Abstract: A polarization mode dispersion measuring apparatus includes a variable wavelength light source for providing light of a variety of wavelengths; a light intensity modulator optically connected to the light source to provide light of modulated intensity; a polarization controller optically connected to the light intensity modulator to provide light of controlled polarization; a beam splitter optically connected to the polarization controller to provide beams of p and s polarization components; an O/E conversion unit optically connected to the beam splitter to provide electrical signals with respect to the beams of the p and s polarization components; and an analyzing unit for controlling the light intensity modulator to provide a sine wave of a predetermined frequency and a predetermined intensity, and the light source and the polarization controller to determine parameters of Jones matrix from the electrical signals and a polarization mode dispersion defined by the parameters, thereby measuring a polarization

Abstract: A method and system for retrieving images using a coupled knowledge-base/database is provided, the method comprising the steps of modeling structural knowledge by identifying classes and attributes of classes, determining relationships among the classes, operations for each classes; modeling heuristic and general procedural knowledge by acquiring heuristic rules for each class dependent on the application domain, specifying data processing procedures required by the heuristic rules acquired; modeling control knowledge by specifying intra-class-hierarchy searching paths, specifying intra-class-hierarchy searching paths, and representing the specified search paths in triggers for each class; and deriving a schema for the coupled database from the structural knowledge.

Abstract: An optical network analyzer measures the amplitude characteristics and group delay time dispersion characteristics of an optical circuit device. In the optical network analyzer, the intensity of the light generated by a first light source is modulated by use of a modulation signal having a constant frequency and a constant amplitude. Part of the intensity-modulated light is used as a reference optical signal, and the remaining part is made to pass through the optical circuit device, thus obtaining an optical signal to be measured. The reference optical signal and the optical signal to be measured are photoelectrically converted into electric signals, and the modulated signal components of the electric signals are compared with each other, thus obtaining an amplitude ratio and a phase difference. The optical frequency of the first light source is swept in a constant cycle, and the amplitude ratio and phase difference are displayed on a display device in synchronism with the frequency sweeping.

Abstract: A digital signal exchange equipment is disclosed which is constructed of a combination of selector modules each constituted by a plurality of gate arrays as a parallel unit in a column direction. The respective gate array comprises a first gate for selecting one line from an n number of first input lines and connecting it to an output line, a second gate for selecting one line from an output line of the first gate and one second input line and connecting it to the second gate and a flip-flop for wave-shaping an output of the second gate and, at the same time, taking synchronization among the respective gate array. The selector module as set forth above is constructed of a semiconductor circuit device. When, in particular, a plurality of selector modules are combined together, they are arranged as a k-column/l-row array in which input bus lines are each connected to each common row and an n number of output lines are connected for each row to an n number of second input lines of the next-row selector module.

Abstract: When a light wave passes through an optical fiber used as an optical communication line, different time delays are introduced in its frequency components according to the delay characteristic of the optical fiber, limiting the usable bandwidth. An optical equalizer according to the present invention comprises a multi-stage connection of one or more unit optical circuit elements for introducing time delays opposite to the delay characteristic of the optical fiber in frequency components in the neighborhood of the transmission band used. The optical equalizer is placed at the input end of a transmission line and equalizes time delays of the frequency components passing through the transmission line, thereby expanding the usable bandwidth.

Abstract: An integrated multimedia network system is constructed by a plurality of transport nodes each having several types of communication media intervened at arbitrary locations in a ring-shaped transmission path. One transport node exchanges communication information of communication media in a fixed-length packet transfer format. The transport node has a packet switcher, which divides packets into plural groups for at least self node and other nodes by switching between media communication packets from the self node and those packets from an adjoining transport node based on header information that indicates their destinations. A group of packet communication information destined to the self node is sent to the associated communication medium. A group of packets for other nodes is time-divisionally multiplexed and is sent on the transmission path.

Abstract: An array antenna apparatus having plural antenna elements includes a control signal generator which generates a control signal including signal generating data and signal controlling data. Each of plural dividers corresponding to the plural antenna elements divides the control signal into the signal generating data and the signal controlling data. Each of plural signal generators corresponding to the plural antenna elements generates a defined signal corresponding to the signal generating data. Also, each of plural drivers corresponding to the plural antenna elements produces a specified signal, corresponding to the defined signal and the signal controlling data, through each of the antenna elements.

Abstract: A device for amplifying an input optical signal includes an optical amplifier having a gain control region in which the input optical signal is amplified, a first detecting region for detecting the input optical signal, and a second detecting region for detecting an amplified optical signal. The gain of the optical amplifier is controlled by a gain control signal from a signal source. A controller, responsive to detecting signals from the first and second detecting regions, produces a source control signal which is supplied to control the signal source.

Abstract: A parallel processing search system for searching and updating a database at the request of a host system, including a master processor connected to a host system bus for transfer of information between said master processor and the host system bus; a data bus connected to the master processor; plural slave processors connected to the data bus for independently processing search respective requests under the control of the master processor; a disk drive interface adapted to be connected to a disk which stores a database; and a buffer memory connected to the data bus and the disk drive for storing the database retrieved from the disk and for sequentially placing data from the database on the data bus for match comparison by the slave processors so that a search of the database can be made by the slave processors under the control of the master processor.

