Abstract: The present invention is directed to Y-branch digital optical switching and optical attenuator devices, which enhance the security of optical communications channels in the event of an electrical power loss.

Abstract: An optical power splitter that can minimize the chip size with its manufacturing cost. The optical power splitter has one input optical waveguide and N output optical waveguides and splits an optical signal incident from the input optical waveguide into N optical signals. The optical power splitter includes at least two optical splitters having a structure of a planar lightwave circuit element and arranged apart from one another at predetermined intervals in a single chip, and an alignment waveguide for aligning the input and output optical waveguides of the plurality of optical splitters.

Abstract: An optical splitter includes a main waveguide, a tapered waveguide, and a split waveguide group having first and second split waveguides. The side portions of the tapered waveguide taper and expand from a first end portion toward second end portions. The widths of the split waveguides differ from each other. The whole width of the split waveguide group at connecting portions between the tapered waveguide and the split waveguides is smaller than the width of the tapered waveguide at the second end portions. Step portions are formed between the split waveguide group and the side portions.

Abstract: A channel waveguide switch, driven by liquid crystal thermo-optic elements, suitable for use in integrated optic applications. Two trenches, one on either side and parallel with the core region of a channel waveguide Y-branch, are filled with a liquid crystal material possessing positive birefringence. When a given trench is held at a temperature a few degrees below the clearing point, the liquid crystal is in its nematic phase with its director aligned along the long direction of the trench so that both polarizations of the guided mode are loaded by the liquid crystal's ordinary refractive index. When the trench is held at a temperature a few degrees above the clearing point, both polarizations of the optical mode are loaded by the liquid crystal's isotropic index. By holding the temperature of the second trench at the alternate temperature, the differential loading on the Y-branch causes the guided mode to be switched into the path loaded by the liquid crystal's isotropic index.

Abstract: The present invention relates a method for manufacturing an optical coupler/splitter. A Y-shaped waveguide core is formed by focusing a laser beam into a cladding layer that is formed from a glass material. At least one portion of this Y-shaped waveguide core other than the input port and the output ports is treated as a refractive index adjustment area. After the portions of the Y-shaped waveguide core other than the refractive index adjustment area have been formed by focusing a laser beam, signal light is inputted into the input port of the Y-shaped waveguide core and the signal light outputted from the output ports of the Y-shaped waveguide core are monitored. The refractive index of the refractive index adjustment area is determined based on the result of the monitoring and is adjusted by focusing a laser beam repeatedly.

Abstract: Apparatus for optically pumping a clad amplifier fiber includes one or more transmission fibers arranged and configured to insert pump-light from a pump light source such as a diode-laser into the cladding of the amplifier fiber. The pump light propagates through the cladding and a portion of the pump light is absorbed in the doped core of the amplifier fiber. At least one of the transmission fibers is arranged to receive an unabsorbed portion of the propagated pump light from the amplifier cladding and re-insert the unabsorbed portion of the pump-light into the cladding for re-propagation through the cladding. This provides that pump light that would otherwise be wasted is circulated through the amplifier fiber for further absorption by the amplifier core.

Abstract: This two input two output type optical switch includes four one input two output type optical switches which are arranged to oppose one another, each of these one input two output type optical switches including a Y branch portion in which one optical waveguide is branched into two optical waveguides. And two refractive index adjustment means are provided in the vicinity of each Y branch portion. Switching over of the optical path is performed by half of the refractive index adjustment means functioning alternately. Moreover, a light output intensity variable attenuation function which attenuates by any desired amount the intensity of the light which is being outputted is implemented, at some input port and/or output port, by operating at least one of the refractive index adjustment means which is not currently being used for switching over of the optical path.

Abstract: An optical coupler is provided. It has a bundle of multimode fibers with a few-mode fiber in its centre. Such bundle is fused at one end which is the output end for the signal that is transmitted by the few-mode fiber. To make the coupler, this output end of the bundle is aligned and spliced with a large area core double clad fiber while preserving the modal content of the feed-through. A method for making such optical coupler is also provided. It includes the steps of bundling a central few-mode fiber with a plurality of multimode fibers and then fusing one end of such bundle and aligning it and splicing with a large core double clad fiber, while preserving fundamental mode transmission from one to the other.

Abstract: A multimode interference device and method of making the same comprises at least one input port, at least one output port, a multimode interference region separating the input port from the output port, and at least one subregion in the multimode interference region, wherein a self-image length within the multimode interference region is reduced by a factor that is approximately equal to one plus a number of subregions configured in the multimode interference region, wherein the at least one subregion is configured to have an effective width and effective refractive index running longitudinally through the multimode interference region. Additionally, the subregion may comprise at least one slot.

