120results about "Optical bistable devices" patented technology

An optical semiconductor device has a structure in which a semiconductor active layer is sandwiched by a p-type semiconductor cladding layer and an n-type semiconductor cladding layer and a p-type contact layer is formed on the p-type semiconductor cladding layer side and an n-type contact layer is formed on the n-type semiconductor cladding layer side, wherein two ferromagnetic layers are formed on the n-type contact layer and two ferromagnetic layers are formed on the p-type contact layer. Magnetization directions of a pair of ferromagnetic layers vertically opposed to each other are set to be parallel to each other, and the magnetization directions of adjacent ferromagnetic layers are inverted to each other.

A bistable photonic crystal configuration comprises a waveguide sided coupled to a single-mode cavity. This configuration can generate extremely high contrast between the bistable states in its transmission with low input power. All-optical switching action is also achieved in a nonlinear photonic crystal cross-waveguide geometry, in which the transmission of a signal can be reversibly switched on and off by a control input, or irreversibly switched, depending on the input power level.

A disclosed apparatus comprises a guiding element and a nonlinear element. The guiding element guides optical input signals, at least one of which is phase-modulated, to an interference area where such signals meet and interfere. The resulting interference signal is nonlinearly discriminated by the nonlinear element to produce an optical output signal that can be amplitude- or phase-modulated according to the phase modulation of the input signals. The invention also includes related methods and photonic logic gates.

An optical neural network is constructed based on photonic integrated circuits to perform neuromorphic computing. In the optical neural network, matrix multiplication is implemented using one or moreoptical interference units, which can apply an arbitrary weighting matrix multiplication to an array of input optical signals. Nonlinear activation is realized by an optical nonlinearity unit, which can be based on nonlinear optical effects, such as saturable absorption. These calculations are implemented optically, thereby resulting in high calculation speeds and low power consumption in the optical neural network.

A photonic switch according to the present invention may be formed using one of a selected group of non-linear optical materials. Each of the materials within this group has a refractive index that demonstrates a substantial peak as a function of wavelength, where the peak occurs at a wavelength distinct from the wavelength of the input signal. A method of producing a photonic switch according to the present invention includes fabricating source and drain waveguides using micro-molding or micro-contact printing processes, or MIMIC (micro-molding in capillaries) of a UV-curable polymer. If desired, a gate waveguide may also be formed in part by these processes. The photonic switch also includes a photonic crystal formed from non-linear optical material, which may be formed, for example, using a block copolymer and nanoparticle composite in a MIMIC or μfluidics process. Such a process may employ a functionalized mold material to align the blocks.

A description is given of an optical switching device (1) comprising a transparent substrate (3), a switching film (5) of a hydride compound of a trivalent transition or rare earth metal having a thickness of 300 nm, and a palladium capping layer (7) having a thickness of 30 nm. The capping layer is in contact with hydrogen. An electric current through the switching film (5) can be switched on and off between the terminals (9, 11). Joule heating of the switching film (5) causes a rapid transition from the transparent trihydride state to the absorbing dihydride state. By switching off the current, the switching film (5) cools down, which results in the formation of the absorbing dihydride state. The conversion between both states is reversible and can be repeated many times. The device can be used for controlling light beams, or it can be used in or for a display. Optionally, cooling of the switching film (5) is obtained with a Peltier element in thermal contact with the switching film (5).

An all-optical logic gates comprises a nonlinear element such as an optical resonator configured to receive optical input signals, at least one of which is amplitude-modulated to include data. The nonlinear element is configured in relation to the carrier frequency of the optical input signals to perform a logic operation based on the resonant frequency of the nonlinear element in relation to the carrier frequency. Based on the optical input signals, the nonlinear element generates an optical output signal having a binary logic level. A combining medium can be used to combine the optical input signals for discrimination by the nonlinear element to generate the optical output signal. Various embodiments include all-optical AND, NOT, NAND, NOR, OR, XOR, and XNOR gates and memory latch.

A photonic switch may be formed using one of a selected group of non-linear optical materials. Each of the materials within this group has a refractive index that demonstrates a substantial peak as a function of wavelength. The photonic switch includes a positive gain, and thus acts as a photonic transistor. In addition, a photonic switch is formed so that a gate signal is applied in a direction that is substantially perpendicular to the direction of the input signal so that there is no effective contamination of the input signal by the gate signal affecting the output signal.

A non-volatile programmable electro-optical element alters absorption characteristics of an optical medium that comprises a doped transition metal oxide material including F-centers. The F-centers are electrostatically moved into or out of the regions containing a wavefunction of an optical beam. A specific F-center profile in the transition metal oxide material may be programmed into the optical medium. The F-center profile alters an absorption profile within the optical medium. The spectral range for transmission of electromagnetic radiation in the optical medium may be tailored by the F-centers. Once the absorption profile is set by an electrical signal, the optical element maintains its state even when the electrical signal is turned off. Thus, the programming node may be disconnected from a power supply network, thereby enabling a low power operation of the electro-optical element. The inventive electro-optical element may be employed for both the visible and the infrared wavelength spectrum.

A new reconfigurable cascadable all-optical on-chip device is presented. The gate operates by combining the Vernier effect with a novel effect, the gain-index lever, to help shift the dominant lasing mode from a mode where the laser light is output at one facet to a mode where it is output at the other facet. Since the laser remains above threshold, the speed of the gate for logic operations as well as for reprogramming the function of the gate is primarily limited to the small signal optical modulation speed of the laser, which can be on the order of up to about tens of GHz. The gate can be rapidly and repeatedly reprogrammed to perform any of the basic digital logic operations by using an appropriate analog optical or electrical signal at the gate selection port. Other all-optical functionality includes wavelength conversion, signal duplication, threshold switching, analog to digital conversion, digital to analog conversion, signal routing, and environment sensing. Since each gate can perform different operations, the functionality of such a cascaded circuit grows exponentially.

