Abstract: A power conversion circuit is operated at high frequency in the radio frequency spectrum to utilize adjunct reactive impedances of the active semiconductor devices as part of an impedance transformation circuit. Power is transferred through the converter at substantially a single frequency. Energy storage of the adjunct reactances is positively utilized to limit power dissipation within the converter.

Abstract: Semiconductor light emitting devices, lasers and LEDs, are described in which the current flow channel is narrower near the top surface of the device and wider at its bottom near the active region. Also, described are several attenuation masks for fabricating the channels of these devices by particle bombardment.

Abstract: Control circuitry used with the combination of a control switch (typically a gated diode switch GDS) which is coupled to a control (gate) terminal of a like load switch which consists essentially of first and second p-n-p transistors. The collector of the first p-n-p transistor is coupled to an anode of the control switch. The emitter of the first p-n-p transistor is coupled to the base of the second p-n-p transistor and to a control circuitry input terminal. The collector of the second p-n-p transistor is coupled to a gate terminal of the control switch. The control circuitry limits undesirable current flow into the load switch and has fewer components than commonly used control circuitry which performs a like function.

Abstract: A light emitting diode designed to emit primarily at 1.3 microns comprises a crystal having a plurality of lattice matched layers including an n-type indium phosphide front surface layer, an n-type indium phosphide buffer layer, a p-type indium gallium arsenide phosphide active layer, a p-type indium phosphide confining layer and an indium gallium arsenide back surface layer, and an annular front contact and a limited area back contact to the crystal.

Abstract: A ring-trip detector circuit is disclosed which detects a subscriber off-hook condition in the presence of a ringing signal. The ring-trip detector employs substantially all low-voltage components which enables it to be fabricated using integrated circuit techniques with the resultant cost and space-saving advantages inherent therein. The ringing signal is disabled upon detection of a DC component which is present in the telephone loop only when the subscriber goes off-hook. This circuit detects the DC voltage component across a resistor (20) in series with the ringing source (19) and the telephone loop (12, 13). The voltage across this resistor (20) is converted by resistance networks (23, 24) into two relatively small currents that are fed to low impedance points (25, 26). A difference current is formed therebetween, which is filtered (31, 45) to remove AC components, and compared with a threshold current (29, 46). Ring-trip occurs when the filtered difference current exceeds the threshold.

Abstract: A low-loss single mode fiber with low total dispersion within the wavelength range 1.25-1.385 .mu.m and low added cabling loss is disclosed. The fiber has relatively high .DELTA. to assure low cabling loss. The high .DELTA. is obtained, however, without paying a cost in high material dispersion by providing at least 20 percent of the .DELTA. by down-doping of the fiber cladding.

Abstract: The inventive multimode fiber has total loss at an operating wavelength of at least about 0.8 db/km, typically not more than 5 db/km. At least 0.3 db/km, preferably 0.5 db/km, of the loss is due to the presence in the fiber of radially nonuniformly distributed attenuation centers, with the concentration of the centers differing by at least about 10% between the concentration minimum and the maximum. The resulting differential mode attenuation can lead to fiber having larger bandwidth than analogous fiber without differential attenuation. Preferred distributions of attenuation centers have the concentration maximum either at or near the fiber axis, or at or near the core/clad interface. Preferred attenuation centers are absorbers, with OH being a preferred absorber.

Abstract: In a double-clad, single mode fiber with depressed inner cladding, reduced losses at the longer wavelengths are realized when the ratio of the radius of the inner cladding to the radius of the core is at least 6.5 to 1.

Abstract: In a planar ac plasma panel, display cells are formed by the intersection of row and column conductors which are embedded at lower and upper levels, respectively, in a single dielectric layer which adjoins an ionizable display gas. A glow suppression pad, embedded at the upper level, is located adjacent each display cell. The glow suppression pad is capacitively biased from the row and column electrodes at a voltage which prevents unwanted ionization of the display gas between adjacent display cells.

Abstract: A telephone switching office is disclosed having a public announcement system wherein new announcements can be recorded or priorly recorded announcements can be updated via the telephone network. The producer dials a number associated with the announcement to be updated and transmits the update announcement to the office. In order to verify the announcement with an authorized party, the switching office calls the producer at a preassigned station and plays back the update announcement. If the producer disconnects before the playback is completed, the playback announcement is aborted; otherwise, the new version is made active and the former announcement is removed from service.

