Abstract: An apparatus and method for optical telecommunication includes introducing a laser beam emitted from a light source at a first station into an optical fiber, providing an ultrasonic wave obtained by modulating a voice signal by a signal-applying-device at a work section to the optical fiber, modulating a polarized light passing through the optical fiber in amplitude and frequency, receiving the polarized light with the shifted wave plane at a light-receiving section in a second station, detecting at the light-receiving section in the second station the polarized light which has been modulated by the signal-applying device in the work section, and demodulating the polarized light to obtain a voice signal.

Abstract: An intensity dividing device (10) incorporates a rectangular multimode waveguide (20) connected to an input waveguide (18) and a set of four output waveguides (22). The input waveguide (18) provides a fundamental mode input excitation of CO.sub.2 laser radiation to the multimode waveguide (20). The input waveguide (18) is offset from the multimode waveguide longitudinal axis (24). Consequently, both symmetric and antisymmetric modes of the multimode waveguide (20) are excited. Modal dispersion along the multimode waveguide produces electric field intensity maxima of differing magnitude centred on respective output waveguides (22). This provides division of the input radiation into a range of differing intensity outputs.

Abstract: A first light waveguide is formed, and second and third light waveguides are respectively connected to the first light waveguide at first and second positions. A first coupler for effecting tight branching and/or combining is arranged near the first position, and a second coupler for effecting light branching and/or combining is arranged near the second position. An optical amplifier is arranged on the first light waveguide between the first and second positions for compensating for a light loss of a light wave caused by each of the first and second coupler.

Abstract: An optical waveguide encapsulation for facilitating the tapping of light signals. The optical waveguide includes an optical medium, preferably a polyimide. An encapsulating material comprises a medium which matches the index of the light conducting core of the waveguide. The refractive index of the light conducting core is higher than the refractive index of the encapsulating material, and the encapsulating material is an elastic material.

Abstract: An optical fiber disposed to partially internally reflect optical energy passing therethrough is disclosed herein. The optical fiber 10 of the present invention includes an internal partial mirror disposed to partially transmit and to partially reflect optical energy incident thereon. The internal mirror is effectively realized at an interface I of first and second fiber segments 14 and 18. The first fiber segment 14 includes a first core region 22 which circumscribes a longitudinal axis X. The first core region 22 is of a first cross-sectional area perpendicular to the longitudinal axis X. The inventive fiber 10 further includes a second fiber segment 18 in optical communication with the first fiber segment 14. The second fiber segment 18 includes a second core region 24 which circumscribes the longitudinal axis X, wherein the second core region 24 is of a second cross-sectional area perpendicular thereto.

Abstract: A 1.times.N fiber optic switch is disclosed for selectively coupling light from a first fiber to any one of a plurality of output fibers. The switch includes a coupler in which the first optical fiber and the plurality of optical fibers are elongated in a narrowed coupling region. The coupling region can be bent in various directions to cause the radius of curvature of the input fiber to differ from that of at least one of the output fibers, whereby light propagating in the input fiber can be coupled to only one of the output fibers or to more than one of those fibers.

Abstract: An optical bypass switch includes a normal state and a bypass state, a transmission optical fiber having a signal withdrawn therefrom and injected thereto in its normal state so as to be capable of use in a ring or bus architecture. In the bypass state of the switch, the transmission optical fiber is substantially disengaged so that a signal being transmitted thereby can bypass the switch, and in this state optical fibers connected to a transmitter and a receiver of the bypass switch are maintained in a bent attitude so as to allow signals to be withdrawn and injected thereinto. A loop back path, e.g. a connector optical fiber, is provided which allows a path between the transmitter and the receiver to be completed in the bypass state of the bypass switch, and logic circuitry is provided for analyzing signals detected by the receiver which should have originated from the transmitter for evaluating a state of operation of the transmitter, receiver, and connecting means therefor.

