Abstract: An electro-optical memory cell having a non-volatile programmable refractive index and a method of making. The memory cell includes: a waveguiding structure having a transition metal oxide with oxygen vacancies; a plurality of electrodes for applying an electrical field; and an optical detector for detecting a state of the memory cell. The method includes: fabricating a waveguiding structure having a transition metal oxide with oxygen vacancies; positioning a plurality of electrodes for application of an electric field; arranging the transition metal oxide and the electrodes such that when an electric field is applied, the oxygen vacancies migrate in a direction that has a component which is radial relative to a center of the beam path; applying the electric field thereby programming the refractive index to set a state of the memory cell; and detecting the state of the memory cell using an optical detector.

Abstract: Devices, systems and methods of using same where hybrid substrate materials are provided with a substantially uniform surface to provide uniformity of properties, including interaction with their environments. Uniform surfaces are applied as coatings over, e.g., hybrid metal/silica, metal/polymer, metal/metal surfaces to mask different chemical properties of differing regions of the surface and to afford a protective surface for the hybrid structure.

Abstract: Provided is an optical waveguide manufacturing method that makes the thickness of a clad layer in the vicinity of a core portion uniform. A first lamination film is fabricated by forming a clad layer by forming a first curable resin layer for clad formation on a first base film and curing the first curable resin layer, and forming a core portion by forming a second curable resin layer for core formation having a higher refractive index than that of the clad layer after cured on the clad layer and selectively curing the second curable resin layer. A second lamination film is fabricated by forming a clad layer by forming a third curable resin layer for clad formation on a second base film and curing the third curable resin layer.

Abstract: Passive optical components may be used to tap the optical power, e.g., from fibers of a wavelength switch system. The passive optical components are realized by a standard photonics light-wave circuit (PLC) integrated to the fiber collimator array of the wavelength switch system. The PLC includes multiple waveguide paths that optically couple optical signals from one or more fiber ports to one or more corresponding free space optical component ports. Optical signals traveling through these waveguide paths are tapped by one or more optical taps and coupled to one or more corresponding tap ports. Each optical tap is located such that an optical signal is tapped after it is coupled into one of the waveguide paths.

Abstract: A self-written branched optical waveguide is formed. A laser beam 2 from a laser source (not shown) is focused with a lens 3 onto the face of incidence 10 of an optical fiber 1. The laser beam of an LP11 mode was emitted from the face of emergence 11, and “bimodal” light intensity peaks were arranged in the horizontal direction (1.A). A slide glass 4 coated with a photocurable resin gel 5 was placed horizontally (1.B). A single linear cured material 61 was formed as the LP11-mode laser beam was emitted from the face of emergence 11 of the optical fiber 1 (1.C). A branch portion 62 was then formed at a distance L from the face of emergence 11 of the optical fiber 1, which was followed by the growth of two cylindrical cured materials 63a and 63b. The two cylindrical cured materials 63a and 63b were linear branches, and formed an angle of about four degrees. An optical waveguide 60 thus formed was composed of cured materials 61, 62, 63a, and 63b (1.D).

Abstract: An optical apparatus including a 360-degree star coupler with derivative structure(s) and applications to optical imaging, optical communications and optical spectroscopy.

Abstract: Optical waveguide and manufacturing of an optical waveguide comprising embossing at least one groove into a first substrate by rolling, applying at least a second substrate into the groove and covering at least the groove with a third substrate such that the groove constitutes an optical waveguide for optical signal transmission.

Abstract: Systems and methods for manipulating light with high index contrast waveguides clad with crystalline substances having that exhibit large nonlinear electro-optic constants ?2 and ?3. Waveguides fabricated on SOI wafers and clad with crystalline materials such as barium titanate are described. Embodiments of waveguides having slots, electrical contacts, and input waveguide couplers are discussed. Waveguides having closed loop structures (such as rings and ovals) as well as linear or serpentine waveguides, are described. Optical signal processing methods, such as optical rectification and optical modulation, are disclosed.

Abstract: Various embodiments of the present invention are directed to photonic-based interconnects for transmitting data encoded in electromagnetic signals between electronic mosaics. In one embodiment of the present invention, a photonic-based interconnect comprises a first photonic node coupled to a second photonic node via a waveguide. The first photonic node is coupled to a first electronic mosaic and is configured to transmit electromagnetic signals encoding data generated by the first electronic mosaic to a second electronic mosaic and receive electromagnetic signals encoding data generated by the second electronic mosaic. The second photonic node is coupled to the second electronic mosaic and is configured to transmit electromagnetic signals encoding data generated by the second electronic mosaic to the first electronic mosaic and receive electromagnetic signals encoding data generated by the first electronic mosaic.