Abstract: In this information transmission system, a PCM encoder is provided for time-division multiplexing multichannel audio signals and a digital character information signal to generate a time-division multiplexed, or TDM, information signal. The TDM information signal is angle-modulated by the modulator to generate an angle-modulated information signal. This signal is supplied to a frequency-division multiplexer, which multiplexes the angle-modulated information signal and an image signal so as to generate a frequency-division multiplexed, or FDM, information signal which is adapted to be supplied to a certain subscriber.

Abstract: According to a scan planning method for obtaining any tomographic image by a CT system, projection data of a plurality of parallel slices is acquired by a computed tomographic scanning device. The tomographic images are interpolated in accordance with the tomographic data of the slices which is obtained by the CT scanning device thereby providing the three-dimensional image data. A three-dimensional object image is then displayed on a display in accordance with the three-dimensional image data. A viewpoint for the object image changes, and an orientation angle of the object image changes in accordance with a manually input coordinate information. A slice position image representing the designated position and angle of the slice is displayed three-dimensionally in accordance with the coordinate information. The CT scanning device is controlled in accordance with the position and angle of the slice position image with respect to the object image.

Abstract: A composite optical semiconductor device which includes a light emitting element and a light detecting element formed in a single body. The light detecting element is formed in the shape of a circle, with the light emitting element being formed within the circle. The electrode configuration of the light emitting and light detecting elements is such that the current path of the light emitting element does not overlap with that of the photo detecting element, whereby the light detecting element can obtain an accurate monitoring current indicative of the light emitted from the light emitting element.

Abstract: A contention-type data communication system such as an optical star-configured network comprises a plurality of stations connected with one another through data bus. To detect a signal collision quickly, each of the stations is arranged to transmit a collision-detecting packet which has a predetermined time length T.sub.1 and a predetermined pulse pattern, and then transmit a data packet after a time interval T.sub.2. The number or pattern of pulses received during a time period T.sub.1 +T.sub.2 from the start of reception of a collision-detecting packet is compared with that of the self-transmitted collision-detecting packet so that the signal collision is detected when noncoincidence occurs.

Abstract: In an optical instrumentation system, sensor units are solely constructed optically and each sensor unit comprises a subcarrier generating section for causing periodic changes in the light intensity of light wave from a light source corresponding to the wavelength sweep of the light source to generate a subcarrier, and a sensor section for modulating the subcarrier by detected information, and at the receiving end of the system a demultiplexing section is provided for demultiplexing detected information by selecting the subcarrier.

Abstract: A module for a fiber optic link has a case housing a circuit module plate. An optoelectric element mounted at a predetermined position of lead frames is molded from a transparent transfer molding material. The case has a socket for mounting a fiber cable connector which is molded from a nontransparent injection molding material. A hole in which is inserted a plug of the connector is formed in the socket and the case. The optoelectric element is arranged to oppose the hole of the case through a convex lens segment of the case.

Abstract: An optical communication system includes a plurality of stations and at least two passive optical couplers. Each of the couplers has at least four pairs of ports, each pair including an input port and an output port. An optical signal inputted to any one of the input ports is outputted to all of the output ports except the output port of the pair into which the optical signal was inputted. A plurality of optical signal transmission lines interconnect the passive optical couplers and connect the passive optical couplers to the stations. Passive optical couplers of both the transmission type and the reflection type are disclosed. The transmission type passive optical couplers rely either upon the direct interconnection of the appropriate input ports and output ports or upon diffraction to guide optical signals to the correct output ports.

Abstract: A pair of optical fibers are arranged parallel in contact. A portion of the pair is thermally fused to form a biconical taper waist. The biconical taper waist is cleaved at its thinnest portion, thus dividing the pair of optical fibers into two sections each having a tapered portion at one end. One of the sections is rotated by 90.degree., and its tapered portion is butted on the tapered portion of the other section, while keeping the axes of both sections aligned. The tapered portions thus butted are then thermally fused to couple the sections together, thus providing an optical power distributor. At the thinnest portion of the waist, one of the cores of one section overlaps both cores of the other section.

Abstract: A light distributor comprising a plurality of optical fibers each having a tapered portion, said tapered portions of the optical fibers being thermally fused together to form a light mixing section where the cores of the fibers are packed together in a single cladding.

Abstract: A laser apparatus including first and second frequency sweeping laser devices, the sweep frequency range of each being different. The output laser beams of the first and second laser devices are multiplexed by a multiplexer. The output laser beam of the multiplexer is transmitted to a photodetector for detecting the difference in frequency between those of the first and second laser devices. A frequency monitor, coupled to the photodetector, provides a signal to a control circuit which causes the first and second laser devices to sequentially sweep their respective sweep frequency ranges.

Abstract: In an optical sensing system a laser beam is split by a 3dB optical directional coupler into two beams which in turn are launched into single mode optical fibers of different lengths. Since the two single mode optical fibers are maintained at the temperature to be measured, a phase difference is produced between the beams transmitted through the optical fibers. The beams passing through the optical fibers are synthesized by the 3dB optical directional coupler to form an interference pattern comprised of "light" and "dark" regions. The wavelength of the light beam is monotonically varied over a predetermined range so as to cause these regions to vary in position. This variation in position is manifested at a given point in the interference pattern as a variation in signal amplitude, and this variation in signal amplitude is detected to infer the temperature to be measured.