Abstract: A single silica optical fiber (4) is formed in a Sagnac interferometer (2) by forming a fused, dichroic optical fiber coupler (8) having four ports (10, 12, 14 and 16). A 1.3 .mu.m optical data signal is coupled to the port (10) via a dichroic optical fiber coupler (18) which combines it with a 1.53 .mu.m c-w probe signal from laser (16). The coupler (8) splits the 1.53 .mu.m probe signal into two equal intensity, counter-propagating portions and couples the 1.3 .mu.m data signal so it propagates in one direction round the loop (6). The loop (6) exhibits a non-linearity such that the data signal provides a relative phase shift of the counter-propagating c-w probe portions causing a portion of the 1.53 .mu.m signal is switched to port (12). This 1.53 .mu.m switched output provides tapping of the data signal without affecting its intensity.

Abstract: An optical tap comprises a transparent acrylic block (1) having a single V-shaped recess (2) into which an optical fibre (3) is urged by a member (4). The resulting kink in the fibre (3) enables light to couple between the core of the fibre and the block (1) from what is substantially a point source defined by a tight curve of short arcuate length at the kink.

Abstract: A continuously variable fiber optic attenuator 10, particularly for attenuating single mode fibers, has means 20 for supporting a section 25 of an optical fiber 24 substantially along the length of the section 25 and means 22 for bending at least a portion of the supported optical fiber section 25 in a controlled manner for attenuating light passing through the optical fiber 24. Preferably, the support means 20 comprises a deformable support means such as a spring 15 or an elastomeric body 71 for supporting the optical fiber 24 as it is bent. Most preferably, the deformable support means supports a section 25 of optical fiber 24 formed in one or more loops around the deformable support means, and the bending means is a plunger 22 movable to an extended position pressing against the support means 20 to bend portions of the loops of optical fiber 24 in a controlled manner.

Abstract: A splitter is produced by ion diffusion in a glass substrate and it is designed to assure the transmission of an optical signal toward two outputs with a predetermined ratio of the signal power appearing at these 2 outputs. In accordance with the invention, it comprises an X-junction of two rectilinear waveguides defining at their intersection a half-angle .alpha., the angle and the geometry of the central region being chosen in such a way as to establish the predetermined power ratio and the relative achromaticity of the device.

Abstract: In accordance with the invention an integrated optic device useful as a low level polarization independent optical tap comprises a pair of optical waveguides intersecting at an angle of 10.degree.-25.degree. to provide a tap signal in the range minus 20 dB to minus 60 dB. In a preferred embodiment for use in a passive repeater for undersea cable, the device comprises fiber-matching waveguides of phosphorus silicate glass on an oxide covered silicon substrate with a boron and phosphorus silicate cladding. The waveguides preferably intersect at an angle of 13.degree.-16.degree.. The preferred repeater further comprises a 3 dB coupler for averaging the power provided by two external pumping sources and a pair of wavelength division multiplexers for applying the pumping power to the outputs of the tap.

Abstract: An achromatic fiber optic coupler of the type wherein a plurality of single-mode optical fibers, each having a core and a cladding, are fused together along a portion of the lengths thereof to form a coupling region. The propagation constants of the fibers are preferably equal; however if the fiber claddings have different refractive indices, the lowest cladding refractive index is n.sub.2. A matrix glass body of refractive index n.sub.3 surrounds the coupling region, n.sub.3 being lower than n.sub.2 by such an amount that the value of .DELTA..sub.2-3 is less than 0.125%, wherein .DELTA..sub.2-3 equals (n.sub.2.sup.2- n.sub.3.sup.2)2n.sub.2.sup.2.

Abstract: An optoelectronic device having an optical guide and photodetector integrated on a common substrate is provided with a light coupling means for increasing the absorption of light within the photodetector. This means consists of freeing the lower portion of the guide layer--opposite the photodetector--to bring it into contact with air. The use of air has the effect of repelling the light propagating through the guide layer towards the absorbent layer of the photodetector thereby increasing the photodetector efficiency.