Abstract: A disclosed waveguide film cable includes a waveguide formed on a film. The waveguide film cable includes a coating film made of a material having a Young's modulus smaller than or equal to the Young's modulus of a material that forms the film and/or the waveguide and coats partially or entirely the film and/or the waveguide.

Abstract: A periodic structure is to be successively formed over an extensive area with a uniaxial laser beam. Such method includes irradiating a uniaxial laser beam near an ablation threshold to a surface of a material; and executing an overlapped scanning on the irradiated region, so as to cause an ablation by interference between an incident beam and a surface scattered wave along the material surface; increasing the scattered wave; causing an interference at an interval equal to a wavelength of the laser beam, to thereby cause spontaneous formation of a periodic structure. The periodic structure can be made to have a different ripple spacing by changing an incident angle of the laser beam to the material surface. When the laser incident beam has an angle, the ripple spacing can be changed by changing a scanning direction.

Abstract: A substrate on which an optical element is mounted is provided, including: an optical element; an optical circuit substrate which is formed by an optical waveguide layer having a core portion and cladding portions; and an electrical circuit substrate on which is provided a mounting portion that is used for mounting the optical element, wherein the optical element is mounted on the electrical circuit substrate via the optical circuit substrate and wherein the optical circuit substrate has an optical element mounted thereon and is provided with a receptor structure having a conductive portion that conducts electricity between an electrode of the optical element and an electrode of the electrical circuit substrate.

Abstract: The optical sensor contains an optical waveguide (1) with a substrate (104), waveguiding material (105), a cover medium (106) and a waveguide grating structure (101-103). By means of a light source (2), light can be emitted to the waveguide grating structure (101-103) from the substrate side and/or from the cover medium side. (101-103). With means of detection (11), at least two differing light proportions (7-10) radiated from the waveguide (1) can be detected. For carrying out a measurement, the waveguide can be immovably fixed relative to the light source (2) and the means of detection (11). The waveguide grating structure (101-103) itself consists of one or several waveguide grating structure units (101-103), which if so required can be equipped with (bio-)chemo-sensitive layers. The sensor permits the generation of absolute measuring signals.

Abstract: In one embodiment, the apparatus includes a substrate having a surface and an optical waveguide having a ridge-shaped semiconductor optical core, the ridge-shaped semiconductor optical core being located over the surface. The apparatus may further include a first semiconductor slab being in contact with a first portion of the ridge-shaped semiconductor optical core, and a second semiconductor slab being in contact with a second portion of the ridge-shaped semiconductor optical core, the second semiconductor slab being farther from the surface than the first semiconductor slab.

Abstract: A planar lightwave circuit is provided which can be easily fabricated by an existing planar-lightwave-circuit fabrication process, which can lower the propagation loss of signal light and which can convert inputted signal light so as to derive desired signal light. A planar lightwave circuit having a core and a clad which are formed on a substrate, has input optical waveguide(s) (111) which inputs signal light, mode coupling part (112) for coupling a fundamental mode of the inputted signal light to a higher-order mode and/or a radiation mode, or mode re-coupling part (113) for re-coupling the higher-order mode and/or the radiation mode to the fundamental mode, and output optical waveguide(s) (114) which outputs signal light. The mode coupling part or the mode re-coupling part is an optical waveguide which has core width and/or height varied continuously.

Abstract: A method comprises: forming an optical device on a device substrate; forming a first optical waveguide on the device or device substrate; forming a second, structurally discrete optical waveguide on a structurally discrete waveguide substrate; and assembling the optical device, first waveguide, or device substrate with the second waveguide or waveguide substrate. The device and first waveguide are arranged for transferring an optical signal between the device and the first waveguide. Upon assembly the first and second waveguides are positioned between the device and waveguide substrates and are relatively positioned for transferring the optical signal therebetween via optical transverse coupling. The first or second optical waveguide is arranged for transferring the optical signal therebetween via substantially adiabatic optical transverse coupling with the first and second waveguides so positioned.

Abstract: An optical waveguide having a core region with a substantially rectangular cross-section with a selected aspect ratio of width to height. Embodiments include devices incorporating the optical waveguide and methods for using the optical waveguide.

