Abstract: The present disclosure describes an optical waveguide device and a method for making such device. The device comprises a substrate; a waveguide embedded in the substrate, the waveguide having a refractive index higher than the refractive index of the substrate; and first and second optical mirrors placed respectively in two different positions along the waveguide. The method comprises steps of (a) cleaning a substrate by means of a cleaning agent; (b) embedding a waveguide in the substrate; and (c) placing first and second optical mirrors respectively at two different positions in the substrate, the steps (b) and (c) being performed in such a manner that the mirrors being positioned along the waveguide.

Abstract: A fused twin biconical taper fiber optic splitter comprised of a pair of non-identical monomode or nominally monomode optical fibers having predetermined cladding diameters fused at respective narrowed waists, the cladding diameter of one fiber before coupler fabrication being greater than the other, whereby wavelength selective coupling between one and the other fiber is obtained.

Abstract: A fused twin biconical taper fiber optic splitter comprised of a pair of non-identical monomode or nominally monomode optical fibers having predetermined cladding diameters fused at respective narrowed waists, the cladding diameter of one fiber before coupler fabrication being greater than the other, whereby wavelength selective coupling between one and the other fiber is obtained.

Abstract: The present disclosure makes a grating assisted optical waveguide device.

Abstract: New types of narrowband wavelength selective optical devices are described. Various configurations are possible, according to the invention, that perform as narrowband wavelength selective transmission or reflection filters or as narrowband wavelength selective optical taps or combiners. The optical devices of the invention include a 3 dB optical directional coupler and wavelength selecting elements such as Bragg reflection gratings or Fabry-Perot resonators usually positioned in optical symmetry with respect to the directional coupler. Two or more wavelength selecting elements can be used to obtain desired filtering characteristics.

Abstract: A method of forming a single mode biconical fiber optic coupler comprising holding 2 or more optical fibers parallel to and in contact with each other at spaced apart locations, exerting equal tension in opposite directions to the fibers at said spaced apart locations to stretch the fibers, fusing the fibers over a waist region, and scanning the tip of a flame from a microtorch back and forth along the fibers at a speed which is at least five times the speed of stretching of the fibers. This results in an overcoupled low loss coupler, a pressure or a temperature sensor, comprised of at least a pair of monomode optical fibers fused and parallel at a stretched waist portion, each having biconical tapers at opposite ends of the waist portion, the coupler having exhibited at least about 500 power transfer cycles during stretching formation of the waist portion.

Abstract: Optoelectronic switching matrix which switches multiplexed input signals to narrowband output lines. Each crosspoint of the matrix is comprised of a heterodyning photosensor, which optically receives the multiplexed input signal and electrically receives a selectable local oscillator signal. The difference frequency can thus be selected to be within the passband of a low pass filter whereby narrowband output signals can be received from the input signals without requiring the use of a demultiplexer.

Abstract: A fiber optic directional coupler comprising a pair of strands of single mode optical fiber having biconical tapers whereby the electromagnetic field within the fibers extend virtually to the cladding outside surface, the strands in the region of the tapers being bent in opposite directions and positioned with their cladding in contact over a length of the waist of the tapers, the cladding in contact being narrowed on one side, flat, and polished, whereby the field is coupled from one strand to the other.

Abstract: An optical coupler for single mode optical signals having a tunable (variable) coupling ratio, and a method of fabricating the coupler. A pair of virtually identical optical fibers are fused together at a narrowed waist region, each fiber being formed of a core and cladding, each being tapered toward the waist in such a manner as to ensure adiabatic propagation of light in the structure. An optical signal carried by one fiber first passes through a decreasing taper region and then passes through an increasing taper region of one or the other fiber (or both). The decreasing taper rate of the input portion of one fiber is such that the optical signal radiates out of the core (where V=1 locally) and into the cladding, as it approaches the waist. The increasing taper rates of the output portions of the two fibers are such that a predetermined coupling ratio is obtained.