Abstract: An apparatus and method for splitting a received optical signal into its orthogonal polarizations and sending the two polarizations on separate dual integrated waveguides to other systems on chip for further signal processing. The present invention provides an apparatus and method for facilitating the processing of optical signals in planar waveguides received from optical fibers.

Abstract: The invention provides a wavelength division demultiplexing apparatus which can reduce the connection loss between an input slab and channel waveguides and can suppress excitation of higher-order mode light to reduce the loss. The apparatus includes a first waveguide for propagating WDM light, a first slab for diffusing the light from the first waveguide, a plurality of channel waveguides having a series of different waveguide lengths with a predetermined difference for receiving and splitting the light from the first slab, a second slab for condensing the split light from the channel waveguides, and a second waveguide for propagating the light from the second slab therein, all formed on asubtrate. The channel waveguides and the first slab are optically connected to each other at a number of nodes greater than the number of nodes at which the channel waveguides and the second slab are connected to each other.

Abstract: An apparatus and method for combining light signals carried on a plurality of input fibers onto a single receiving fiber with a high degree of efficiency. The apparatus broadly comprises the receiving fiber and a plurality of input fiber-lens assemblies, with each fiber lens assembly including an input fiber; a collimating lens interposed between the input fiber and the receiving fiber and adapted to collimate the light signal; and a focusing lens interposed between the collimating lens and the receiving fiber and adapted to focus the collimated light signal onto the face of the receiving fiber. The components of each fiber-lens assembly are oriented along an optic axis that is inclined relative to the receiving fiber, with the inclination angle depending at least in part on the input fiber's numerical aperture and the focal lengths and diameters of the collimating and focusing lenses.

Abstract: A method and apparatus for splitting/coupling optical signal(s). A unitary waveguide section having a first lateral dimension perpendicular to a propagation axis of the unitary section is provided. An offset waveguide section is optically coupled to the unitary waveguide section. The offset waveguide section has a second lateral dimension approximately equal to twice the first lateral dimension. Two branching waveguide sections having first ends are optically coupled to the offset section at the first ends.

Abstract: A planar light wave circuit is disclosed, which comprises: a first waveguide for receiving optical signals from an outside; a second waveguide having a first end surface and a second end surface, so that lights outputted from the first waveguide are partially reflected by the first end surface and are partially incidented into the first end surface and then outputted through the second end surface; a third waveguide for receiving the light reflected by the first end surface; and a common region bordering each end surface of the first to the third waveguides and having an index of refraction different from an index of refraction of the second waveguide.

Abstract: The integrated-optics coupling component is designed to cooperate with a transverse multimode power laser diode (2) with semi-conductor to form a transverse multimode power laser. It comprises an input zone (4) connected to at least one output waveguide (6) by at least two adiabatic tapering zones (5). At least two filtering windows (7) form the inputs of the adiabatic tapering zones (5) at the end of a diffraction zone defined by the input zone. Reflecting elements, for example a Bragg grating (12), can be arranged on the output waveguide. An emitting face (3) being antiglare-treated, an extended laser cavity oscillating on a single predetermined mode is thus defined between a reflecting rear face (11) of the laser diode and the reflecting elements (12).

Abstract: Substantially S-shaped optical waveguides are embedded in a semiconductor substrate, and at least two optical waveguide returning parts are interposed between the input and output ends of the waveguides. Each of the optical waveguide returning parts includes a multiplexing portion. A reflecting part is located on a rear end side of the multiplexing portion of each optical waveguide returning part. Thus, the length between input and output ends of the waveguides can be reduced, suppressing bending loss, and achieving a high speed and small size integrated optical device.

Abstract: A signal may be split by a splitter into a plurality of output signals. Each of these output signals may then be amplified. Amplified spontaneous emission noise may be removed using a tunable filter for each of the signal outputs. As a result, an output signal may be provided with greater power so that, in some embodiments, a single split signal may be utilized to service more end users.

Abstract: A tapered waveguide improves insertion loss occurring at the slab/waveguide interface of an optical array waveguide grating (AWG). The tapered waveguide has two segments. The first segment decreases from a first thickness, nearest the slab of the AWG to a second thickness moving away from the slab. The second segment has a substantially constant or uniform thickness equal to the second thickness of the first segment. The second segment may also have a swallowtail shape comprising a forked end having two sidewalls tapered back towards the first segment. Light that would otherwise be lost at the slab/waveguide interface is instead captured by the tapered waveguide which laterally channels the light back into the waveguides thus mitigating insertion loss.