Abstract: The present invention provides a two-dimensional photonic crystal in which an absolute photonic band gap (PBG), i.e. a photonic band gap that is effective for both the TE-polarized light and the TM-polarized light within a predetermined wavelength range, is created with an adequate bandwidth. The body 21 is provided with holes 22 arranged in a triangular lattice pattern, where the basic shape of the hole is an equilateral triangle. This shaping and arranging of the holes creates an absolute PBG. Each corner of the equilateral triangle is cut along an arc to leave an adequate distance between the neighboring holes (i.e. an adequate width of the connecting portion of the body). This design makes it possible to enlarge each hole 22 while ensuring an adequate strength of the two-dimensional photonic crystal. This construction creates an absolute PBG having a large width.

Abstract: Embodiments of an optical device, an array of optical devices, and a technique for fabricating the optical device or the array are described. This optical device is implemented on a substrate (such as silicon), and includes a thermally tunable optical waveguide that has good thermal isolation from its surroundings. In particular, a portion of a semiconductor in the optical device, which includes the optical waveguide, is free standing above a gap between the semiconductor layer and the substrate. By reducing the thermal coupling between the optical waveguide and the external environment, the optical device can be thermally tuned with significantly less power consumption.

Abstract: An optical waveguide for a luminescent device capable of efficiently leading light beams propagating through a core outwardly to cause light emission, and a manufacturing method thereof. The optical waveguide for a luminescent device includes an under cladding layer 2, a core 3 formed in a predetermined portion of a surface of the under cladding layer 2, and an over cladding layer 4 formed on the surface of the under cladding layer 2 so as to cover the core 3. The over cladding layer 4 includes holes 41 formed in a predetermined portion thereof and extending to the core 3. The holes 41 are filled with a coating material 5 having a refractive index not less than that of the above-mentioned core 3.

Abstract: An optical waveguide and method of making are disclosed. The method of making includes forming a layer on a substrate of a substantially optically transparent material. The layer includes an inner area and an outer area. A sufficient number of voids can be created in the inner area to form a first index of refraction. A plurality of the voids have a dimension that is less than a wavelength of the light beam. A sufficient number of voids can be created in the outer area to form a second index of refraction less than the first index.

Abstract: A photonic guiding device and methods of making and using are disclosed. The photonic guiding device comprises a large core hollow waveguide configured to interconnect electronic circuitry on a circuit board. A reflective coating covers an interior of the hollow waveguide to provide a high reflectivity to enable light to be reflected from a surface of the reflective coating. A collimator is configured to collimate multi-mode coherent light directed into the hollow waveguide.

Abstract: A method of producing a planar substrate having waveguide channels, which method comprises: (i) providing a tube (6) of a substrate material; (ii) depositing silica layers (110) on the inside of the tube (6), the silica layers (110) being doped with a photosensitive material; (iii) drawing the tube (6) so that the cross-sectional size of the tube (109) is reduced; (iv) before or after the reducing of the cross-sectional size of the tube (6), causing the tube (6) to collapse into a flat shape by applying a low pressure to the tube, whereby the deposited silica layers together form a photosensitive silica layer (111); (v) cutting to required lengths the tube (6) which has been collapsed and reduced in cross-sectional size; and (vi) using laser writing to define waveguide channels in the cut lengths of the tube (6) and thereby to produce the planar substrate having the waveguide channels.

Abstract: An active area includes a photonic-crystal optical waveguide formed by periodically arranging a plurality of holes in a primary plane direction of an active-area core layer in an active-area growth portion. A passive area includes a passive optical waveguide formed in a passive-area growth portion. An effective refractive index of a growth structure of the active-area growth portion is larger than an effective refractive index of a growth structure of the passive-area growth portion, and an active layer has a gain at a zero group-velocity point positioned on a high-frequency side of a dispersion curve of the photonic-crystal optical waveguide.

Abstract: The invention provides a waveguide with a waveguide core having longitudinal sidewall surfaces, a longitudinal top surface, and a longitudinal bottom surface that is disposed on a substrate. An interface layer is disposed on at least one longitudinal sidewall surface of the waveguide core. A waveguide cladding layer is disposed on at least the waveguide core sidewall and top surfaces, over the interface layer. The waveguide of the invention can be produced by forming a waveguide undercladding layer on a substrate, and then forming a waveguide core on the undercladding layer. An interface layer is then formed on at least a longitudinal sidewall surface of the waveguide core, and an upper cladding layer is formed on a longitudinal top surface and on longitudinal sidewall surfaces of the waveguide core, over the interface layer.