Abstract: A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

Abstract: An optical device includes a channel or three-dimensional light waveguide for propagating a light wave therethrough and an optical coupler for effecting at least one of branching and combining of the light wave by splitting a wavefront of a field distribution of the light wave. The coupler is produced by forming a portion whose reflection factor is different from the waveguide, extending in a vertical direction of the waveguide. The portion of different reflection factor is formed deep enough in the vertical direction to perform the splitting of the wavefront of the field distribution of the light wave with respect to at least a horizontal or lateral direction, or the portion of different reflection factor is formed at a flat portion of the waveguide.

Abstract: An optical tapping coupler for a cable including at least one optical conductor (1) constituted by a step-index glass fiber which is covered by a plastic covering. First means (3 & 4, 5 & 6, 7, 8, 12) enable a determined position and a determined curvature to be given to a portion of each optical conductor of the cable, with each optical conductor being dissociated from the rest of the cable at the tapping location. Second means (21, 22) enable one end of each auxiliary optical conductor (30) to be mechanically brought against a respective cable optical conductor, with a small angle of incidence, in the region in which the cable conductor presents the determined curvature. Optical-index-matching third means are provided between the end of each auxiliary optical conductor and the cable optical conductor against which the end is positioned. The invention is used in particular for multi-station local network buses.

Abstract: In an optical connection device for use in responding to an incident light beam to produce a plurality of output light beams, the incident light beam is incident onto a planar substrate on which a plurality of optical islands which have refraction coefficients different from the planar substrate. The incident light beam travels as an internal light beam within the planar substrate with reflections repeated in the planar substrate and is emitted as output light beams through the optical islands when the internal light beam arrives at the optical islands. Thus, the incident light beam is distributed through the optical islands outside of the planar substrate. If each of optical nodes is located in vicinity of the optical islands and generates the input light beam and receives each of the output light beams, bidirectional communication can be carried out through the planar substrate and the optical islands among the optical nodes.

Abstract: Tapered two-mode optic fibers are used as sensors with sensitivity varying as a function of length. The optical fiber sensors act as vibrational-mode filters thereby performing initial signal processing of the sensor signal. The sensors are based on the differential propagation constant in a two-mode fiber that is directly dependent on the normalized frequency or V-number. Tapering the fiber changes the V-number and hence can change the sensitivity of the sensor along its length. By choosing an appropriate weighting function in the manufacture of the sensor, it is possible to implement vibrational-mode analysis, vibrational-mode filtering and other functions that are critical in control system applications.

Abstract: A measuring device for measuring light travelling through an optical medium with the device including two independent components, with each independent component including one transmitter and one receiver. Each of the components are connected via a flexible lead to a measuring and evaluation section of the measuring device in which an evaluation and/or display of the measuring signal obtained by the components will be produced.

Abstract: An optical communications network in which optical signals from a transmitter (T) are distributed to receivers (R.sub.i) via an optical waveguide (2) and couplers (C.sub.i) are amplified as they propagate along the waveguide (2). The amplifiers A.sub.i are all pumped by a single optical pump source (4) coupled to the optical fibre (2) by a dichroic coupler (6). By using the optical waveguide (2) to distribute the pump power to the amplifiers A.sub.i multiple optical pump sources are avoided.

Abstract: A means of fabricating wideband 1.times.8 singlemode fiber optic couplers is disclosed. It has been found that a 1.times.7 fiber optic coupler can be fused by twisting six fibers around a central seventh fiber, heating the region on contact among the seven fibers, and drawing until the desired distribution of optical power is achieved among the seven fibers. Both 1.times.6 and 1.times.7 couplers can be made this way depending upon the extent of drawing. Using such a coupler in combination with conventional 1.times.2 and wideband 1.times.2 couplers allows fabrication of 1.times.8 couplers using only two or three separate couplers compared to seven couplers required in coupler tree structures. Further, by taking advantage of selected wavelength response behaviors characteristic of each coupler in the combination, the combination of 1.times.2 and 1.times.7 or 1.times.6 couplers is done in a manner to provide relatively improved coupling uniformity over a bandwidth of .+-.