Abstract: Optical structures useful in splitters, couplers, combiners, and switches are provided. An example optical structure has a Y-branch configuration that includes a linear taper segment and two branching waveguides. A straight section extends between the linear taper segment and the two branching waveguides to reduce losses during splitting/combining operation. The straight section may be used in Y-branch configurations having a blunt section, as well as configurations without a blunt section. Straight sections formed of a single segment and of multiple segments are shown, and the straight sections may be formed of substantially parallel outer walls or fanning-out outer walls. Further, in some embodiments, the branching waveguides form acute angles at the boundaries with the straight segment.

Abstract: An optical network, in the form of a 1×2N splitter, includes a series of interconnected distribution devices of varying size. Each distribution device may be an H-tree distribution device having an input waveguide and four output waveguides that provide in-phase, equal intensity copies of a signal received on the input waveguide. The network may include a primary H-tree distribution device and a plurality of secondary H-tree distribution devices each of a smaller size than the primary H-tree distribution device. Individual H-tree distribution devices may have a first stage Y-branch and a second stage Y-branch each of different radii of curvature. Further still, progressively smaller radius of curvature Y-branches may be used to form the 1×2N splitter, where N may be an even or odd integer.

Abstract: An optical power splitter is provided that can stably operate even when there is a mode mismatch between an input optical signal and the optical power splitter. The optical power splitter of the present invention includes a semiconductor substrate, an optical waveguide stacked on the semiconductor substrate, and a clad surrounding the optical waveguide.

Abstract: An optical device consisting of a core layer, a first clad layer in contact with the core layer, a second clad layer, third clad layer and at least one electrode for applying a certain voltage or supplying a certain current. The second clad layer is deposited on the third clad layer and the core layer is provided between the first clad layer and the second clad layer. The core layer, first clad layer, second clad layer and third clad layer consist of a material with a negative refractive index variation coefficient, and the third clad layer has a refractive index smaller than that of the second clad layer.

Abstract: An achromatic power splitter is formed from multiple optical fibers. The achromatic power splitter operates single mode, which permits the power splitter to operate substantially insensitive to changes in wavelength of the input light, to changes in the polarization of the input light, to changes in the temperature of the device, and to exposure to ionizing radiation.

Abstract: An apparatus and method for splitting and combining optical beams with reduced contact loss and electrical isolation. In one embodiment, an apparatus according to embodiments of the present invention includes a first optical waveguide section disposed in semiconductor material. The apparatus further includes second and third optical waveguide sections symmetrically disposed in the semiconductor material proximate to an end of the first optical waveguide section. First and second insulating gap regions are disposed in the semiconductor material between the first and second optical waveguide sections and the first and third optical waveguide sections, respectively, such that there is a first evanescent coupling between first and second optical waveguide sections across the first insulating gap region and there is a second evanescent coupling between the first and third optical waveguide sections across the second insulating gap region. The first, second, and third waveguide sections are electrically isolated.

Abstract: In a bi-directional optical transceiver module, a first waveguide transmits a optical signal received from a light source to a high reflection layer formed on a waveguide substrate. A second waveguide extends from the optical fiber to the high reflection layer. With a first mode coupling region formed by ends of the first and second waveguides near the high reflection layer, the second waveguide transmits the transmission optical signal mode-coupled from the first waveguide to the optical fiber and receives the reception optical signal from the optical fiber. A third waveguide extends from the optical detector to near an end of the optical fiber. With a second mode coupling region formed by an end of the third waveguide and the other end of the second waveguide, the third waveguide transmits the reception optical signal mode-coupled from the second waveguide to the optical detector.

Abstract: An optical pump device including a pump source optically connected to an optical divider including one input channel and n output channels. The input channel is configured to receive a pump wave derived from the source and the n output channels are configured to output n pump waves, where n is an integer greater than 1. The pump device can be used in an optical amplification device. The device has applications in all domains in which several optical pumps are necessary, and more particularly in the domain of optical telecommunications, and for example for optical amplifiers.

Abstract: The dual wavelength semiconductor laser source for an optical pickup includes: two semiconductor laser elements outputting laser beams having oscillating wavelengths different from each other; and a multiplexing waveguide, formed inside of a photonic crystal having a photonic band gap, having one output end outputting laser light at one end surface and two input ends at the other end surfaces. Output beams of the two semiconductor laser elements are coupled to the respective two input ends of the multiplexing waveguide and the two beams are outputted from the one output end of the multiplexing waveguide.