Abstract: An optical waveguide structure comprises a substrate (12) having first and second groove arrays (8, 10), including grooves (8a-8g, 10a-10h), and an optical waveguide (14), having cladding and core (14b) layered on the substrate between the groove arrays to vertically align the core with cores (2a, 4a) of optical fibers (2, 4) positioned on the grooves. The waveguide has at least one first port (20) aligned with a groove (8d) of the first groove array and at least one second port (22) aligned with a groove (10e) of the second groove array. The number of second ports is equal to or greater than that of the first ports. A ratio of the number of grooves of the second groove array relative to the number of grooves of the first groove array is less than a ratio of the number of the second ports relative to the number of first ports.

Abstract: A method for fabricating a nanometer slot waveguide comprises applying a spacer layer to a first waveguide structure, wherein the first waveguide structure includes a waveguide layer and a substrate layer and the waveguide layer has a refractive index greater than the substrate layer. A second waveguide structure is applied to the spacer layer, wherein the second waveguide structure includes a waveguide layer and a substrate layer, and the waveguide layer has a refractive index greater than the substrate layer. The substrate layer of the second waveguide structure is removed to create an intermediate waveguide structure and portions of the intermediate waveguide structure are removed to create a nanometer slot waveguide structure.

Abstract: Parallel-aligned core layers are formed by patterning a core sheet laminated on a base plate, and a clad/core bonded body is formed by laminating a cladding sheet. The base plate is peeled from one surface of the clad/core bonded body and a dicing tape is pasted on the other surface of the clad/core bonded body. An inclined surface is formed by bevel-cutting both end portions of the core layers. Clad/core bonded pieces are formed by straight-cutting the cladding sheet between core layers and on an outside of outermost core layers. A mask is disposed on the clad/core bonded pieces, and then a metal film is formed on the inclined surface. The clad/core bonded pieces are separated individually by peeling the pieces from the dicing tape after the mask is removed. The clad/core bonded piece is brought into contact with the liquid adhesive coated on a circuit substrate and aligned thereon. Then, the liquid adhesive is cured.

Abstract: A method of forming a low loss crystal quality waveguide is provided. The method includes providing a substrate and forming a dielectric layer on the substrate. A channel is formed by etching a portion of the dielectric layer. A selective growth of a Si Ge, or SiGe layer is performed in the area that defines the channel. Furthermore, the method includes thermally annealing the waveguide at a defined temperature range.

Abstract: An AC-coupled differential drive circuit for an optical modulator is utilized, where a common “node” is defined between top (or bottom) plates of the modulator arms themselves (the “arms” of a modulator taking the form of MOS capacitors). A low pass filter is disposed between the differential driver output and the modulator's common node to provide the desired AC coupling by filtering out the DC bias voltage of the driver circuit itself without the need for a separate, external AC coupling capacitor. An independent, adjustable DC potential can then be applied to the common node, and will appear in a balanced manner across each arm of the modulator to provide the desired DC bias for the modulator independent of the DC bias of the driver circuit.

Abstract: An apparatus comprises an optical waveguide, a grating for coupling light into the waveguide, and an optical element for splitting a light beam into a plurality of beams that strike the grating at different angles of incidence.

Abstract: The present invention relates to a semiconductor optoelectronic waveguide having a nin-type hetero structure which is able to stably operate an optical modulator. On the upper and lower surfaces of the core layer determined for the structure so that electro-optical effects are effectively exerted at an operating light wavelength and are provided with intermediate clad layers having a band gap which is greater than that of the core layer 11. Respectively on the upper and the lower surface of the intermediate clad layer are provided the clad layers having the band gap which is greater than those of the intermediate clad layers. On the upper surface of the clad layer are sequentially laminated a p-type layer and an n-type layer. In the applied voltage range used under an operating state, a whole region of the p-type layer and a part or a whole region of the n-type layer are depleted.

Abstract: A photonic crystal is configured with wavelength converting material to act as a concentrator for electromagnetic energy. The concentrator may also be configured with energy conversion devices to convert the electromagnetic energy into another form of energy.

