Abstract: A thermostat includes a case, including an exterior, that is made of conductive material. A cover plate is made of a conductive material. The cover plate is connected to the case to define a sealed interior. The cover plate has a contact projecting into the sealed interior. The contact is fixed with respect to the case and has an interior contact position. An insulator sheet is disposed between the case and the cover plate. A blade is disposed in the sealed interior. A second end of the blade moves between a first position where it abuts the contact position of the contact and a second position where it is spaced from the interior contact position of the contact. A resistor is mounted on a first end of the blade. The resistor is disposed between the cover plate and the blade in the sealed interior of the case. The resistor has a first side facing and abutting the cover plate, and a second side facing and abutting the blade so that the resistor is electrically connected between the cover plate and the blade.

Abstract: An optoelectronic cell structure includes a plurality of pnpn-devices and circuitry for driving these pnpn-devices. The anodes or the cathodes of said pnpn-devices tied together form a competition node allowing differential charge amplification to take place. The unconnected electrode of each of the pnpn-devices is driven by a pair of complementary transistors. Light input on the pnpn-devices is converted into charge carriers. A forward bias amplifies the difference in charge content in the pnpn-devices by differential competition. A reverse bias turns off each pnpn-device at its own pace, the turn-off times rendering an estimate of the charge content in each pnpn-device present before turn-off. The total system forms a sensitive optical receiver for use in optical interconnects between two or more locations.

Abstract: Disclosed is a nonbiased bistable optical device and a method for fabricating the device, which has a semi-insulating GaAs substrate; a lower mirror having a plurality of reflecting layers which are repeatedly formed on said substrate at least more than twelve times, each of said reflecting layers having a first reflecting film having a first refractive index on said substrate and a second reflecting film a second refractive index different from the first refractive index; a first contact layer formed on the lower mirror; a first buffer layer formed on the first contact layer; a multiple quantum well(MQW) having a plurality of shallow layers which are repeatedly formed, each of said shallow layers having a barrier and a shallow quantum well; a second buffer layer grown on said MQW; and a second contact layer formed on said second buffer layer. The device has an excellent bistablity even without an external applied voltage.

Abstract: A semiconductor optoelectronic device which can be used to perform the logical INVERTER or NOR operation. The device includes a surface-emitting laser 200 electrically coupled to a heterojunction phototransistor 240. When the total illumination intensity at the phototransistor is below a given threshold, the laser is in a lasing state; when the total illumination exceeds the threshold, the laser is in a non-lasing state. The phototransistor is operated at bias voltages below the threshold for avalanche effects.

Abstract: An optical gate array includes a photodetector, an optical modulator, and a reflecting structure arranged therebetween. The photodetector, the optical modulator, and the reflecting structure are composed of semiconductor materials. The photodetector includes an MQW (Multi Quantum Well). The reflecting structure is constituted by a distributed Bragg reflector formed by alternately stacking semiconductor layers having different refractivities. The photodetector and the optical modulator are arranged to receive light from different directions. The modulation characteristics of the optical modulator are controlled by the intensity of light radiated on the photodetector. The reflecting structure connects the photodetector and the modulator electrically and isolates lights radiated on both parts. A plurality of optical gates, each constituted by the photodetector, the optical modulator, and the reflection structure, are two-dimensionally arranged.

Abstract: This invention describes a dual mode optical switching device comprising organic quantum well regions interfacing with inorganic semiconductors. Each mode generates excitons and a photocurrent in their respective quantum well regions in response to incident control beams of different wavelengths of light. The photocurrents in each mode independently modulate the transmission of the lower frequency signal beams. Multiple hybrid organic/inorganic quantum well optical devices can be crafted into optical logic gates by using light impulses in a manner that is analogous to the way electronic gates are used in electronic systems. These devices can also perform as optical switches and optical interconnects between electronic elements. Thus the processing units are electronic and the connections between them are optical, comprising an opeoelectric system with higher data throughput that will exceed electronic systems.

Abstract: Enhanced optical information processing capability is achieved by providing a self-electrooptic effect device (SEED) which modulates one or more power supply beams to provide integer gain in an input optical signal. This "integer gain" SEED includes a predetermined number of quantum well diodes electrically connected in series with a current supply so that, at steady state, each quantum well diode conducts the same current and thus absorbs the same amount of optical power. An optical input signal is replicated by configuring the quantum well diodes such that each quantum well diode receives its own power supply beam. The optical input signal is amplified by configuring the quantum well diodes such that a single power supply beam passes through all of the quantum well diodes.

