Showing papers on "Optical switch published in 1979"

Optical multiplexer and demultiplexer

Abstract: An optical multiplexer and/or optical demultiplexer for multiplexing and/or demultiplexing a plurality of wavelengths comprises a plurality of optical filters each of which transmits a predetermined wavelength and reflects other wavelengths, said optical filters being arranged so that an optical beam is transmitted or reflected via each optical filter in sequence in a zigzag fashion. A light source or light detector is provided behind each optical filter to project or receive a collimated optical beam. The angle of incidence when a beam is applied to an optical filter is small. And, another optical means is provided to connect the present optical multiplexer and/or demultiplexer with an outside optical fiber. The transmission wavelength of each optical filter is different from the others.

Polarization‐independent optical directional coupler switch using weighted coupling

Abstract: We report the first demonstration of a guided‐wave polarization‐independent electro‐optic switch. Using a specially designed weighted Ti‐diffused directional coupler with stepped electrodes, we have achieved crosstalk levels below −23 dB for both switch states for arbitrary incident optical polarization.

Piezoelectric optical switch

Abstract: A piezoelectric optical switch includes a piezoelectrical element having an optical fiber affixed thereto. A second optical fiber is placed in general proximity to the first optical fiber so that, upon application of a first voltage to the piezoelectric element, the optical fibers are caused to be aligned, and wherein upon application of a different voltage to the element, the optical fibers are caused to be nonaligned. The switch can include a nonpiezoelectric cantilever beam having a fixed end and a free end and adapted to be bent along an axis adjoining the two ends. One optical fiber is affixed to the beam. A plurality of optical fibers, each in general proximity to and each adapted to be selectively aligned with the one optical fiber, is provided. A piezoelectric bending element, having opposite ends coupled to fixed supports, has a medial portion coupled to the cantilever beam near the fixed end. Thus, upon application of a first voltage to the bending element, the first optical fiber is caused to be aligned with a specific one of the plurality of optical fibers. Upon application of a different voltage to the bending element, the first optical fiber is caused to be aligned with a specific different one of the plurality of optical fibers.

Mechanical optical switching device

Abstract: The mechanical optical switching device comprises an input optical fiber with a collimating lens (5) and a first and a second output optical fiber each with a converging lens (6 and 7, respectively) at the respective terminal ends. Further there are provided a movable first optical path-changing means (8) and a fixed second and a fixed third optical path-changing means (12 and 13) associated to the first and second output fiber, the three path-changing means (8, 12 and 13) comprising two reflecting surfaces each. For performing the switching operation the first optical path-changing means (8) may be inserted into the optical axis of the collimating input lens (5) or removed therefrom. In the removed position the input beam is directed towards the second output fiber via the third path-changing means (13) and the second output lens (7), and in the inserted position the input beam is directed towards the first output fiber via the first path-changing means (8), second path-changing means (12) and the first output lens (6) Preferably the first path-changing means (8) is a parallelogram prism with the two reflecting surfaces opposite to each other and the second and third path-changing means (12 and 13, respectively) are triangle prisms.

A GaAs MESFET Sample and Hold Switch

Abstract: A monolithic GaAs MESFET sample and hold switch has been designed, primarily as a research vehicle for GaAs linear integrated circuit technology. A novel FET-ring circuit configuration has been used in order to overcome the problems associated with switch drive in more conventional circuits.

Optical isolation circuit for bidirectional communication lines

Abstract: In an improved optical isolator circuit for interfacing a modem or other data transceiver and the telephone lines, first and second optical paths are established by pairs of semiconductor, optical couplers connected between the modem and telephone lines. While the first optical path carries outgoing data from the modem to the lines, negative feedback on the second optical path provides bias stabilization of the optical couplers and associated circuitry. Similarly, while the second optical path carries data incoming from the lines, there is stabilizing, negative feedback on the first optical path. A high open loop gain, closed loop circuit strategy incorporated in the isolator provides wide band, linear operating characteristics without matched optical couplers.