Abstract: A Y-branched optical waveguide with a uniform output characteristic for use in optical communication systems is disclosed. The optical waveguide, consisting of a core section serving as a transmission medium of an optical signal and a cladding section surrounding the core section, is formed on a semiconductor substrate. An input-tapered waveguide is configured to receive the optical signal through a first ending section and to output the optical signal through a second ending section, with a symmetrical structure with respect to a centered line of the input-tapered waveguide, so that a width of the input-tapered waveguide extends more widely along the centered line.

Abstract: A system for processing an optical signal into a plurality of optical output signals includes a laser for generating an optical signal along an optical signal path. An optical splitter receives the optical signal and includes an input optical fiber and a stepped, optical splitter circuit formed from a plurality of laser ion doped optical waveguides branching into a plurality of output optical signals. An optical pump source pumps an optical pump signal through the stepped, optical splitter circuit and excites the erbium to distribute gain throughout the optical splitter.

Abstract: Disclosed is an optical power splitter that maximizes uniformity of the power split ratio, while minimizing the output differences between channels. The optical power splitter includes a semiconductor substrate; a core layered on the semiconductor substrate, functioning as a transmission medium for optical signals composed of multi-channels according to a wavelength, wherein the core comprises an input waveguide for receiving the optical signals and a plurality of output waveguides for outputting respective portions of the optical signals whose powers are split; a clad for encompassing the core; and a rectilinear assistant waveguide coupled between the input waveguide and a plurality of output waveguides, having a designated width and length to uniformize mode profiles of the multi-channels that are manifested on the output side edge of the rectilinear assistant waveguide.

Abstract: A method and system for adjusting power at output ports of a wavelength division multiplexing (WDM) coupler. A loss element may be placed at one or more of the output ports of the WDM coupler. The loss element may have a filter characteristic that matches the temperature sensitivity coefficient of the WDM coupler. The filter characteristic may reject power at one of the two output ports as a function of temperature. As a result, the loss element may balance the power at the output ports of the WDM coupler despite temperature variations.

Abstract: The present invention provides a fiber Bragg grating sensor system, which comprises a light-division device having receiving-sending terminals and sensing terminals, a light generating device and a photo detector coupled with receiving-sending terminal of a light-division device, sensing fibers coupled with the sensing terminals, said sensing fiber comprising a fiber Bragg grating, a information processor connecting with said photo detector. The light-division device distribute different optical energy ratio from said receiving-sending terminals to said sensing terminals. The intensity and wavelength division multiplexing can make different intensity for the information addressed of different sensing fiber on the same optical channel to enhance the sensing capacity of fiber Bragg grating sensor system.

Abstract: An optical network is formed of multiple H-tree distribution devices, separated into different waveguide layers. The optical network receives an input optical signal, such as an optical clock signal, and makes duplicate copies of that input signal. The duplicate copies are routed through the connected H-tree distribution devices, which are arranged to produce identical, synchronized copies of the clock signal. The network can take the form of a 1×2N device, where 2N represents the number of these output signals. The H-tree distribution devices forming the network are of varying size and may be formed in different waveguide layers with different index of refraction differentials between the H-tree devices and surrounding claddings. In some forms, the optical network is integrated with optical-to-electrical converters, i.e., photodetectors, which take the optical output signals and convert them to synchronized electrical signals that may be communicated to digital circuits.

Abstract: A wavelength-multiplexing connector and a transmitting/receiving part can be easily connected to and disconnected from each other. The wavelength-multiplexing connector comprises a single optical fiber, through which a plurality of optical signals having different wavelengths are transmitted, and a wavelength-multiplexer optically coupled to the optical fiber and capable of optically separating an optical signal having a particular wavelength out of the plurality of optical signals. The wavelength-multiplexer comprises a wavelength division multiplexing filter disposed at a midway of a first light waveguide, and a multilayered film mirror for reflecting, at a midway of a second light waveguide, a signal separated by the wavelength division multiplexing filter.

Abstract: Optical apparatus and optical switching methods that provide optical high data rate switching at a wavelength or packet level using optical tone addressing. Optical signal routing is a result of optically induced total internal reflection at the intersection of an X-junction waveguide structure. The total internal reflection effect is controlled by a high intensity optical pump beam separate from the optical data signal. Total internal reflection may result from a free-carrier induced change in refractive index, which is a nonlinear effect found in common III-V semiconductors and selected polymers. Optical switching networks may be formed using cascaded pluralities of optical waveguide switches.