Abstract: Optical analog information processing capability is achieved by providing a SEED device configured to operate in a differential mode. This "differential SEED" utilizes pairs of input signal beams to represent bipolar analog data and to process those data in a linear fashion. The difference in the optical powers of the input signal beams is used to modulate the absorption of power supply beams in quantum well diodes, such that the difference in the absorbed powers in the quantum well diodes is proportional to the difference in the powers of the input signal beams. The differential SEED can be configured to perform various image processing operations on bipolar analog data, including, for example, image addition and subtraction, optical multiplication, and evaluating spatial derivatives.

Abstract: An optical binary data processor which utilizes a plurality of light beams (or other waves, such as sound waves) which diffract at two or more apertures and which interfere such that the resulting pattern of illumination may be read to yield a particular logic operation. The optical data processor is capable of performing conventional binary logic operations on anywhere from two to N optical inputs, and multiple processors may be cascaded to perform any level of combinational logic.

Abstract: Monolithic optically bistable modulator arrays, such as an M.times.N array of S-SEEDs, are electrically addressed with a matrix of electrical row and column contacts. Connected to the center node of each S-SEED is an addressing means having elements, such as diodes, transistors, or capacitors, which are electrically enabled and disabled.

Abstract: Disclosed are articles and systems that comprise optically communicating logic elements. Exemplarily, a first logic element is a real space transfer logic element having two or more electrical input channels and an optical output channel, and a second logic element has two or more electrical input channels and an optical or an electrical output channel. Associated with at least one of the electrical input channels of the second element are means ("switching means") whose electrical state is responsive to an optical signal that impinges on the switching means (e.g., a photoconductor, phototransistor or photodiode). The elements are arranged such that the output signal of the first element impinges on the switching means, whereby the output of the second element is responsive to the output of the first element. In an exemplary embodiment the inventive article comprises massively parallel signal processing means comprising a multiplicity of optically communicating levels.

Abstract: An optical amplifier having a saturable absorption region is operated below the lasing threshold for the device. Non-linear effects and bistability are observable at temperatures above room temperature. A selected input wavelength .lambda..sub.i within the gain spectrum of the device is amplified and an output at the same wavelength .lambda..sub.i is produced. This is in contrast to the normal operation at threshold, where there is a wavelength shift to the lasing wavelength and, depending on the laser used for the naturable absorption device, the output may be multimode for a monomode input. Best gain is achieved by tuning the input wavelength to a peak of a Fabry-Perot mode in the gain spectrum for the amplifier.The amplifier may be used as wavelength controlled optical switch, when operated bistably, or as a regenerative amplifier when operated in the non-linear region without hysteresis effects.

Abstract: Disclosed is an apparatus utilizing a light emitting semiconductor device which has a pumped region and an unpumped absorber region and in which an active layer has a quantum well structure.In this light emitting semiconductor device, driving current/light output characteristics have dependence on the pulse width of a driving current. A logic unit or a noise reducing apparatus is realized utilizing this property.Furthermore, in the above described light emitting semiconductor device, the central wavelength of emitted light has dependence on a driving current or dependence on driving time. A light beam scanner can be realized utilizing this property.

Abstract: An optoelectronic memory, logic, and interconnection device having an optical bistable circuit as an essential element. The optical bistable circuit includes an optical bistable switch which is a light emitting device and a first phototransistor detecting the light emitted from the light emitting device, connected in series, a second phototransistor connected in parallel to the optical bistable switch which does not detect the light emitted from the light emitting device, and a load resistor connected in series to the optical bistable switch. The optoelectronic memory, logic, and interconnection device operates as an optoelectronic memory device turned on and off with the same light source, as an optoelectronic logic device executing exclusive OR operation, or as a light source for reconfigurable optical interconnection.

Abstract: An optoelectronic apparatus where information is communicated to and from the apparatus in the optical domain, but where the apparatus includes a transmission gate advantageously interposed between successive optoelectronic gates to sequentially convey information internally in the form of electrical, rather than optical, signals. Illustratively, the transmission gate is optoelectronic and comprises two back to back p-i-n photodiodes each including a quantum well region. The first and second optoelectronic gates are S-SEEDs comprising p-i-n photodiodes also each including a quantum well region. The transmission gate is responsive to a first level of the optical control signal for substantially blocking current, and to a second level of the optical control signal for substantially passing current. Applications of the apparatus include its use in a shift register, 2.times.1 switch, 1.times.2 switch, and an exclusive OR gate.