Touch sensitive electric switch

Abstract: An electronic switch has a sensor input responsive to a person's touch. Manual contact is sensed by a CMOS input of a one-shot multivibrator initiating the output which is used to toggle a flip-flop circuit off or on. The flip-flop output is connected to the trigger circuit of a silicon controlled rectifier, which in turn completes a circuit through a load. The switch may be a single pole, single throw switch, or if flip-flops are connected together in cascaded arrangement, a three position switch is formed.

Switch for optical transmission lines

Abstract: Disclosed is an optical switch for changing over the mode connecting two optical transmission lines comprising two optical fibers directly to each other and the mode connecting an optical communication device between the two transmission lines. In this optical switch, in order to reduce the insertion loss, first, second, third and fourth optical fibers, each having an optical connector attached to one end, are attached to a substrate so that at least parts of the respective optical fibers are fixed to the substrate, and the ends of the first and second fibers are arranged on the substrate movably so that the end face of the first optical fiber confronts the end faces of the second and third optical fibers and the end face of the second optical fiber confronts the end faces of the first and fourth optical fibers.

Integrated bistable optical device using mach-zehnder interferometric optical waveguide

Abstract: An integrated mirrorless bistable optical device based on the Mach-Zehnder interferometric optical switch has been proposed and demonstrated experimentally using a Ti: LiNbO3 waveguide. The resulting device is capable of combining more than two of them to realise multifunctional optical devices such as optical multivibrators.

Optical switch for multimode optical-fiber systems.

Abstract: A new type of optical switch is constructed of graded-index rod lenses. It is operated mechanically by small electromagnets. This switch is compatible with practical multimode-fiber communication systems. It has many outstanding features, such as low insertion loss (1.3–1.4 dB), low crosstalk ( 2 × 106 times), and small size (40 × 50 × 25 mm3).

Semiconductor high-voltage switch

Abstract: A high voltage, fast acting electronic switch is formed from a reverse-biased PIN diode having an exposed intrinsic region, together with a controllable optical source for emitting radiation directly onto the intrinsic region to switch the diode from its non-conducting state to its conducting state.

A 1 Gbit/s integrated optical modulator

Abstract: A waveguide directional coupler modulator is demonstrated with a bandwidth of 1 GHz and a rise time of 590 ps. An analysis of the electrical parasitics is presented and the device response is found to be transit-time limited. The scaling of the frequency response is shown to be characterized by a bandwidth-length product of 1.1 GHz - cm.

Optical switching and bistability in tunable lasers

Abstract: We report the observation of optical switching and bistability, and such related effects as hysteresis, optical memory, multistability, and differential gain, in an electro‐optically tuned cw dye laser. Similar effects should be observable in other tunable lasers.

Ridge waveguides and electro-optical switches in LiNbO 3 fabricated by ion-bombardment-enhanced etching

Abstract: Narrow ridge waveguides with \sim 2-\mu m width have been fabricated in Ti-diffused LiNbO_3 by ion-bombardment-enhanced etching and the intensity modulation by switching the waveguide from guided mode to radiation mode through electro-optic effect has been demonstrated. The extinction coefficient of -19 dB was obtained at the applied voltage of \pm 10 V.

Solid state circuit breaker with three phase capability

Abstract: A solid state circuit breaker is provided with circuitry for permitting off/on/reset operations actuated by mechanical toggle switch for close simulation of magnetic circuit breaker operation in three phase or other multiphase systems. A power continuity feature is provided for load power by locating the control switch so that it opens all of the circuit except the static power switch branch. The control switch is located between two of the supply voltage phases and the power supply for the control circuitry. The correct zero crossover of one phase is utilized to produce turn-on at zero degrees of that one phase while the other two phases are respectively at minus 120° and plus 120° without any significant impairment of overall circuit breaker performance. An overcurrent protection system is included that uses optical isolators with reduced sensing voltages developed directly from terminals of the power switch elements.

