Showing papers on "Optical switch published in 1976"

Switched directional couplers with alternating ΔΒ

Abstract: Coupled waveguide structures with sections of alternating phase mismatch are proposed as switched directional coupler configurations in which complete conversion of light from one guide to the other can be achieved by an electrical adjustment. These structures can be used to make electrooptic switches and amplitude modulators in integrated optics form with improved conversion and on-off ratios. Couplers with 2, 3, 4, and N sections of alternating phase mismatch are analyzed, and diagrams describing their switching characteristics are given.

A kilovolt picosecond optoelectronic switch and Pockel's cell

Abstract: Photoconductivity produced by picosecond optical pulses in silicon has been used to switch electrical signals as large as 15 kV The signals have been used to drive a traveling‐wave Pockel’s cell for efficient optical switching with a measured rise time of approximately 25 psec

Experimental 4×4 optical switching network

Abstract: An optical waveguide 4×4 switching network fabricated by integrating five switched directional couplers with stepped ?s reversal on a single LiNbO3 substrate is reported. The maximum crosstalk observed on any output waveguide was down by 18 dB.

Performance limitations imposed on optical waveguide switches and modulators by polarization

Abstract: Crosstalk in optical waveguide switches/modulators caused by having two polarizations simultaneously present is studied in this work. This situation is expected to arise when fiber optical transmission lines are coupled to integrated optical circuits. Modulator/switch performance is found to be strongly affected by having two propagating polarizations. Conditions on device design are found that minimize the polarization sensitivity of switches/modulators, making them suitable for use with fiber optic transmission lines.

Silicon p−n insulator-metal (p-n-I-M) devices

Abstract: Silicon p-n-I-M devices with thin insulating layers ( thicknesses ⩽ 30 A ), named MTIS devices, have been developed. The two terminal device shows an S-shaped negative resistance characteristics similar to a Schockley diode (or p-n-p-n diode). Typically the threshold and sustaining voltages are 10 ∼ 15 and 1.3 ∼ 2 volts, respectively. The former however can be controlled by optical illumination. Turn-on time including delay is less than 2 nsec and turn-off time − 1 nsec or less. A thyristor-like device with its third terminal connected to the n-layer shows switching operation controllable by this terminal. A monolithic linear array of p-n-I-M diodes with 30 μm spacing operates as a shift register through coupling of adjacent diodes. Life of the two terminal devices recorded at present is over 1.5 × 104 hr. These devices can be applied to low power and high-speed electrical switching and also to optical switching and integrated logic circuits.

Optical transistors and logic circuits embodying the same

Abstract: An optical transistor wherein an optical medium receives a pump signal and produces therefrom an internal optical signal, an optical control signal being directed into the optical medium to perturb the optical properties of the medium and to thereby modify the amplitude of the internal optical signal. A plurality of optical transistors are shown in various logic configurations.

Electro-optic Y-junction modulator/switch

Abstract: A new type of electro-optic channel-waveguide modulator/switch for integrated optics has been proposed and demonstrated in which the transverse confinement of The guided optical wave in a channel waveguide is controlled and the optical energy is selectively fed to either Y-junction output port by control of the applied electric field. The device exhibited 75% modulation depth for an applied voltage swing of 6 V peak to peak and a potential bandwidth of 10 GHz.

Mechanical optical-fibre switch

Abstract: An optical-fibre switch is described which depends on transverse mechanical motion of found fibres within a square-bore tube. The theoretical loss of the switch, when closed, can be as low as 0.05 dB and many tens of decibels when open.

Fiber optic control modules and system employing the same

Abstract: Disclosed are control modules for use in systems utilizing flexible, optical fiber bundles, which control modules include an optical switch and an optical receiver. Each is provided with quick-disconnect fittings for receipt of optical fiber bundles. Also disclosed is a control system for an apparatus including a machine having mechanical parts which perform a series of operations wherein the control inputs to the machine are generated by the control modules operated in response to mechanical movements of the machine.

A phased, optical, coupler-pair switch

Abstract: We analyze an optical switch consisting of two directional couplers with an intermediate phase-compensating network. The conditional requirements on coupler length, phase mismatch between guides in each coupler, and phase compensation between couplers are established such that two switching states exist. It is shown that, to switch between states, (i) The couplers must be 3 dB or stronger. (ii) Each coupler must be “adjusted” to become a hybrid by controlling the phase mismatch between guides. (iii) The differential phase φ must be initially set to turn on one state. (iv) An additional increment of π in the phase shift causes switching to the second state. It is estimated that the controlling voltage required to activate the bipolar switch is of the order of 1 to 2 V for a 3-µm guide with 3-mm-long electrodes in Ti-diffused LiNbO 3 . We are currently in the process of fabricating such devices.

Low crosstalk optical switch

Abstract: A low crosstalk optical switching matrix of individual optical switches wherein anyone of n input ports may be addressed to any one of n output ports. Ports of the individual optical switches which are employed for inter-row and inter-column coupling at the interior of the matrix are not used in the last row and column and are terminated with optical signal absorbers thereat, thus providing a means for absorbing non-addressed signals and spurious reflections. The crosstalk properties of the matrix are further improved by utilizing a multiplicity of four port switching elements in tandem for each individual optical switch.

