Abstract: A process for creating bipolar and CMOS transistors on a p-type silicon substrate is disclosed. The silicon substrate has typical n+ buried wells and field oxide regions to isolate the individual transistor devices. In accordance with the process, stacks of material are created over the gate elements of the CMOS devices and over the emitter elements of the bipolar transistors. The stacks of material over the gate elements have a silicon dioxide gate layer in contact with the epitaxial layer of the substrate, and the stacks of material over the emitter elements have a polycrystalline silicon layer in contact with the epitaxial layer. Walls of silicon dioxide are created around the stacks in order to insulate the material within the stacks from the material deposited outside of the walls. Polycrystalline silicon in contact with the epitaxial layer is deposited outside the walls surrounding the stacks.

Abstract: A method of fabricating a field-effect transistor is disclosed wherein only two masking steps are used in the development of the device. The semiconductor wafer used in the process has a non-alloyed contact at its top surface, that is, a contact which does not require alloying temperatures in excess of 200 degrees C. The first mask is used to create conventional mesa structures which isolate each individual field-effect transistor from its adjacent neighbors. A second mask is utilized to define the source and drain electrodes and also to create a gap through which the gate electrode structure is fabricated. By using a single mask for creation of both the source and drain electrodes and the gate structure, very close tolerances are obtained between the gate structure and the source and drain regions.

Abstract: A field-effect transistor is created on a GaAs semi-insulating substrate using molecular beam epitaxy by fabricating a delta-doped monolayer with a silicon dopant between two undoped GaAs layers grown over the semi-insulating substrate. A plurality of delta-doped monolayers are grown over the surface of the upper undoped layer interleaved with layers of GaAs having a thickness equal to or less than the tunneling width of electrons in GaAs. A channel is etched through the plurality of delta-doped monolayers to permit a gate electrode to contact the upper undoped GaAs layer. Source and drain electrodes are deposited over the delta-doped monolayers on each side of the channel.

Abstract: A non-alloyed ohmic contact in gallium arsenide is described wherein a plurality of delta-doped monolayers are placed at a predetermined distance from each other and from the metal to semiconductor interface of the contact. The predetermined distance is chosen to keep the tunneling barrier extremely thin. In the embodiment shown, silicon is used as a dopant in the gallium arsenide material but other elements from groups II, IV and VI of the periodic table of elements may be used in other III-V semiconductor substrates.

Abstract: Optical apparatus is disclosed wherein narrow line width light from a source is directed through the substrate of a semiconductor structure and reflected from the gate electrode of a field effect transistor element fabricated on the surface of the semiconductor structure. A quantum well layer serves as the current channel for the field effect transistor, and charge carries from a doped semiconductor layer provide high mobility carriers in the quantum well layer. Changes in the potential between the gate and source electrodes of the field effect transistor causes the normal pinchoff of carriers in the quantum well layer thereby causing changes in the absorption characteristic presented by the quantum well layer.

Abstract: A grating in the upper reflecting layer (103 or 203) of an antiresonant reflecting optical waveguide is used to extract energy of a selected wavelength from the waveguiding layer (102 or 202) into the reflecting layer. In one embodiment the reflecting layer (103) is designed as a gain medium which is pumped in the region of a grating (120) and optically terminated at each end of the device such that the embodiment serves as a laser having a long cavity provided by the waveguiding layer (102) with the gain provided in the short grating region. In a second embodiment the reflecting layer (203) in the region of a grating (211) has an opposite conductivity dopant from that of the waveguiding layer (202) such that the device in this region may be backbiased to serve as a wavelength selective photodetector. By placing two wavelength photodetectors in tandem with gratings (211 and 212)of different pitches a wavelength demultiplexing photodetector is provided.