Abstract: An optical fiber connector or coupler (24-54) is provided which partially reflects light travelling in one direction (56) but preferably transmits light without reflection in the opposite direction (58). When such connectors (C.sub.o to C.sub.n) are alternated with ambient environment sensors (S.sub.l to S.sub.n) in an optical fiber transmission path, light pulses launched in the one direction from a source (60) produce reflected light at a detector (62) which reflected light can be correlated to a preselected characteristic of the environment at each sensor. A series of such connectors can be used without sensors to provide reference signals from points along an optical fiber transmission path. A single fiber path can be used, without the need for a separate fiber for feedback.

Abstract: A light-waveguide device has a light waveguide having a circumference provided with a groove, and a coupling element having a carrier and at least one of a light-sensitive transmitting component and a light-sensitive receiving component for coupling an optical radiation in and out of the light waveguide. The carrier is T-shaped and has a base surface and a central support. The at least one light-sensitive component is arranged on the T-shaped carrier and forms with the base surface of the T-shaped carrier an angle .alpha..

Abstract: An optical fibre communication network comprising one optical source (1) connected to one end of an optical fibre (3), and several optical receivers (9) for detecting light scattered to the side of the optical fibre (3), the network being characterized by the fact that each optical receiver (9) is sufficiently sensitive to require for reliable communication only light lost by the fundamental scattering of the fibre (3) during normal propagation of the light originating in said optical source (1) while travelling in the vicinity of the optical receiver (9).

Abstract: A sender/receiver apparatus configured for a bi-directional beam wave guide may be configured with an optical prism. the device can be placed in a housing with a wave guide socket connected at an optical port. Spherical lenses and an internal wave guide may be located between the prism and the optical port, the sender and the receiver, respectively. The prism may exhibit an aperture reflecting surface or diaphragm.

Abstract: The coupler includes a waist region formed by merging and fusing a plurality of optical fibers with the waist region encapsulated in photorefractive encapsulating material. The index of refraction of the encapsulating material is modulated by applying illumination thereto, so as to vary the coupler output ratio. The applied illumination can direct the coupler output from one output fiber to another output fiber thereby providing an optically actuated switch. The illumination applied to the encapsulating material can direct a large optical power signal applied to an input fiber from one output fiber to another output fiber thereby providing an optical amplifier analogous to a transistor. One of the output fibers of the element can be utilized to provide the encapsulating material illumination thereby providing an optical feedback oscillator.

Abstract: Fiber optic power splitters having a central fiber and a selected number of surrounding fibers spaced periodically around the central fiber and the method of fabricating such splitters are described. For splitters having between three and five surrounding fibers, the central fiber is made to have a reduced diameter relative to the surrounding fibers so that it contacts each of the surrounding fibers and each of the surrounding fibers, likewise, touches each of its neighboring fibers. For splitters having seven or more surrounding fibers, the diameters of the surrounding fibers are reduced relative to the central fiber so that mutual contact is made among the set of equal diameter surrounding fibers and the central fiber. The equation governing the relative diameters of the central and surrounding fibers, and methods of obtaining uniform diameter reduction in an optical fiber are described.

Abstract: A device for recognizing useful signals, transmitted over a distance and comprising noisy electromagnetic, light signals containing information. A tapped delay line is used for this purpose, whereby a waveguide is manufactured in a spiral groove of a wafer using microtechnology, in order to form a planar light waveguide coil on a chip.