Abstract: The optical branching device includes an input optical waveguide for outputting light inputted from a light input end face to a light output end face, a tapered optical waveguide having one end face connected to the light output end face and a width expanding at a predetermined angle, and branching optical waveguides connected to the other end face of the tapered optical waveguide at a predetermined branching angle, in which when a propagation constant of a leaky mode is ?L, a propagation constant of a fundamental mode is ?0, a meander period is ?, and ?=2?/(?0-?L), an optical waveguide length L from a position which becomes a cause of the leaky mode to the light output end face is substantially integer times ?/2.

Abstract: The present invention relates to a semiconductor optical tap comprising: a multimode interferometer (MMI) (6); an input waveguide (1) coupled to the MMI; a first output waveguide (2) coupled to the MMI; and a second output waveguide (3) coupled to the MMI. The first and second output waveguides (2,3) overlap (d) such that unequal portions of light are coupled from the MMI into the first and second output waveguides (2,3). The input waveguide (1) and the first and second output waveguides (2,3) may have a rib structure. They may also be adiabatically tapered waveguides. The first and second output waveguides (2,3) may have different starting widths.

Abstract: The invention relates to an optical branching circuit connected to a light output end face of an optical waveguide circuit or an optical branching circuit and for branching input light, and has a feature to provide an optical branching circuit with less branching ratio variation. The optical branching circuit is comprised of an input optical waveguide formed on a silica glass substrate and for outputting input light inputted from a light input end face to a light output end face, a tapered optical waveguide disposed to be shifted with respect to the input optical waveguide at the light output end face, and branching optical waveguides connected to a light output end face of the tapered optical waveguide at a predetermined branching angle.

Abstract: The invention provides a planar lightwave circuit type variable optical attenuator in which a small PDL is maintained even when an attenuation is large. The variable optical attenuator is constituted by a Mach-Zehnder interferometer comprising a substrate, two optical waveguide arms buried in a clad formed on the substrate, and thin-film heaters disposed on the surface of the clad and adjusting optical lengths of the optical waveguide arms. The optical waveguide arms are each made of a silica-based glass material, and a difference &Dgr;L0 between arm lengths is set to be in the range of 0.38 &mgr;m to 0.52 &mgr;m.

Abstract: An apparatus and method for splitting and combining optical beams with reduced contact loss and electrical isolation. In one embodiment, an apparatus according to embodiments of the present invention includes a first optical waveguide section disposed in semiconductor material. The apparatus further includes second and third optical waveguide sections symmetrically disposed in the semiconductor material proximate to an end of the first optical waveguide section. First and second insulating gap regions are disposed in the semiconductor material between the first and second optical waveguide sections and the first and third optical waveguide sections, respectively, such that there is a first evanescent coupling between first and second optical waveguide sections across the first insulating gap region and there is a second evanescent coupling between the first and third optical waveguide sections across the second insulating gap region. The first, second, and third waveguide sections arc electrically isolated.

Abstract: Disclosed is a multiple split optical waveguide in which a branch waveguide path at an output end of a branch part of a first stage defines an acute angle with respect to an input waveguide path, and a branch waveguide path at an input end of a branch part of an n-th stage is no more inclined toward a central axial line defined by an extension line of the input waveguide path than a branch waveguide path at an input end of a branch part of an (n+1)-th stage, n being an integer equal to or greater than two. Thus, the waveguide paths are prevented from spreading beyond the first branch angle, and it becomes easier to bring the outer waveguide guide paths back toward the center. This prevents an increase in the variations in length between the outer and inner waveguide paths.

Abstract: The invention provides a wavelength division demultiplexing apparatus which can reduce the connection loss between an input slab and channel waveguides and can suppress excitation of higher-order mode light to reduce the loss. The apparatus includes a first waveguide for propagating WDM light, a first slab for diffusing the light from the first waveguide, a plurality of channel waveguides having a series of different waveguide lengths with a predetermined difference for receiving and splitting the light from the first slab, a second slab for condensing the split light from the channel waveguides, and a second waveguide for propagating the light from the second slab therein, all formed on a subtrate. The channel waveguides and the first slab are optically connected to each other at a number of nodes greater than the number of nodes at which the channel waveguides and the second slab are connected to each other.