Abstract: A laser diode and an optical switching device are connected in parallel relative to a power supply. The optical switching device is turned on by receiving an input light, and stores the ON state, so that the laser device is turned off. As a result, an electric power consumption is decreased, the structure is simplified, and the adjustment becomes easy.

Abstract: A plurality of ultra-high speed light receiving elements are provided each of which has two rectifier junctions being connected to each other opposite in polarity and has a substantially symmetrical electrode arrangement. A bias voltage is applied to each of the light receiving elements from one or a plurality of power sources. Electrical signals produced by the light receiving elements in response to input optical pulse signals are superposed on one another to produce one or a plurality of output electrical signals representing a predetermined logic operation with respect to the input optical pulse signals. Depending on the arrangement of its elements, the optical logic operation system functions as an OR circuit, AND circuit, NOT circuit, EXCLUSIVE OR circuit, or half-adder circuit.

Abstract: A pulse converter includes a set-reset flip/flop, or OPTOGLE 10, having a pair of cross-coupled switching devices such as transistors Q1, Q2 or logic gates G1, G2. The circuit operates by coupling pulses of optical radiation to each of the devices for causing the devices to alternately toggle between an on-state and an off-state. Optical inputting devices such as photodiodes or photoconductors, or the gates of FET transistors themselves, are integrally formed upon a common substrate with the switching devices for minimizing stray inductive and capacitive reactances to substantially eliminate temporal jitter in an electrical output signal. A pulsed laser source and a fiber optic or optical waveguide provide non-overlapping optical pulses to each of the switching devices.

Abstract: The invention comprises a semiconductor substrate with a plurality of photoconductive elements. The photoconductive elements are connected to form a combinational logic ripple carry adder having only AND and OR logic gates. An optic substrate overlies the semiconductor substrate and directs light representing logic parameters onto the logic gates. The ripple carry adder has complementary inputs and complementary outputs to enable the use of only AND and OR gates.

Abstract: The invention comprises a semiconductor substrate with a plurality of photoconductive elements. The photoconductive elements are connected to form combinational logic gates. An optic substrate overlies the semiconductor substrate and directs light representing logic parameters onto the logic gates. The combinational logic gates have complementary inputs and complementary outputs such that combinational logic can be carried out using only AND and OR gates.

Abstract: Boolean logic functions are provided in a programmable optical logic device by combining a symmetric self-electrooptic effect device (S-SEED) with a logic control element for optically programming the S-SEED to initiate logic operations from a predetermined state. The predetermined preset state together with subsequent application of optical data signals to the S-SEED permit the desired logic operation to be performed on the optical data signal by the optical logic device. Logic operations which may be programmed into the optical logic device include AND, NAND, OR and NOR functions. A complementary pair (Q and Q) of optical signals is provided as output from each optical logic device.

Abstract: Apparatus having a plurality of photodetectors interconnected to form an electrical circuit corresponding to any given logic function comprising at least two of the four basic AND, OR, NAND, and NOR logic operations. The apparatus performs optical logic without optical cascading since the electrical circuit controls the generation of an optical output beam based on the value that the given logic function assumes in response to a plurality of optical signal beams each incident on at least one of the photodetectors. A complementary optical output is obtained and time-sequential operation is effected when two, serially connected quantum well p-i-n diodes comprising an S-SEED are used to generate optical output beams in response to the voltage developed by the electrical circuit of interconnected photodetectors.

Abstract: Apparatus having a first electrical circuit, comprising a plurality of photodetectors interconnected such that the first circuit corresponds to any given logic function, is connected in series with a second circuit comprising a plurality of photodetectors interconnected as the conduction complement of the connections of the first circuit. The apparatus performs optical logic without optical cascading since the first and second circuits control the generation of an optical output beam based on the value that the given logic function assumes in response to a plurality of optical signal beams incident on the photodetectors of the first circuit and a plurality of complementary beams incident on the photodetectors of the second circuit. A complementary optical output is obtained and time-sequential operation is effected when two, serially connected quantum well pin diodes comprising an S-SEED are used to generate optical output beams in response to the voltage developed by the first circuit.

Abstract: Apparatus comprising a monolithic structure having an array of substructures, e.g., mesas, each including first and second photodetectors electrically connected as components of different self electro-optic effect devices. The devices are optically interconnected due to the positioning of the component photodetectors within a single mesa.

