Abstract: A chemical vapor deposition method which utilizes a rare earth chelate vapor as a source of rare earth ions for producing an optical fiber having a core with a high rare earth content.

Abstract: A single mode optical fiber of stepped index of refraction. Both core and cladding are fabricated of pure fused silica doped with a small base percentage of fluorine to substantially eliminate hydroxyl ions and reduce viscosity. In addition to the base amount of fluorine, the cladding contains a further amount for lowering its index of refraction relative to that of the core and for further reducing viscosity.

Abstract: A process for coating a synthetic resin optical substrate by subjecting the surface of the substrate to low temperature ion bombardment prior to coating in order to open the chemical bonds on the surface of the substrate and coating the substrate surface before the bonds return to their normal or closed condition. The substrate may also be subjected to low temperature ion bombardment during and after coating to further improve coating adherence and abrasion resistance characteristics.

Abstract: The structure of a miniature component for use in connecting optical fibers along with methods for fabricating the component. A small scale tube having precision surfaces inside and out has formed directly in it a converging, preferably plastic, lens capable of imaging a fiber end properly located into assimilarly situated fiber in another like facing component. The outside precision surfaces of the tube serve as references for precision alignment of the component while its inside precision surfaces aid in formation of the lens.

Abstract: Apparatus for coupling radiation into a single-mode core of an optical fiber laser has a single-mode core disposed within a relatively large, multimode cladding at a location which is displaced from the center of the cross-section of the cladding. The cladding is surrounded by a further layer to prevent radiation from propagating out of the cladding. In addition, the apparatus preferably has slight bends to enhance the coupling of radiation from the cladding into the single-mode core. A further embodiment has a single-mode fiber laser disposed in a relatively large, multimode, slab cladding which, in turn, is surrounded by another cladding to prevent radiation from propagating out of the large cladding.

Abstract: A two-element viewfinder comprising a mirror distorted in the form of a generalized polynomial shape, an eye lens, and a Fresnel mirror for use in a reflex camera with a taking objective and a reflex mirror.

Abstract: A system for precisely positioning a printing element relative to a rotating drum, as in a drum printer, employs two position signals for alignment purposes. A pair of linear grids is disposed along a path of travel of the printing element for generating, with the aid of optical beam and sensor devices, a periodic electric signal which varies in accordance with printing element position. One of the grids is stationary and the second of the grids moves with a carriage supporting the printing element. An encoder positioned alongside the drum is operative with a set of markings having a variation in spatial frequency, or a grid overlay, to produce an alternating electric signal which varies in accordance with rotational position of the drum. Motors which rotate the drum as well as a lead screw which translates the printing element may be constructed as synchronous motors to permit phase locking to each other.

Abstract: An improved periscopic viewfinder for use following an afocal zoom section in a still electronic imaging camera. The viewfinder features an infrared detector for sensing scene intensity to provide strobe quenching information, visual displays, and a relay section comprising a symmetrical pair of new achromats for aberration control and field flattening purposes.

Abstract: A fiber optic connector in the form of a two-element relay system which transforms and matches the numerical apertures of an entering beam to that of the acceptance numerical aperture of the exiting optic where in general the numerical apertures can be different. In preferred form, the connector is a pair of spherical balls with their surfaces in contact at a point along an optical axis extending through the centers of the balls. The radii of the spherical balls and their material composition are such that they operate to image fibers or the like one onto the other with their numerical apertures matched when each of the fibers are in optical contact with a respective one of the spherical balls at a point along the optical axis opposite the point of contact. The radii and indices of refraction of the spherical balls can be adjusted to assure that optics with different numerical apertures are optimally coupled.

Abstract: An optical modulator comprises a crystal whose top surface includes a channel waveguide whose axis makes an angle with the crystal optic axis larger than the critical angle for TE-polarized leaky mode propagation. An electrode structure overlies the top surface of the crystal for inducing mode conversion of TM-polarized waves propagating in the waveguide to lossy radiation modes.