Abstract: An optical data throughput protection switch is provided which provides access to a data-carrying first optical path in a manner which protects the data from interference from equipment utilizing said access, and eliminates optical connectors along the first optical path. The protection switch includes a controlling means and a controllable switch which is optically coupled to the first optical path the termination of a second optical path. The controllable switch is controlled by the controlling means and functions to enable and disable optical coupling between the termination, of the second optical path and the first optical path. This may be effected in a manner that allows access to the first optical path when there is no data traffic thereon, and denies access thereto when data is present, resulting in data throughput on the first optical path being protected from signals of the second optical path.

Abstract: An optical interleaving switching method and apparatus. In one aspect of the present invention, the disclosed apparatus includes first and second multi-mode interference (MMI) coupling devices disposed in a semiconductor substrate. Each of the first and second MMI coupling devices include first and second inputs and first and second outputs. A first optical coupler having a first optical path length is included. The first output of the first MMI coupling device is optically coupled to the first input of the second MMI coupling device through the first optical coupler. A second optical coupler having a second optical path length is also included. The second output of the first MMI coupling device is optically coupled to the second input of the second MMI coupling device through the second optical coupler. The first optical path length of the first optical coupler is different than the second optical path length of the second optical coupler.

Abstract: An optical network is formed of multiple H-tree distribution devices, separated into different waveguide layers. The optical network receives an input optical signal, such as an optical clock signal, and makes duplicate copies of that input signal. The duplicate copies are routed through the connected H-tree distribution devices, which are arranged to produce identical, synchronized copies of the clock signal. The network can take the form of a 1×2N device, where 2N represents the number of these output signals. The H-tree distribution devices forming the network are of varying size and may be formed in different waveguide layers with different index of refraction differentials between the H-tree devices and surrounding claddings. In some forms, the optical network is integrated with optical-to-electrical converters, i.e., photodetectors, which take the optical output signals and convert them to synchronized electrical signals that may be communicated to digital circuits.

Abstract: Broadband optical switches based on adiabatic couplers having a pair of asymmetric waveguides with variable curvature sections include in a 2×2 configuration based on a Mach-Zehnder interferometer two such adiabatic couplers, and in a 1×2 or 2×1 configuration an adiabatic coupler and an Y-splitter. Each adiabatic coupler includes two waveguide branches of different but constant widths having curved sections with varying radii, separated over a coupling length by a changing spacing therebetween and blending in an asymmetric intersection area, and two symmetric branches. In the 2×2 switch, the two adiabatic couplers face each other with their respective symmetric branches, and are connected by the two identical arms along a main propagation axis in a mirror image. The utilization of the variable curvature adiabatic couplers in silica MZI switches on a silicon substrate provides switches with an exceptional broadband range (1.2-1.

Abstract: A 2 to n divider with integrated optics, where n is an integer greater than or equal to 2, including at least one 2 to 2 optical divider element in a substrate. The optical divider element comprises a first and a second guide with widths equal to W1 and W2, respectively. The first and second guides are suitable for dividing an input light wave input into one of the guides, into a first and second output wave transported by the first and second guides respectively according to a determined division ratio. These first and second guides have at least three parts. A first part where the first and second guides move toward each other, a second part where the first and second guides are approximately parallel to each other and a third part where the first and second guides gradually separate from each other.

Abstract: A submarine branching unit is disclosed that includes a termination for each of at least three line cables and a termination to sea ground. A relay is positioned between each pair of cable terminations. When current flows between two of the cables, the intermediary relay will become energized and cause a contact to connect the third cable to the sea-ground termination. To avoid dangerous surges in current to sea ground when a relay trips, a current limiter is placed in series with the sea ground termination.

Abstract: A flexible optoelectronic circuit is assembled on and released from a substrate, and therefore independent of a substrate. The substrate includes semiconductor substrates having a release layer. The release layer is etched to release the optoelectronic circuit such that the resulting circuit is flexible. Both optical elements, such as waveguides, and conductive elements are formed in layers, generally between insulating layers. The elements may be formed and patterned using standard semiconductor manufacturing techniques.

Abstract: A tapered waveguide improves insertion loss occurring at the slab/waveguide interface of an optical array waveguide grating (AWG). The tapered waveguide has two segments. The first segment decreases from a first thickness, nearest the slab of the AWG to a second thickness moving away from the slab. The second segment has a substantially constant or uniform thickness equal to the second thickness of the first segment. The second segment may also have a swallowtail shape comprising a forked end having two sidewalls tapered back towards the first segment. Light that would otherwise be lost at the slab/waveguide interface is instead captured by the tapered waveguide which laterally channels the light back into the waveguides thus mitigating insertion loss.