Abstract: An optical divider for multimode optical fibers of graded-index (GI) type composed of an optical input section for securing input optical fiber, a branching section including an optical waveguide having rectangular sectional shapes irrespective of a kind of material or a method of fabricating the same and consists of a main optical waveguide and branch waveguide, and an optical output section for securing an array of output optical fibers, wherein the main optical waveguide having a width D and a length M is divided contiguously into N branch optical waveguides, preferably three or more having uniform width W, the optical waveguide having substantially uniform core thickness T is specifically related with the core diameter K of the otpical fiber to fufull the following relational formulas:0.7.ltoreq.T/K.ltoreq.0.85 (1)0.35.ltoreq.W/K.ltoreq.0.80 (2)15.ltoreq.M/D.ltoreq.70 (3)D=N.times.

Abstract: An interferometric fibre optic network includes a downlead optical fibre (12) and a pair of uplead optical fibres (14, 16). Sites for a plurality of interferometric sensor pairs (25) are arranged whereby each pair (25) is optically connected in use of the network to the downlead and uplead fibers (12, 14, 16) via a 3.times.3 fibre optic coupler (30) and respective further fibre optic couplers (32) on the uplead fibres (14, 16). The uplead fibres (14, 16) are multimode optical fibres, and each of the 3.times.3 couplers (30) is optically connected to the respective further couplers (32) by a single mode optical fibre (34). The further couplers (32) are asymmetric couplers having high tap-on coupling from the single mode optical fibre (34) to the respective uplead fibre (14, 16) but low tap-off coupling from the uplead fibre (14, 16).

Abstract: A main optical waveguide portion and/or branching optical waveguide portions of the optical waveguide is tapered in such a way so as to expand towards the output side for reducing a coupling loss due to mismatching of numerical apertures N.A. between optical fibers and the optical waveguide, wherein the light entering the optical waveguide at an angle determined by the numerical aperture N.A. of the optical fiber gradually reduces its angle of incidence to an interface of the core and cladding as it passes by a portion where the taper is provided and when the light reaches the output side of the optical fiber, the numerical aperture N.A. thereof is effectively reduced to a value which is lower than the numerical aperture N.A. determined by a difference of refractive-indices in the optical waveguide. By making the numerical aperture N.A.

Abstract: An optical fiber coupler for coupling a high power laser beam delivered by an incoming fiber into multiple outgoing fibers is disclosed. The beam emitted from the incoming fiber is collimated and split into multiple split beam portions for injection into the respective multiple outgoing fibers. Each split beam portion is shaped for injection into its respective outgoing fiber in accordance with specific beam injection criteria.

Abstract: A network for distributing a set of independent high-frequency electrical signals comprises an optical rail waveguide that is fed with a measured amount of optical power from a single source, and a set of optical railtaps positioned at sequential locations along the optical rail waveguide. Each optical railtap functions to extract a corresponding specified fraction of the measured amount of optical power from the optical rail waveguide when a corresponding one of the independent electrical signals is applied thereto. The fractions of the measured amount of optical power extracted from the optical rail waveguide at the corresponding sequential locations along the optical rail waveguide constitute a set of independent high-frequency optical signals, which correspond to the independent high-frequency electrical signals.

Abstract: An optical fiber tap or coupler in which optical energy is extracted from or coupled into an optical fiber via a bent section of the fiber and in which compression means is provided for applying a compression force along the fiber including along at least the radially outermost portion of the bent section to reduce the likelihood of fracture.

Abstract: A tap for coupling light from an intermediate portion of an optical fiber core and a light element by passing light through a side of the optical fiber includes an optical coupler in contact with an outside surface of an optical fiber which is bent and disposed in a plane. A light reflector extending transverse to the plane deflects the withdrawn light towards the end surface of a light element disposed completely outside the plane. The tap may be used as a read tap to withdraw light, or as a write tap to inject light in optical fiber networks. A spring biased closure member urges the optical fiber to maintained in bent registration with the optical coupler within the plane. Simple tools and general craft training and knowledge may be applied to insert into, and remove the optical fiber from, the tap.