Abstract: An M.times.N coupler uses a planar waveguide to couple each of M input channel waveguides to each of N output channel waveguides, the input guides and the output guides being disposed on opposite sides of the planar waveguide. Uniformity of coupling is improved by joining the input channel waveguides to the planar waveguide in a manner to focus the beams emitted by each input guide into the planar waveguide at a common focal point located near the center of the edge where the output guides join the planar waveguide.

Abstract: An optical fiber laser comprising a nearly pure fused silica glass, neodymium doped active core within a cavity in the form of a single mode optical fiber. The gain cavity is end pumped at a nominal wavelength of 0.8 microns and its length and neodymium concentration are adjusted to maximize pump absorption and minimize concentration quenching. Dichroic mirrors are preferably integrally formed on ends of the cavity and have reflection characteristics selected so that the laser has an output at a nominal wavelength of 1.06 microns.

Abstract: A system for the thermal control of optical devices includes an optical device having at least one coating of an electrically conductive material formed on a surface in a heat conducting relationship with the material and connected to a controllable current source which passes varying amounts of electrical current through the layer to vary the amount of thermal energy introduced into the device to control its optical response characteristics. The electrically conductive layer or layers can be optically active, that is, function to affect the light energy transmitted into or through the device as well as acting as an electrically conductive thermal element.

Abstract: An optical fiber laser comprising a gain cavity in the form of a single mode optical fiber with integrally formed dichroic mirror end sections to provide feedback. The fiber core comprises a host material of silicate glass preferably doped with 0.01 to 1 weight percent of just erbium oxide as a lasing medium. The laser is end pumped at approximately 1.49 micrometers with a laser diode, preferably InGaAsP, and has an output at 1.54 micrometers.

Abstract: A TE-TM mode converter utilizes a Y-cut lithium niobate crystal which includes a straight titanium-diffused channel extending along the Z-axis of the crystal. A parallel pair of electrodes lie symmetrically on opposite sides of the channel. a.c. and d.c. voltage supplies are connected to the electrodes to supply voltages so as to effect complete conversion from one direction of polarization to the other direction of polarization of a wave applied as an input to one end of the channel for abstraction at the opposite end.

Abstract: A planar waveguide device including metallic electrodes has a buffer layer of reduced ordinary index of refraction formed in a substrate between its waveguide and electrodes. The device is preferably formed by first fabricating the waveguide in an x-or y-cut substrate of crystalline material, subsequently overcoating the substrate, including the waveguide, with a layer of magnesium, oxidizing the magnesium at temperature to form the buffer layer and then laying the electrodes over the buffer layer. Alternatively, the buffer layer may be formed by a proton exchange process.

Abstract: There is disclosed use of a plasma for consolidating and/or dehydrating a glass soot preform. A plasma is struck in a vessel and the preform is inserted thereinto for effecting treatment of the preform.

Abstract: An optical resonant cavity adapted to receive, as an input from a transmission trunk line, a group of optical signals distributed in wavelength over a predetermined band and to provide, as an output, a narrower band of the optical signals. The wavelength selective nature of the cavity stems from a modification of its resonant modes with periodic structures that are interferometrically formed as alternating layers of high and low index of refraction in photopolymeric material at its opposite ends and operate to suppress resonant modes at wavelengths outside of the narrow band desired as an output.

Abstract: An optical communication system suitable for wide area communications includes a plurality of local networks each having a communications bus and a plurality of terminal devices coupled to the respective local network communications bus for intranetwork communications with other terminal devices within the local network or internetwork communications with terminal devices in other local networks. Each terminal device includes a channel selecting device for selecting one of a plurality of frequency distinct communication channels. Each local network is assigned a common set of communication channels for communications within the local network and also assigned a unique subset of communication channels for internetwork communications. Each local network is coupled to every other local network through a frequency selective coupling means that passes only information signals at frequencies corresponding to the unique subset of communication channels for that local network.

Abstract: An optical physical condition sensor includes an optical fiber resonant cavity into which optical energy, including wavelengths resonatable within the cavity, is introduced. External physical conditions, such as temperature or pressure, change the effective optical path length within the cavity to cause a corresponding change in the cavity's resonant characteristics. Changes in the sensed condition can be determined as a function of changes in the wavelength of optical energy peaks or minimas in the cavity or changes in the cavity's finesse characteristics.