Fluid optical switch for a solar collector

Abstract: Apparatus for optical switching which uses a fluid medium whose refractive index is matched to that of a highly dispersed optical scattering layer to provide optical transparency of said scatterer when immersed in the fluid media and optical reflection in the absence thereof. The fluid optical switch is embodied in a solar energy collector to provide overtemperature protection to collector components and further to provide a convenient means for turning off the collector during periods of nonuse.

Two terminal power control switch with triac current powered control means

Abstract: A switching arrangement including a current switch for providing a low impedance electrical path therethrough in response to the application of triggering signals thereto, and for providing a high impedance electrical path in the absence of the triggering signals, is connected in an electrical path between a load and an AC voltage source. A control circuit is provided for applying triggering signals to the current switch when enabling power is applied thereto. A normally open switch provides enabling power derived from the AC voltage source to the control circuit when the normally open switch is closed. A normally closed switch provides enabling power derived from current which flows through the current switch to the control circuit when the normally closed switch is closed. Upon momentary closure of the normally open switch, the switching arrangement is turned on. Upon momentary opening of the normally closed switch, or upon the momentary interruption of the AC voltage supplied to the switching arrangement, the switching arrangement is turned off.

Fused short circuit and grounding switch

Abstract: A fused short circuit and grounding switch for interconnection in a main circuit, the switch having a switch member operable in one position thereof as a part of the main circuit and operable in another position out of and breaking the normal continuity of the main circuit therethrough and to provide a solid bolted fault, and including an alternate circuit interconnected to and operable to be in parallel with the main circuit, the alternate circuit being fused, the switch being operable to short circuit the alternate circuit and clear the fusing thereof and to thereby interrupt the main circuit on operation of the switch member to the position thereof providing a solid bolted fault.

Electronic light switch

Abstract: The specification discloses an electronic switch for operating an incandescent lamp from a plurality of stations. A plurality of normally closed mechanical switches may be wired in series with the lamp, and electronic switch to form a single series circuit. Actuation of any single mechanical switch interrupts the power, causing the electronic switch to change its state. Additional circuitry for dimming and state preservation in the event of a complete power failure are also disclosed. The rate at which power is applied or reduced may be varied in accordance with circuit values.

Optical Switching System Experiment

Abstract: The construction and experimental results of a tiny optical video switching system are described. It had a 4 × 3 switch network composed of seventeen 1 × 2 type meehanical optical fiber switches whose average loss was 2.6 dB. Network insertion loss was about 20 dB. Insertion loss cause, signaling method and improvement for practical use are discussed.

Libido using Eros: half-duplex optical link

Abstract: A half-duplex optical link Libido (Liaison bidirectionnelle optique) has been realised using the optimised semiconductor optical transceiver Eros (Emitter-receiver for optical systems). The digital transmission has a bit rate of 10 Mb/s with a biphase code using a step-index plastic-clad silica fibre. The characteristics of the component and the link are presented.

An Avalanching Optoelectronic Microwave Switch

Abstract: A new optoelectronic microwave switching device is described. The device is composed of a Semiconductor junction diode that is incorporated into a transmission line and illuminated with optical pulses from a semiconductor laser. Switching of microwave signals is achieved by changes in the RF impedance of the diode's high-field region resulting from an optically induced switching between low and high-level avalanche states. Experimental results demonstrating the switching characteristics and speed of this device are presented along with a basic theory of operation. The ultimate capabilities of this device and its advantages over conventional p-i-n diode switches and other optoelectronic switching devices are also discussed.

Light source system in an optical transmission repeater

Abstract: An optical transmission repeater with high operational reliability comprises of a plurality of light sources for transmitting an optical energy into an optical fiber, an optical connector for introducing the optical energy from each of said light sources to an optical transmission line, and a switching circuit for selectively operating only one light source. When a light source in operation is deteriorated, the light source in operation is switched to another light source by said switch. Thus, high operational reliability of an optical repeater is obtained although each of light sources have a low operational reliability.

New automatic-gain-control system for optical receivers

Abstract: A device using liquid crystals can be readily inserted in existing optical communications to simplify receiver circuitry, allow planning flexibility and simplify maintenance.