Abstract: An opto-electronic XOR gate includes a pair of diode type light sources connected back to back in parallel by a pair of input leads to which first and second electronic logic signals are applied. With only one logic signal in the high state, one of the diode-type light sources is forward biased while the other is reverse biased. With both logic signals high or low neither diode-type light source emits. A two to one fiber optic combiner (FOC) provides a single optical output which is on only when only one electrical signal is high. If an electronic output is desired, a single photodetector converts the output of the FOC to an electronic logic signal. For performing the exclusive OR operation on optical input signals, a pair of photodetectors and buffer amplifiers and connected to the input leads. For 10 to 12 GHz switching speeds laser diodes are used as the diode-type light sources. When lower switching speeds are satisfactory, light emitting diodes can be used as the diode-type light sources.

Abstract: An optically bistable device, such as a symmetric self electro-optic effect device (S-SEED), is forced into a metastable state prior to the incidence of an optical input signal thereto, thereby increasing the sensitivity of the optically bistable device to the optical input signal, reducing both the switching time and the optical input signal energy required to switch the device. The metastable state is entered into by one of three techniques: (1) turning off the bias voltage V.sub.0 of the device with optical bias beams on then turning on the bias voltage V.sub.0 with the optical bias beams off; (2) applying a predetermined voltage to a node in the device, the predetermined voltage being substantially the metastable state voltage or V.sub.0 /2; or (3) subjecting the device to equal intensity optical bias beams having a wavelength longer than the exciton wavelength.

Abstract: Lower switching energies, enhanced electroabsorption and reduced tolerances on the operating wavelength of incident light are achieved while contrast between low and high absorption states is maintained in accordance with the principles of the invention by a self electrooptic device including an intrinsic quantum well region having an asymmetric electronic characteristic across a narrow bandgap subregion between the two wide bandgap layers defining the quantum well region. As a result, the quantum well region polarizes electrons and holes within the subregion in an opposite direction relative to a direction for an electric field applied to the device. The asymmetric electronic characteristic is realized as a compositionally graded, narrow bandgap layer or as a pair of coupled narrow bandgap layers of differing thicknesses separated by a thin wide bandgap layer.

Abstract: A light induced unidirectional light switch is described wherein a unidirectionally emitting medium is obtained using the method of Doppler compensation by light-induced velocity-dependent light shifts. The emission in the emitting medium can be switched on by a pulse of laser light which acts as a light induced light switch.

Abstract: An optically bistable device 100 is disclosed having first and second semiconductor multiple quantum well regions 101 and 102 with complementary high and low absorption levels for emitting first and second output light beams 162 and 163 having complementary low and high power levels. The optical device comprises first and second photodetectors 103 and 104 having respective quantum well regions 101 and 102. The photodetectors are responsive to first and second light beams 160 and 161 for electrically controlling the optical absorption of each of the two quantum well regions. The state of the device is determined by the transmission level of light beam 161 passing through multiple quantum well region 102 and being emitted as output light beam 162, whereas the complementary state of the device is determined by the transmission level of complementary output light beam 162.

Abstract: An optically bistable device 100 is disclosed having a self electro-optic effect device (SEED) 104 and a variable optical attenuator 103 for maintaining the state of the SEED over a wide power range of two input light beams. The SEED is responsive to the relative power levels of the two input light beams for assuming one of two states. The state of the SEED is determined by the transmission level of one of the beams passing through quantum well region 102 of the device. The variable optical attenuator concomitantly varies the power level of the two input beams to maintain the present state of the SEED over a wide range of input light beam powers. When operated in a bistable operating region of the device, a control light beam with a low power level changes the device from one state to another. Two threshold values of a ratio of power between the two input beams establish where the device switches from one state to the other.

Abstract: The invention is a nonlinear or bistable optical device having a low switching energy. The invention uses a means responsive to light for generating a photocurrent, a structure having a semiconductor quantum well region, and means responsive to the photocurrent for electrically controlling an optical absorption of the semiconductor quantum well region. The optical absorption of the semiconductor quantum well region varies in response to variations in the photocurrent. A photodiode or phototransistor may be used as the means responsive to light, and may be made integral with the structure having the semiconductor quantum well region. An array of devices may be fabricated on a single chip for parallel logic processing.

Abstract: The invention is a nonlinear or bistable optical device having a low switching energy. The invention uses a means responsive to light for generating a photocurrent, a structure having a semiconductor quantum well region, and means responsive to the photocurrent for electrically controlling an optical absorption of the semiconductor quantum well region. The optical absorption of the semiconductor quantum well region varies in response to variations in the photocurrent. A photodiode or phototransistor may be used as the means responsive to light, and may be made integral with the structure having the semiconductor quantum well region. An array of devices may be fabricated on a single chip for parallel logic processing.