Abstract: An ion energy filter of the type useful in connection with secondary ion mass spectrometry is disclosed. The filter is composed of a stack of 20 thin metal plates, each plate being insulated from the others and having a centrally located hole with a unique radius. A metallic hemisphere is mounted on a base plate, and the 20 thin metal plates are attached to the base plate such that the plate with the smallest central hole is adjacent to the base plate and the radii of the holes in subsequent plates increase with increasing distance from the base plate. The relative potential of each plate is determined by a series string of 20 resistors with each plate being connected to a different junction in the series string. The radii of the centrally located holes are selected such that the voltage on each plate is inversely proportional to the radius of its centrally located hole.

Abstract: A solid state laser is disclosed wherein a semiconductor active layer is arranged in a Fabry-Perot cavity and the active layer is doped with a rare earth ion having a dominant emission wavelength. The proportion of elements for the compound active layer is chosen such that the bandgap corresponds to a wavelength which is longer than the emission wavelength of the rare earth ion. In the specific embodiment disclosed, the quarternary semiconductor compound is gallium indium arsenide phosphide and the rare earth ion is erbium.

Abstract: An external mirror is positioned relative to the output mirror of a laser to form a Fabry-Perot cavity. The light transmitted by this Fabry-Perot cavity is compared to a reference value in order to develop an error signal which in turn is used to adjust the transmission characteristics of the Fabry-Perot cavity. In the embodiment constructed a beam splitter is positioned to deflect light coupled out of the Fabry-Perot cavity to an optical detector. The output of this detector is compared to a reference voltage in a difference amplifier which generates an electrical error signal. The electrical error signal is coupled to a piezoelectric translator which is attached to the external mirror and is capable of moving that mirror in a way so as to change the transmission characteristics of the Fabry-Perot cavity. Specific embodiments using a dye laser and a soliton laser are also disclosed.

Abstract: Apparatus for measuring the voltage waveform on the metallization lines of an integrated circuit is described. Short high powered pulses of light are coupled from a laser and focused on the metallization line of the integrated circuit which is coupled to receive a voltage waveform that is synchronized to the output laser pulses. Electrons are emitted from the metallization line due to the multiphoton photoelectronic effect induced by the pulses of light. An electron energy analyzer having a uniform extraction grid as its most remote element is positioned with the extraction grid as close as possible to the integrated circuit and the laser pulses are focused through one of the holes of this uniform grid. An output circuit is connected in a feedback arrangement which receives the output pulses of the energy analyzer and develops a voltage on a second uniform grid called the retarding grid that is positioned a predetermined distance from the extraction grid inside the electron energy analyzer.

Abstract: A planar silicon dioxide waveguide with low loss for the TE mode has been built on a silicon wafer by separating the waveguide from the substrate with a relatively thin layer of polycrystalline silicon and a layer of silicon dioxide having a combined thickness less than that of the waveguide. The separating layers provide a high antiresonant reflectivity which is operative over a broad range of wavelengths.

Abstract: Devices are optically interconnected on a large scale integrated circuit by fabricating gratings on optical sources that direct the light beams toward a reflecting surface. The reflecting surface is positioned a predetermined distance from the surface of the chip such that it reflects light beams from the sources toward detectors that are fabricated on or near the surface of the chip.

Abstract: The invention relates to a hand-held device for detecting whether or not an optical fiber is carrying a light signal. The device includes a spring loaded hook for grabbing an exposed optical fiber anywhere along its length, thereby introducing microbending, a photodetector for responding to the presence of light emitted in the proximity of the microbend, and a light emitting diode connected by way of an amplifier to the photodetector for indicating when a light signal has been detected. Upon release of the spring loaded hook, the fiber returns to its normal state. The device can be easily modified to indicate not only the presence of a light signal, but also the strength of the signal and the direction in which the signal is being transmitted.