Abstract: In traditional copper electroplating processes, soluble copper anodes are used as the source of copper. There are certain potential advantages to using nonconsumable anodes and adding a source of copper such as copper oxide to replenish the electroplating bath. Periodic reverse current plating is used by some manufacturers to obtain smoother deposits without the use of additives. This periodic reversal of current drastically reduces the service life of the nonconsumable anodes because of dissolution of the metal oxide on the insoluble anode. The invention is a copper electroplating process with a dual-element anode assembly. This assembly consists of electrically isolated copper and metal-oxide electrodes. The metal-oxide electrode is active only during the anodic part of the cycle while the copper electrode is active only during the cathodic part of the cycle. Electrical isolation is achieved by the use of diodes or relays.

Abstract: A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks.

Abstract: A semiconductor laser is disclosed wherein a grid-like conductive current mask is fabricated between the active region of the laser and one of its electrodes. In one embodiment, the conductive current mask is fabricated in the bottom regions of a corrugated pattern that is created along the length of the semiconductor laser. In a second embodiment, the conductive current mask is totally embedded within a lightly doped buffer layer that is grown proximate to the active region.

Abstract: Improvements in the lateral recrystallization of semiconductor material on buried insulator are disclosed. In particular, in the zone-melting process applied to seeded Si, it is found that scanning the molten zone in a [110] direction can result in substantially subboundary-free recrystallized material. Furthermore, appropriate patterning of the capping layer, to provide means for accommodating the volume change attending solidification of the semiconductor material, can result in significant decrease of defect density in laterally recrystallized semiconductor material on insulator. Especially advantageous results are produced when combining the improvements.

Abstract: A snap-together housing is disclosed having a single fastener holding the multi-part housing together. The housing has a base, around which upper and lower panels fit in a clamshell arrangement. The wrap-around panels provide design contours and are the color bearing elements of the housing. Easy installation is achieved by a tab positioned at the rear of the lower panel which allows the lower panel to rotate upward around the base. A tab on the inner front surface of the lower panel engages a detent on the front of the base thereby preventing the lower panel from rotating downward without first being laterally separated from the base. The upper panel, held in position by a single fastener, interlocks with the front surface of the lower panel to prevent the lateral separation.

Abstract: There is disclosed an office communication system adapted to handle both bursty and continuous data transmission over a single transmission facility to a central switching network. A programmable station controller is used at each station location to interface a number of transmission inputs to the single communication link. The programmable station controller is arranged to statistically multiplex the inputs associated with the bursty data while allowing the continuous data to pass on dedicate time slots. Transmission compatibility between the types of data transmission received from the bursty and continuous data inputs is assured by subdividing the transmission on the single link into frames having four time slots. A fixed number of time slots of each frame are assigned by a central controller to active ones of the continuous data inputs while other time slots of each frame are assigned to the multiplexed bursty data inputs.

Abstract: Materials that change crystal structure upon radiation with a beam of electrons have been found. These materials, such as perylene dianhydride, naphthalene dianhydride, and perylene tetracarboxylic diimide based compounds undergo a transformation from one crystalline structure to another upon exposure to energetic electrons. This transformation causes a change in optical, electrical, and solubility properties. In this manner, these materials are useful as resists for delineating patterns, as optical storage media, and/or in processes for producing patterns of conductive materials such as employed in semiconductor technology.

Abstract: Photodiodes (10) are fabricated in a single step diffusion process which exploits the characteristic of certain acceptors to form an anomalous diffusion profile (VI) including shallow and deep fronts (VIa and b) joined by an upwardly concave segment (VIc). By performing this type of diffusion into a low-doped n.sup.- -type body (12) with a carrier concentration (VII) below that of the concave segment, a p.sup.+ -p.sup.- junction (15) is formed at the depth of the concave segment and a p.sup.- -n.sup.- junction (17) is formed at a greater depth. The zone (16) between the junctions is at least partially depleted and forms the active region of a p.sup.+ -p.sup.- -n.sup.- photodiode. Specifically described are InP:Cd photodiodes.

Abstract: The combination of an amplifier with a capacitor connected between an input and output terminal is coupled to a data bus to effectively reduce the effective capacitance on the bus and thus enhance the response time of information sent through the data bus.