Abstract: The present invention relates to a method of mitigating gain peaking in a chain of fiber amplifiers by pumping the amplifiers at a predetermined wavelength to produce gain over a specified wavelength range.

Abstract: A flowmeter for determining the amount of flowing medium using an orifice (4) and a resistor body (5) in a cavity (6) through which the medium to be measured flows. Not the resistor body (5) but an orifice sleeve (4) is displaced as a consequence of the varying primary pressure and thus the degree of opening of the flow orifice is determined depending on the amount of flow of the flowing medium. A satisfactory linearization of the subregion of the function .DELTA.p (V) is obtained.

Abstract: A faulty operation prevention circuit for an infrared-ray remote controller comprising inverter for inverting a transmission signal from the infrared-ray remote controller, a first pulse generation circuit for generating pulses in response to an output signal from the inverter, each of the pulses having a first width, a noise identification unit for identifying an optical noise contained in the transmission signal from the infrared-ray remote controller in response to the output signal from the inverter and the output pulses from the first pulse generation circuit, the noise identification unit having first and second transistors, and a second pulse generation circuit for generating a pulse in response to an output signal from the noise identification unit, the pulse having a second width.

Abstract: A float type flowmeter including a bottom flow-through fitting and an upper flow-through fitting in spaced relationship with the bottom flow-through fitting; and an exchangeable measuring tube extending between the fittings. Each fitting has an opening formed as a cylindrical recess in alignment with each other with the openings each receiving a respective opposite end of the measuring tube. An external guide on each end of the measuring tube is in close fit with respectively an adjacent cylindrical recess, thereby facilitating axial movability of the measuring tube within predetermined limits in the longitudinal direction of the measuring tube. A distributor head having mutually communicating axial and radial ducts is located in the upper flow-through fitting closely above the upper end of the measuring tube; and a sealing closure screw operative in conjunction with an axial stop is provided for limiting the vertical axial movement of the measuring tube between the fittings.

Abstract: A pitot of the type adapted to be positioned in a stream of moving fluid such as an air duct and accurately measures wide variations in flow rate. A first plate with opposing sides and opposing leading and trailing edges and a second plate has opposing sides and opposing leading and trailing edges. The plates are parallel to each other and are in overlying spaced relation. A first tube has a proximal end and a distal end and is connected in sandwich fashion between the first and second plates proximate the leading edges. The tube has a plurality of holes defining openings located proximate the leading edges of the plates, the holes being perpendicular to the plate surfaces. A second tube has a proximal and a distal end and is also connected in sandwich fashion between the plates, parallel to the first tube, proximate the trailing edges of the plates. Also provided are holes defining openings in the tube that are parallel to the surface of the plates.

Abstract: An apparatus measures the mass of a tube and liquid contained in the tube. A stiff beam is fixed at one end and connected to the tube with a magnet thereon. An electric circuit generates a current pulse which vibrates the beam and tube and induces a natural response therein. Movement of the magnet on the beam induces a current in the circuit with the induced current having a frequency of oscillation equivalent to the natural frequency of vibration of the tube and liquid in the tube. The electric circuit includes a comparator and a counter, with the comparator receiving the current induced by movement of the magnet and supplying a pulse signal to the counter having a period equal to the period of oscillation of the beam and the tube. The counter triggers the generation of an additional current pulse after a predetermined number of cycles of the induced current are counted. The current pulses are generated at a frequency lower than the frequency of the natural vibratory response of the beam and the tube.

Abstract: A Coriolis mass flow rate meter for measuring the mass flow rate of material flowing through a conduit. The flow meter includes at least one flow tube through which the material to be measured passes. The flow tube is vibrated at its natural frequency so that the concurrent flow of material through the vibrating tube produces a displacement of the tube with the magnitude of the displacement being dependent upon the magnitude of the generated Coriolis forces and the mass flow rate of the measured material. The phase of the displacement of the flow tube is measured using optical fiber sensors comprising at least one loop of optical fiber which is flexed by the displacement of the flow tube. This flexing of the fiber causes a corresponding change in its optical conductivity and a corresponding change in the intensity of the light transmitted through the fiber from a light signal source to a signal detector.

Abstract: Multiphase fluid flow, such as a mixture of oil, water and gas, is measured by a system which includes one or two densitometers for measuring the multiphase fluid density flowing through a flowline or conduit and a flow restriction, pump, expander or heat exchanger interposed in the flowline between the densitometers to effect a pressure or temperature change in the multiphase fluid. Densities, pressures and temperatures are measured on the upstream and/or downstream sides of the flow restriction, pump, expander or heat exchanger and the measured values of density, pressure and temperature are used to obtain the flow rates of the respective phases in the flowstream.

Abstract: An optical communication system and method are provided which utilize dispersion-induced FM to AM conversion with nonlinearity-induced AM stabilization. The system and method utilize a frequency modulated optical signal transmitter, a fiber span, an optical receiver which receives the transmitted optical signal and detects an AM signal resulting from dispersion-induced energy overlaps and voids in the optical signal, and one or more in-line amplifiers spaced within the optical fiber span. By adjusting the number, position and/or output power levels of the in-line amplifiers, stabilization of the energy voids and overlaps and resulting AM signal can be achieved, yielding a substantial increase in achievable transmission distance at a given bit rate.

Abstract: An automatic frequency control system, for an optical coherent communication system, in which the frequency of local oscillation light 5 from a coherent light communication receiver 100 is swept to pull the intermediate frequency to a stable AFC point. The AFC is caused to operate with an intermediate frequency in the AFC operation range, and interrupted. Subsequently while sweeping the frequency of local oscillation light 5 in a certain direction in a predetermined range, the output voltage of frequency discriminator 9 is monitored. Once the change of the output voltage of frequency discriminator 9 due to the sweep exceeds the predetermined threshold value, the AFC resumes for pulling to a stable point.