Optical-fiber impulse-response measurement system

Abstract: This paper describes time-domain instrumentation that was designed to measure impulse response and delay of multimode optical fibers that are being used in an experimental optical communications system at Bell Laboratories. Time-domain data is transformed to frequency-domain by a minicomputer, and the result is displayed as the fiber's baseband frequency response.

Light modulation matrix for image reproduction - with magnetooptical matrix which produces switching control of cells based upon Faraday effect

Abstract: The modulation matrix is for an image display or projection system and uses a structured magneto-optical layer e.g. iron-garmet to provide electrical rather than optical switching. For a direct transmission system light is transmitted over a polariser (P) through the modulation matrix (M) with associated switching cells (2) over a coupling plate (K) onto the analyser (A). The modulation matrix consists of an iron-garnet layer on a substrate with resistive layer sandwiched between two electrodes mounted on top. For the transmitting version the electrodes and the resistive layer are transparent. Up to 250,000 magneto-optical cells may be produced that are selectively switched by current pulses to produce heat generation.

Thin film optical switching device

Abstract: A thin-film optical switching device has a substrate of fused quartz, an optical slab waveguide or Corning glass No. 7059, a thin film crossing a portion of the length of the waveguide, and an interdigital transducer on the substrate for generating an elastic surface wave to propagate it through the thin film. The optical waveguide, and thin film have respective parameters such that almost all energy of an optically guided wave and the elastic surface wave are concentrated into the thin film while the optically guided wave within the thin film undergoes acousto-optical interaction, that is, Bragg diffraction.

Multiple-channel data switch

Abstract: A data switch which can rapidly configure and reconfigure multiple channels between computer equipments for digital data transmitted at a rate in excess of 10 megabits per second. The switch includes a switch matrix connected between an input and an output voltage level buffer, a mini computer, and control circuitry. The switch matrix comprises three stages, each containing 256 switching elements which are active integrated circuit elements each having 16 data inputs and one data output. A channel is configured through the switch matrix when one switching element in each stage responds to a control signal to couple one of its data inputs to its data output, over a million different channel configurations being possible. Each switching element is heavily grounded to effectively eliminate cross talk between channels and each data input line of each switching element is provided with an amplifier to improve time fidelity of the switch.

Resettable overcurrent-protected direct current power supply

Abstract: A bistable magnetic switch circuit includes one terminal coupled to a source of direct current voltage, a contact coupled to the other terminal of the bistable switch circuit and an armature controlled by the bistable switch circuit to make and break contact with the contact, the bistable switch circuit being energized at a given trip-rated current. A transistor has its collector coupled to the other terminal of the bistable switch circuit, its emitter coupled to a utilizing load and its base coupled to the armature remote from the contact, the transistor being rendered non-conductive when the bistable switch circuit is energized to provide the desired overcurrent protection. A reset switch is coupled between the other terminal of the bistable switch circuit and ground potential to reset the bistable switch to prepare the bistable switch circuit to protect against a continuing or a new overcurrent condition.

Optical PCM group transmission repeating system

Abstract: An optical fiber communication system using group transmission which transmits PCM information by utilizing an optical fiber group composed of a plurality of optical fibers. The PCM information in a plurality of optical fibers is stored in a memory of the system's sending terminal, the stored information of each memory is read out by simultaneous clock pulses so as to send out the information to a transmission line which is composed of a plurality of said optical fibers. A repeater is provided in the transmission line having at least one of the following circuits, an AGC circuit, a light element control circuit, a power supply circuit and a supervisory circuit. The supervisory circuit is commonly provided for checking a plurality of signals which is transmitted by the above-mentioned optical fibers. In the repeater, the signals are regenerated by simultaneous clock pulses which are generated from one common timing circuit, and the phases of the signals are arranged in order for sending out said signals to the transmission line composed of said optical fibers.

Integrated optical circuits for telecommunications

Abstract: Optical signals can be guided and manipulated in thin films deposited on a substrate. The new technology will allow the implementation of key circuit functions at optical frequencies.

Radiant energy integrating meter

Abstract: A radiant energy integrating meter having one or more parallel connected reversed biased radiant energy sensor cells connected to an integrating circuit having an integrating capacitor. A trigger circuit having a differential amplifier, connected to the integrating capacitor, which drives a further amplifier, is adapted to close a first switch such as a silicon controlled rectifier in response to a predetermined integrated sensor current. A counter circuit is coupled to the first switch and advances by one each time the first switch is closed. A second switch such as a relay is coupled to the first switch to provide a discharge path for the integrating capacitor. Finally, a delay circuit is coupled across the first switch to open the first switch after a predetermined time delay.