Abstract: A portion of the pulsed output of a 3-mirror, folded, astigmatically compensated cavity of a c.w., mode-locked, color center laser is coupled into a single-mode, polarization-preserving optical fiber. Following compression of the pulses by their propagation through the fiber, the shortened pulses, which take the form of essentially solitons, are fed back into the laser cavity so as to coincide and be in phase with the pulses in the laser cavity. Through the process of stimulated emission in the color center crystal, the injected pulses force the laser itself to produce shorter pulses of essentially the same shape as the solitons. Also described are embodiments employing a mode-locked semiconductor, fiber-Raman laser, and unidirectional pulse propagation in the fiber. Two of the fiber-Raman laser embodiments have separate gain and pulse shaping sections of optical fiber joined by an optical fiber directional coupler.

Abstract: A store and forward facility for use in a multiprocessing, multinode environment is disclosed wherein two fundamental processes (transfer and delivery) perform the bulk of the activities required in this facility. A transfer process permits the creation of a message by an originating applications process and transfers this message to a similar transfer process in each of the nodes to which the message is to be delivered. This message is then in turn transferred to a delivery process which maintains a work item for each message to be delivered to a destination applications process and causes a notification to be sent to that destination application process when an earliest delivery time specified in the message has been reached. The delivery process causes the destination applications process to be created if that process is not currently executing.

Abstract: A nonlinear optical device includes a layered semiconductor structure having layers of different energy band gap materials. Alternate layers of the structure are arranged for containing trapped charge. An input light beam is applied to the layers. A control light beam varies the trapped charge for controlling propagation of the input light beam through the structure.

Abstract: A dual-clock, edge triggered, flip-flop circuit wherein one set of outputs responds to two independent inputs without giving rise to indeterminate states regardless of the combination of inputs comprising a first pair of gates (1-2 or 11-12) cross-coupled to form a first trigger flip-flop. A second pair of gates (7-8 or 17-18) are cross-coupled to form a second trigger flip-flop. A third pair of gates (4-5 or 14-15) are cross-coupled to form an output flip-flop having set and reset terminals and a pair of output terminals. A gate (3 or 13) is coupled from the output of the first trigger flip-flop to the set terminal of the output flip-flop, the input to the first trigger flip-flop also being coupled to the input of this latter gate. Another gate (6 or 16) is coupled from the output of the second trigger flip-flop to the reset terminal of the output flip-flop, the input to the second trigger flip-flop also being coupled to the input of this gate.

Abstract: A digital latching circuit includes a quantizer having an input pair of emitter-coupled transistors connected with output transimpedance circuits. The quantizer is responsive to the state of an input signal applied to the input pair for producing from the output transimpedance circuits a quantized output signal. A feedback pair of emitter-coupled transistors is interposed between the outputs of the transimpedance circuits and the inputs to the transimpedance circuits. Current pulses are applied alternatively to the common emitter circuits of the input pair and the feedback pair of transistors for alternatively enabling the quantizing of the state of the input signal and the latching of that quantized state.

Abstract: A decision circuit is responsive to digital input signals and to timing signals for reshaping and retiming the input signals into reshaped and retimed output signals. The decision circuit also is responsive to the digital input signals and absence of the timing signals for reshaping but not retiming the digital input signals into reshaped output signals which are transmitted. Thus the circuit produces and transmits reshaped output signals even upon failure to apply the timing signals required by a prior art decision circuit.

Abstract: Several types of nonlinear characteristics are provided in an optical device wherein at least two optical materials are constructed to provide a waveguide structure. At least one of the materials has a dominant nonlinear characteristic over the length of the waveguide that is commonly referred to as the Kerr effect. The index of refraction in this material is a function of the light intensity in the waveguide. By selecting materials that provide either positive or negative Kerr coefficients, and by constructing the device with the nonlinear material either as the core or as the cladding layer, power output versus input characteristics that exhibit both limiting and amplification can be provided. A bistable characteristic is provided in one of the embodiments by terminating the waveguide structure with a mirror. Specific embodiments using carbon disulfide and polydiacetylene as the nonlinear materials are disclosed.