Optical switch array

Abstract: PURPOSE:To obtain easy-to-manufacture optical switch arrays, by providing a first optical guide and a second optical guide branched therefrom in an electro- optical crystal, and composing the connection part in a high refractive index waveguide part. CONSTITUTION:A voltage is applied by an electrode 41 to a plane at an angle of theta with respect to the boundary of a high refractive index waveguide Wa1 and an optical guide 13, that is, with respect to the running direction of light. In this case, unless voltage is applied to the electrode 41, the incident light from direction 1 mostly runs in direction 3, or in the direction of optical guide 13. Hence, by applying proper voltage to the electrode 41, the incident light from the direction 1 may be mostly led in direction 2 shown by solid line, so that the light switching may be possible. The same applies to other electrodes 42, 43. Further, by composing more branching circuits, the light switching may be easily constituted.

Fiber optic rotation sensor technology

Abstract: A concept for an all-waveguide fiber-optic rotation sensor is discussed, and the results of preliminary tests of key elements are described. A single channel waveguide coupler design provides the functions of an optical switch, a 3-dB beam splitter, a phase retarder, and a signal modulator, all of which may be formed on the same chip and interconnected by channel single-mode waveguides. Preliminary test results for the waveguide coupler and for a rotation sensor without the coupler are presented. Signal processing, polarization control, and interconnection of the waveguide components are discussed.

Optical switching in metal tunnel-insulator n-p + silicon devices

Abstract: This paper considers the mechanism of optical switching and the possible utilisation of the metal tunnel-insulator n-p+ silicon device in optical communication systems. The pertinent design approaches are described. Under optical excitation, photo holes and electrons generated in the surface depletion region, or within diffusion range, will eventually be separated by the electric field and produce an increment in the forward current. Those hole-electron pairs generated in the junction region, or within diffusion range, produce a photovoltaic increase in the p+-n junction bias. Switching is induced optically, as it is electrically, by the build up of holes at the insulator-semiconductor interface. This paper employs the 1-dimensional diffusion equation to derive the light generated minority Carrier distributions and diffusion currents in the neutral n and p+ regions, together with the currents in the surface and p+-n junction depletion regions. The calculated values of both the drift and diffusion currents compare favourably with those observed experimentally.

A switching circuit

Abstract: A switching circuit (1) has a solid state power switch (9) which is either a PNP or NPN transistor or a VMOS p-or n-channel device. Three individual sensing circuits (2, 3, 4) are set to indicate whether a predetermined operating characteristic of the switch (9) is greater or less than a given threshold value and thus to indicate if a fault is present in the switch (9) or the load (L) it supplies. Digital logic circuit means comprising three logic circuits (5, 6, 8) produce two digital signals (D, P) from the output signals of the sensing circuits respectively indicating if a fault exists and if it is a serious fault or not. A circuit (7) comprising gating means disables the switch (9) in the event of a serious fault and a delay circuit (33, 34) is provided associated with the logic circuit means to prevent current surges due to short circuit faults being confused with normal operating current surges in switch on.

Loop type data highway system using optical fiber

Abstract: PURPOSE:To enable to make long the distance between stations even if a certain attenuation is present at the optical switch section, by tentatively increasing the transmission power of the prestage station for the by-passed station at by-pass. CONSTITUTION:On the closed loop formed with the optical fiber data highway 1, the data transmission and reception sections on which the fiber selectors 10, 20, 30 and the repeaters 11, 21, 31 are respectively provided are in cascade connection. If the remote station 22 and the repeater 23 are in failure, the optical switch is selected to by-pass side and the selection instruction 201 is given to the remote station 12. After that, the selection instruction increases the optical output of the remote station to maximum output to enable the transmission to the remote station 32.

A Look at Optical Fiber CATV

Abstract: When will optical fiber CATV replace coaxial CATV? A study of current literature shows that the time is not yet, although optical fibers have been used for supertrunks and other special purposes. The purpose of the author is to examine some of the calculations which can be used on optical CATV systems as well as some of the improvements necessary for widespread use of optical CATV systems.