Electric safety switch circuitry

Abstract: In an electric safety switch circuit for use in apparatus having at least one safety switch for detecting at least one abnormal condition of the apparatus, switching elements are connected between a power source and the apparatus. The voltage of the main power source is transformed to a lower voltage and the switching elements are opened or closed by control circuitry in the low voltage circuit. The at least one safety switch is connected to the voltage transformer and the control circuitry such that the actuation of the at least one safety switch upon detection thereof of an abnormal condition actuates the control circuitry to open the switching elements and disconnect the apparatus from the power source. In one embodiment a primary switch is interconnected between the power source and the electric safety switch circuit, and in a modified embodiment the primary switch is connected in the electric safety switch circuit itself. The reduction in the voltage and current in which the primary switch and/or the at least one safety switch are interconnected results in improved reliability, durability, and operating life of the electric circuit as well as providing commensurate decreases in the cost of the electric circuit.

Circuit arrangement for electronically applying an alternating voltage

Abstract: The disclosure relates to an integrated circuit which is suitable as an LF switch, which enables switching without the switching clicks normally produced by semiconductor circuits. For this purpose the circuit arrangement is designed so that during switching the input direct voltage of the switch remains substantially unchanged.

Infrared polarization rotator and optical switch

Abstract: An optical polarization rotator is developed for use with infrared radiation using a nonlinear, two-photon interaction in a solid medium. The mechanism employed is resonance dispersion, where the sum frequency of an infrared beam to be rotated and a visible control beam is close to the frequency of a two-photon transition of exciton states, thereby producing different amounts of dispersion for the two orthogonal components of the linearly polarized infrared beam. The result of a phase difference between the two components is a rotation of the plane of polarization of the infrared beam.

Optical control device for integrated optical circuit

Abstract: An optical control device suitable for utilization in an integrated optical system The control device employs a monocrystalline substrate and a thin monocrystalline layer mounted thereon

The Integrated Power Switch

Abstract: Utilizing a signal from transistor transistor logic (TTL) circuits, the integrated power switch (IPS) can control 40 kW. Protection against overload conditions enables the use of transistors which have ideal switching characteristics. Each half-section of the IPS is electrically isolated from the signal input using optical couplers. Discrete component assemblies, printed-circuit boards, thick-film or medium-scale integrated substrates each have been utilized. The forced-air-cooled heat sink was designed for maximum cooling. Two types of IPS's were initially constructed: 500 V/60 A, and 100 V/200 A, with additional availability of 500 V/100 A devices in small quantity. Its capability to work from continuous operation to 10 kHz makes the IPS universally applicable to most power-conversion applications with-in its current and voltage limitation.

Circuit for light-integrator-controlled electronic flash unit

Abstract: The flash unit includes a flash element and a first electronic switch connected in the current path of the flash element. The flash element is ignited by rendering the first switch conductive. Flash-terminating circuitry terminates the flash by rendering the first switch non-conductive. The flash-terminating circuit includes a commutation capacitor and a second electronic switch interconnected with each other and with the first switch for applying the commutation capacitor voltage to the first electronic switch as a reverse-bias voltage when the second electronic switch is rendered conductive. The second electronic switch is a two-electrode electronic switch which can be rendered conductive by raising the voltage across its electrodes above the value at which such voltage is normally maintained. A light-integrating device detects the light emitted by the flash element and when such amount has reached a predetermined value renders the second electronic switch conductive by raising the voltage across the electrodes of the second electronic switch.

Method of manufacturing an electro-optical switch

Abstract: A method of manufacturing an electro-optical switch in which a metal layer is deposited on a substrate of ferroelectric material and etched to expose the substrate in the form of two channels disposed parallel over a given length. A second layer is then deposited upon the metal layer and the channels, with the diffusion into the substrate of the second layer forming two zones having optical refractive indices greater than that of the substrate. The assembly is then heated and a biasing voltage applied to create remnant electrical polarizations in opposite senses. After removal of the bias voltage, the assembly is cooled and the metal layer removed.

Electrically controlled optical switch

Abstract: The invention relates to switches which enable connections to be optically established between at least one incoming electrical circuit and one of several outgoing electrical circuits. It comprises associating at least one electrical light source, a thin magnetic layer forming a diffraction network and photoelectric receivers, the thin layer enabling the light beam issuing from the source to be directed onto the receivers selected.

Output retaining electronic circuit

Abstract: An electronic switch circuit and a pulse generator are connected in series between a positive and a negative power line. The switch circuit is, once triggered, rendered conductive and retains its conductive condition as long as left alone. The pulse generator automatically renders the conductive switch circuit non-conductive at a preset later time. An output can be derived in the form of a pulse from the pulse generator only while the switch circuit is conductive.

Switch means for cameras

Abstract: A switch means for electrically operating a device in a photographic camera is composed of a mechanical switch and a semiconductor switching element connected with the mechanical switch. The mechanical switch has a pair of contacts made of resilient conductive material and increases its conductivity as the pressure applied thereto increases. By the increase of the conductivity of the mechanical switch an input voltage supplied to the semiconductor switching element is raised and the switching element is turned on when the input voltage has reached a predetermined level. Thus, chattering and large consumption of electric power are prevented.