Abstract: The present invention provides an apparatus and method for performing polarization-insensitive four-photon mixing of optical signals. The polarization-insensitive optical mixer includes a polarization splitter for splitting an optical signal into parallel and perpendicular polarization components, different mixing paths for mixing a pump signal of like polarization with each of the parallel and perpendicular components in a nonlinear mixing device, and a polarization combiner for combining the resulting mixing products. Certain of the mixing products represent phase conjugates of the input optical signal, and are therefore useful in compensating for chromatic distortion in optical fiber.

Abstract: Optoelectronic switching apparatus employing optoelectronic switching devices interconnected by optical media having different delay lengths and an multiport optical coupler. The optoelectronic switching apparatus provides for a multibit true-time-delay beamsteerer for beamsteering phased array antennas. The present invention combines two types of optoelectronic devices, lasers and photodiode switches, using an interconnected passive optical network comprising the optical fibers and the optical coupler. The switches, and input and output signal networks coupled to the respective switches, are controlled using a control signal generator. Using this scheme, any input can be independently selected and a signal can be routed to any output. Furthermore, the product of the total number of different interconnect paths (N.times.M) is provided which provides a greater number of delay lengths than is provided by using only one type of switch (i.e. laser (N) or photodiode (M)) alone.

Abstract: A Karman vortex flow meter in which a main passage 1 and a bypass passage 2 are adjacent to each other; a throttle portion 12 is formed at the inlet of the bypass passage to continuously reduce the cross-sectional surface area of the passage, and a flared portion 14 is formed in the bypass passage 2 so that the cross-sectional surface area of the passage is continuously enlarged from an intermediate portion of the passage to the outlet of it. Further, the inlets and the outlets of the main passage and the bypass passage are each arranged in single planes perpendicular to the flow direction of the fluid to be measured, and the boundary portions 16, 17 between the main passage and the bypass passage 2 are respectively formed to have a smallest thickness.

Abstract: A fluidic oscillator and a flowmeter comprising means (10, 14, 16) for forming a two-dimensional fluid jet and an obstacle (22) having a main cavity (26) swept by the oscillating jet, and secondary cavities (34, 36) on either side of the main cavity (26) enabling the radial extension of main vortices accompanying the oscillation of the jet to be made dependent on flow conditions. Applicable to the measurement of the velocity or flow rate of flowing fluid.

Abstract: In a passive optical telecommunication system in which the signal transmission from a switching center downstream to remote units proceeds in a first stream on a time-division multiplex basis and in which the signal transmission from the remote units upstream to the central switching center proceeds in accordance with a TDMA method in accordance wherewith a remote unit transmits each burst in a synchronized fashion with the assistance of a delay device that is individually set with respect to each remote unit proceeding from the switching center, the remote unit already transmits the bursts before the transmission time required for a desired reception phase relation of the burst in the central switching center only after a rough delay time of a whole system clock period (or system clock periods), and the switching center centrally undertakes a respective individually-dimensioned fine delay of the bursts incoming thereat from each of the remote units into the desired reception phase relation.

Abstract: The gas flow rate and liquid flow rate of a two phase fluid flow are determined by passing the fluid flow down an inclined pipe to stratify the flow. The fluid pressure, temperature and density are measured along with the liquid density. The differential pressure is measured to determine the dynamic head of the fluid. These measurements are used together to determine the gas flow rate and the liquid flow rate.

Abstract: A fluidic oscillator flowmeter in which a two-dimensional fluid jet oscillating transfersely relative to a plane of symmetry, P, sweeps over the bottom of a cavity, and in which the flow rate is determined by electronic means from a signal, S, corresponding to a differential pressure resulting from the difference between a pressure tapped off at a point, P.sub.3, located on the axis of intersection between the plane of symmetry, S, and the bottom of the cavity and a pressure resulting from tapping off the pressure at two points, P.sub.1 and P.sub.2, which are located symmetrically on respective sides of the plane of symmetry, S.

Abstract: A vortex flowmeter for measuring fluid flow includes a conduit having a wall surrounding a bore for carrying the fluid along a bore axis. A pivoting member moves in response to vortices in the fluid and extends from a hole in the wall into the bore, and sensing means is provided for sensing the motion of the pivoting member to provide a flow indicative output. In one embodiment, a torsional pin is disposed in the hole and couples to the pivoting member, and further has a first pin end attached to the wall. In another embodiment a diaphragm extending across the hole, together with the conduit wall and the pivoting member, are integrally formed from a material so as to present an unbroken overall surface to the fluid and to reduce crevices or gaps in which portions of the fluid can lodge. In another embodiment the pivoting member is at least a portion of a downstream extremity of a body disposed in the bore.

Abstract: A cross-channel data link for interconnecting a plurality of computers together in a ring configuration using a single optical fiber between adjacent communication nodes includes wavelength division multiplexing circuitry in a way that improves the fault diagnostic capabilities of the system. By using a particular transmission protocol in which optical data representing signals of two discrete wavelengths are fed through a single optical fiber with one progressing in the clockwise direction and the other in a counterclockwise direction in two recurring time frames, at the conclusion each of the computers is guaranteed to have identical data irrespective of any single point failure in the data link.

Abstract: A system for stabilizing a frequency separation between two coherent light sources includes first and second current sources driving first and second semiconductor laser devices with first and second frequencies, respectively. Light from the semiconductor laser devices is combined in a multiplexer, and a portion the combined light is diverted to an optical-to-electrical transducer. Output current from the transducer is combined with an output of a local oscillator driven at a selected frequency. A combined signal is then filtered, and used to form a control signal of one of the semiconductor laser devices.