Abstract: The optical reflective filter is made from a photosensitive optical fiber having a cladding and a core including germanium. Refractive index perturbations are light induced in the fiber in the region of the guided light. The perturbations can be made to have a constant or a varying periodicity, or a series of constant periodicities. The filters are made from single mode or low order mode fibers having germanium doped silica or germania cores. The center frequency for reflective band or bands has a wavelength in the 400 nm to 550 nm range. The reflective band or bands in the filter can be shifted by stretching the filter.

Abstract: Disclosed are optical data bus configurations for interconnecting terminals so that any terminal can communicate with any other terminal. It is known to do this by connecting terminals serially using two trunk optical fibers and to connect terminals together in a star configuration using a single transmission star or reflection star. The serial network is limited by optical loss while the star network requires more optical fiber and is more costly. Disclosed is a serial bus which uses six fibers arranged in two groups of 3 each, the groups conducting light in mutually opposite directions. A transmitting means in each terminal is coupled to two of the fibers in each group and terminals adjacent any one terminal are connected to a different two fibers than the one terminal. Another arrangement disclosed uses hybrid reflection-transmission star couplers. Terminals can be connected to reflection ports of the hybrid couplers, while the couplers can be interconnected by the transmission ports thereof.

Abstract: The low-loss reflection star coupler has a bundle of multimode optical fibers which is folded on itself and fused over a predetermined length to form a bundle loop. During the fusion process, the fibers are elongated into biconical tapers in the fused section. A hybrid transmission-reflection star includes one or more further fibers having only one biconical tapered section which is fused to the fused section of the fiber bundle.

Abstract: The low loss access coupler includes two multimode optic fibers, each having a biconical taper section. The biconical taper sections of the fibers are fused together to provide optical coupling between the fibers. The fused fibers may also be twisted around one another to enhance mode mixing. The access couplers may be produced by fusing two fibers together along a small length, then heating the fused length and pulling the fibers to form the biconical tapers; or by twisting a portion of each of the fibers around one another, applying a tensile force to the twisted portions of the fibers and heating a region of the twisted fibers to soften and fuse a predetermined length of twisted fibers. If the fibers already have biconical taper sections, the access coupler may be produced by twisting the fibers together along their taper sections and heating a region of the taper sections to fuse them together.

Abstract: A CW Brillouin ring laser utilizing a low loss optical fiber and a pair of partially reflective mirrors positioned to form a ring optical path with the fiber ends, produces a Brillouin shifted Stokes beam when a pump beam is directed into one end of the optical fiber. The Brillouin beam propagates around the ring in a direction opposite to the pump beam. The pump beam is coupled into the ring through one of the partially reflective mirrors and the laser output is the portion of the Brillouin beam passing through the other partially reflective mirror. In the Brillouin laser system, a second pump beam may be directed into the other end of the fiber to produce a second Brillouin beam propagating in a direction opposite to the first Brillouin beam, providing a laser with two distinct Brillouin beam outputs.

Abstract: The coupler consists of an intermediate finite length waveguide located between a first and at least one second waveguide with the refractive index of the intermediate waveguide being greater than the refractive indices of the other waveguides. The intermediate waveguide further includes a structure which either in a fixed manner as by a surface relief, or in a controlled manner--as by electro-optic or acousto-optic perturbation, produces modes of propagation in the intermediate waveguide for a preselected frequency, such that energy may be coupled to or from the waveguides to the intermediate waveguide by mode matching and this energy may be converted from one mode to another in the intermediate waveguide.

Abstract: An optical amplifier particularly for use in a high data-rate fibre-optics communication link utilizing a body of a dielectric substance transparent to signal light of a given band of wavelengths and transparent also to pumping light of a different band of wavelengths, a smooth continuous surface along the length of the body having as amplifying component a layer of laser material adhered contiguous to the surface. Both signal light and pumping light are introduced into an end face of the body, which may be a passive dielectric fibre core such as glass, or a passive dielectric slab with parallel side walls, utilising mode order converting holograms. By the phenomenon of penetration by light of both frequencies within a thin layer of the adhered material as the light beams undergo multiple total internal reflections at the interface between the body and the laser material, atoms of active material, e.g. Nd.sup..sup.