Abstract: A suspension board with circuit includes a metal supporting board including a board trench portion, an insulating base layer formed on a surface of the metal supporting board, a conductive pattern formed on a surface of the insulating base layer, and an optical waveguide provided to overlap the board trench portion when projected in a thickness direction of the metal supporting board. At least a part of the optical waveguide is positioned closer to the conductive pattern than to a back surface of the metal supporting board.

Abstract: Consistent with the present disclosure, a package is provided in which the PLC substrate, for example, is bonded to the underyling carrier though a limited contact area. The rest of the substrate is detached from the carrier so that stresses are applied to a limited portion of the PLC substrate. The PLC itself, however, is provided over that portion of the substrate that is detached from the carrier, and thus experiences reduced stress. Accordingly, high modulus adhesives, as well as solders, may be used to bond the PLC substrate to the carrier, thereby resulting in a more robust mechanical structure.

Abstract: A method for fabricating a distributed Bragg reflector waveguide is disclosed, which includes forming a first distributed Bragg reflector on a substrate; forming a sacrificial pattern on the first distributed Bragg reflector; forming a second distributed Bragg reflector on the sacrificial pattern and the first distributed Bragg reflector; and removing the sacrificial pattern. A distributed Bragg reflector waveguide is also disclosed.

Abstract: Methods and devices relating to a sensor for use in detecting and monitoring molecular interactions. A silicon waveguide sensing element is provided along with a layer of silicon. A silicon oxide layer is also provided between the waveguide element and the layer of silicon. The sensing element is adjacent to an aqueous solution in which the molecular interactions are occurring. A light beam travelling in the silicon waveguide creates an evanescent optical field on the surface of the sensing element adjacent to the boundary between the sensing element and the aqueous medium. Molecular interactions occurring on this surface affect the intensity or the phase of the light beam travelling through the waveguide by changing the effective refractive index of the medium. By measuring the effect on the intensity, phase, or speed of the light beam, the molecular interactions can be detected and monitored in real time.

Abstract: Light having components of frequencies f0, f+1 and f?1 outputted from an optical modulator (10) is monitored, a second light detection means (14b) measures the power P2 of all the components, and a first light detection means (14a) measures the power P1 with frequency f0 component cut out by a filter means (13). Based on these light receiving powers (P1) and (P2), phase differences imparted by the respective DC electrodes of Mach-Zehnder optical waveguides (MZ-A, MZ-B, MZ-C) of the optical modulator (10) are controlled. The control is performed to minimize the light receiving power (P1) and to maximize the light receiving power (P2).

Abstract: A backlight assembly for feeding illuminating light to a passive display panel is disclosed. The backlight assembly comprises a plurality of waveguides being formed and/or embedded in at least one substrate and arranged to feed illuminating light to each sub-pixel position of the passive display panel in a manner such that each pixel region is illuminated by at least two waveguides, wherein each waveguide of the at least two waveguides is disposed to illuminate one sub-pixel position of the pixel region by a respective color channel.

Abstract: Fiber optic sensors commonly require a 180 degree turnaround to form a continuous optical circuit. Methods and apparatus for providing 180 degree turnarounds in a fiber optic system that include a shorter radius turnaround then provided by micro-bending the optic fiber are desired. An embodiment of a turnaround apparatus includes a first optic fiber pigtail, a second optic fiber pigtail, and an optical waveguide forming a U-shaped path having an input end optically connected to a first end of the first pigtail and an output end optically connected to a first end of the second pigtail.

Abstract: The present invention relates generally to wavelength conversion devices and laser projection systems incorporating the same. According to one embodiment of the present invention, wavelength conversion devices are provided without limitation of their field of use to laser projection systems. For example, the wavelength conversion device may comprise an axial waveguide portion and a pair of lateral planar waveguide portions confined between a pair of relatively low index cladding layers. The effective index of refraction in the axial waveguide portion of the waveguide region and the effective index of refraction in the lateral planar waveguide portions of the waveguide region are established such that the relatively low intensity laterally distributed parasitic light is characterized by a scattering angle ? that is at least as large as the beam divergence angle of the relatively high intensity light propagating in the axial waveguide portion.

Abstract: An optical waveguide includes: a core portion through which light propagates; a cladding portion enclosing the core portion along a direction of light propagation, and a colored resin for position recognition marking, the optical waveguide having substantially planar outer surfaces including principal surfaces thereof, and the colored resin being embedded in the optical waveguide at a position that does not substantially overlap the core portion when viewed from a direction perpendicular to a principal surface of the optical waveguide and does not substantially contact the core portion.