The invention relates to the field of photon equipment and especially relates to a reconfigurable dynamic full light chaos logic gate which comprises a tunable distribution-feedback laser device, a beam splitter, a vertical chamber surface emission laser device, an optical isolator, a polarization beam splitter, a first subtracter and a second subtracter. The reconfigurable dynamic full light chaos logic gate provided by the invention has the advantages that conversion between a full light chaos logic gate operation and each logic gate operation is achieved; specifically, operations of ''AND'' gate, ''NAND'' gate, ''OR'' gate, ''NOR'' gate, ''XOR'' gate, and ''XNOR'' gate operations as well as mutual conversion can be achieved; and the reconfigurable dynamic full light chaos logic gate can be generalized and applied to logic operations of a full light digital chaos combination.

The invention discloses a unidirectional optical transmitting method for a photonic crystal based all-optical diode. A direct coupling micro cavity and a side coupling micro cavity of the photonic crystal are pumped by two ultra-short pulse laser with adjustable power respectively, wherein the direct coupling micro cavity is taken as a variable transmission unit while the side coupling micro cavity is taken as a variable reflection unit; multiple combinations of optical dual stable states, including a high-energy state and a low-energy state, of the two micro cavities can be realized by choosing proper pulse pumping power based on a nonlinear Kerr effect; and the incident continuous wave signal is subjected to the dual regulation and control by the two micro cavities, so that the forward high transmission or backward high transmission of the all-optical diode can be realized. The invention also discloses a unidirectional optical transmitting apparatus for the photonic crystal based all-optical diode. The pass-through directions of the signal light can be freely controlled by adjusting the pumping power of the ultra-short pulse laser; and extremely high forward transmission and backward transmission contrast ratio and relatively high operating bandwidth can be obtained.

A two-input bistable resonator that can be switched in a robust way by phase modulation of the input beams is presented. An optical flip-flop of the present invention may be embodied as a two-input Kerr resonator. The disclosed switching mechanism is compatible with cross-phase modulation induced by set and reset pulses for realization of an ultrafast, passive, all-optical memory element.

The present invention provides a set-reset flip-flop operating in an all-optical manner. In this invention, a set pulse is inputted from the setting port. In doing so, only oscillation in set mode is generated at the multi-mode interference portion in a waveguide. As a result, a non-inverting output Q is obtained from the non-inverting output port. This state is then continued even if the set pulse input goes off. Next, a reset pulse is inputted to the resetting port. In doing so, at the multi-mode interference portion, oscillation of light in the set mode is halted, and oscillation in the reset mode occurs. As a result, it is possible to obtain an inverting output Q-bar from the inverting output port. This state is then continued even if the reset pulse goes off.

The invention provides an optical bistable device applied to an all-optical switch and an optical memory, which belongs to the technical field of all-optical communication systems. The optical bistable device has a multilayer structure formed by eight first dielectric layers, eight second dielectric layers and fifteen graphene layers, specifically from the upper surface to the lower surface in sequence, a first dielectric layer, a graphene layer, a second dielectric layer, a graphene layer, a first dielectric layer, a graphene layer, a second dielectric layer, a first dielectric layer, a graphene layer, a second dielectric layer, a first dielectric layer, a graphene layer, a second dielectric layer, a graphene layer, a second dielectric layer, a graphene layer, a first dielectric layer, agraphene layer, a second dielectric layer, a graphene layer, a first dielectric layer, a graphene layer, a second dielectric layer, a graphene layer, a first dielectric layer, a graphene layer, a second dielectric layer, a graphene layer and a first dielectric layer. The optical bistable device applied to the all-optical switch and the optical memory has the advantages of reducing the optical bistable threshold.

A method for implementing an electro-optical logic function responsive to first and second logical inputs, includes the following steps: providing, as an output stage, a light-emitting transistor having an electrical input port and an optical output port; and providing, as an input stage, a circuit for receiving the first and second logical inputs and producing a control signal that is coupled with the electrical input port of the output stage.

An optical transistor is disclosed that provides a fast switching time, an amplified gain, and isolation. The optical transistor receives a small optical input signal at an optical base port, generates an amplified replica at an optical emitter port, and generates an inverted replica on a vertical light at an collector port. One embodiment of the optical transistor is implemented with a vertical lasing semiconductor optical amplifiers (VLSOA), wherein the ballast light is used a signal for the collector port.

A high-speed dual-stable optical stark chirp switch device is composed of laser pump source, laser source, semi-transmitting and semi-reflecting polarizer, polarizing planar reflection plate, frequency-doubling crystal, pulse delay unit, pulse delay monitoring controller, medium cavity and receiver. Its advantages are simple structure, and high switching speed.

A flip-flop circuit of the present invention includes a first switch and a second switch which are connected in series to each other. The first switch includes: two input ports upon which light source light and signal light are incident; two output ports for outputting an optical output; and a thermal lens forming element for forming a thermal lens in a predetermined optical inputting condition. Although the second switch is composed in the same manner as that of the first switch, a relation between the wave-lengths to be utilized is inverted. When a state is changed from OFF to ON, a pulse signal is inputted for setting and one of the rays of output light of the second switch is fed-back to the first switch so as to maintain the state of ON. When the state is changed from ON to OFF, a pulse of additional signal light is inputted. Due to the foregoing, the two states of ON and OFF can be stably maintained.

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.