According to one embodiment, the processor includes an optical source matrix for receiving input binary data; a passive optical replicator for replicating a pattern on the optical source matrix and projecting it onto a Spatial Light Modulator (SLM); a database loading device for loading data onto the SLM thereby to perform logical AND with the optical source matrix data; an integrating device for integrating light from the SLM onto a photodiode matrix; and an output signal processing device.

Abstract: Logical operations are implemented using polarization-based logic level representation. An input polarized beam is split into a first beam and a second beam. The first beam is polarized at a first relative polarization angle and the second beam is polarized at a second relative polarization angle. The ratio of the amplitudes of two perpendicular polarization components of the input polarized beam is one or nearly one and the difference between the first relative polarization angle and the second relative polarization angle is 180 degrees or nearly 180 degrees. The relative polarization angle of the input polarized beam equals or nearly equals either the first relative polarization angle or the second relative polarization angle.

Abstract: Electronic logic gates that operate using N logic state levels, where N is greater than 2, and methods of operating such gates. The electronic logic gates operate according to truth tables. At least two input signals each having a logic state that can range over more than two logic states are provided to the logic gates. The logic gates each provide an output signal that can have one of N logic states. Examples of gates described include NAND/NAND gates having two inputs A and B and NAND/NAND gates having three inputs A, B, and C, where A, B and C can take any of four logic states. Systems using such gates are described, and their operation illustrated. Optical logic gates that operate using N logic state levels are also described.

Abstract: 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.

Abstract: 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.

Abstract: An optical linear feedback circuit has an optical loop delay path (10) for recirculating a sequence of optical signals, and an output path for outputting delayed optical signals after circulating one or more times around the loop. A selector (50) is provided for selecting one or more of the delayed optical signals from the sequence, and an optical logic circuit (20) is coupled to carry out a logical operation on the selected delayed optical signals to create an optical feedback signal which is coupled to the optical loop delay path, so that the optical feedback signal can be added to the sequence of optical signals already circulating. By recirculating around a loop, each round trip can be regarded as equivalent to a shift of a shift register, so longer sequences can be built up without needing an additional storage cell for each shift function.

Abstract: Logical operations are implemented using polarization-based logic level representation. An input polarized beam is split into a first beam and a second beam. The first beam is polarized at a first relative polarization angle and the second beam is polarized at a second relative polarization angle. The ratio of the amplitudes of two perpendicular polarization components of the input polarized beam is one or nearly one and the difference between the first relative polarization angle and the second relative polarization angle is 180 degrees or nearly 180 degrees. The relative polarization angle of the input polarized beam equals or nearly equals either the first relative polarization angle or the second relative polarization angle.