Abstract: A shared light pipe is set forth for transmitting light generated by a message waiting LED in a mobile communication device, in one direction, and transmitting ambient or surrounding light, in an opposite direction, to a light sensor for controlling a display backlight of the device. The light pipe includes an elongated first portion having a first end for receiving and transmitting light and external surfaces for reflecting light there through via total internal reflection (TIR), a second portion coextensive with the first portion for outputting light received at the first end and reflected through the first portion, and a second branch coextensive with the first portion for receiving and transmitting light for output at the first end.

Abstract: Provided is a silicon array waveguide grating (AWG) device comprising a silicon array waveguide in which a plurality of optical waveguides formed of a lower cladding layer, a silicon core, and an upper cladding layer are arranged, wherein the variation of the refractive index of the silicon core is positive, and the upper cladding layer is formed of polymer, the variation of refractive index of which according to temperature is negative, which is opposite to the silicon core, and the cross-section of the silicon core varies between different areas to adjust the variation of the effective refractive index of the optical waveguide according to temperature.

Abstract: A method of manufacturing optical waveguide device, comprising steps of: preparing optical waveguide including under cladding layer and protruding core pattern formed on the under cladding layer; preparing mold having protrusions for shaping recesses for fitting with predetermined portions of the core pattern; preparing board provided with light-receiving/emitting element mounted thereon; placing the mold around the light-receiving/emitting element for positioning top surfaces of the protrusions of the mold over light-receiving/emitting portions of the light-receiving/emitting element; filling the mold with sealing resin material and hardening the material in the mold to form sealing resin layer having recesses for fitting with the core pattern; after removing the sealing resin layer from the mold, the core pattern are fitted with the recesses of the resin layer to optically couple the light-receiving/emitting portions and the optical waveguide; and forming an over cladding layer for covering the remaining po

Abstract: A method of fabricating a microchannel plate includes forming a plurality of pores in a silicon substrate. The plurality of pores is oxidized, thereby consuming silicon at surfaces of the plurality of pores and forming a silicon dioxide layer over the plurality of pores. At least a portion of the silicon dioxide layer is stripped, which reduces a surface roughness of the plurality of pores. A semiconducting layer can be deposited onto the surface of the silicon dioxide layer. The semiconducting layer is then oxidized, thereby consuming at least some of the polysilicon or amorphous silicon layer and forming an insulating layer. Resistive and secondary electron emissive layers are then deposited on the insulating layer by atomic layer deposition.

Abstract: In a light emitting device, efficiency and stability are improved. A light emitting device 10 includes a three-dimensional photonic crystal 20. The three-dimensional photonic crystal includes a first defect part 70 forming a resonator including an active medium, a second defect part 80 forming a waveguide for taking out light generated by the resonator, a P clad part 40 formed of a P-type semiconductor, and a N clad part 50 formed of a first N-type semiconductor. The second defect part is provided only in the N clad part among the P clad part and the N clad part. At least a part of the second defect part is formed of a second N-type semiconductor and constitutes a heat radiation unit which radiates a heat to the outside.

Abstract: An optical device and an optical transmitter are provided. The optical device includes a substrate, a first optical waveguide that may be formed in the substrate and may have a bending portion, and a second optical waveguide that intersects with the bending portion of the first optical waveguide, wherein a groove may be formed outside the bending portion of the first optical waveguide in the substrate.

Abstract: The invention provides a waveguide comprising a channel 12 on an optical substrate 11, the refractive index of the channel being higher than that of the substrate. The waveguide includes at least one guide layer 13 arranged on the channel, the index of said guide layer being higher than that of the substrate. In addition, the channel 12 is integrated in the substrate 11. advantageously, the waveguide further includes a covering layer 14 deposited on the guide layer 13, the index of said covering layer being lower than that of the guide layer and lower than that of the channel. The invention also provides a method of fabricating the waveguide.

Abstract: An optical time delay apparatus comprises: a multi-wavelength optical source; a diffractive element set imparting a wavelength-dependent delay on signals routed from the source to a 1×N optical switch; and N diffractive element sets routing signals from the 1×N switch to an output port. The optical propagation delay between the source and the output port varies according to the operational state of the source and the 1×N switch. A photodetector may receive the time-delayed signal at the output port.