Abstract: An optical fiber for a temperature sensor and a power device monitoring system that can measure temperatures at different measurement positions by a simple construction are provided. An optical fiber for the sensor 10 comprises a temperature assurance FBG 20 and temperature measurement FBGs 30 as FBGs wherein the refractive index of a core changes periodically. Wavelength band of light incident to the optical fiber for the sensor 10 includes Bragg wavelengths of the temperature assurance FBG 20 and the temperature measurement FBGs 30. The power device monitoring system 1 measures temperatures of the temperature assurance FBG 20 and the temperature measurement FBGs 30 based on their Bragg wavelengths.

Abstract: Mechanically tunable electromagnetic and photonic devices featuring enhanced spectral tunability with minimal mechanical movement are provided. These nano/micro-electromechanically (N/MEMS) tunable elements, including filters and pixels, rely on leaky-mode resonance effects in subwavelength photonic lattices that constitute periodic wavelengths. Such elements can operate in reflection (bandstop) or transmission (bandpass) modes, and can be arranged in one-dimensional or two-dimensional arrays, or operated as single units, and their spectral regions are controlled by the element design. Input electromagnetic radiation illuminates the element and is then filtered, modulated, analyzed or tuned by the element. Mechanical motion alters the structural symmetry, and therefore, the tuning properties, of the nanostructured subwavelength resonance elements.

Abstract: The invention relates to a monofrequency optical filter, including reflective elements which are formed on one surface of a dielectric support layer and which define at least one periodic array of parallel grooves passing across same. The periodicity, height, and width of said periodic groove array are selected so as to form a structure, the wavelength of which can be selected from within a predetermined range of wavelengths. According to the invention, the thickness and refractive index of the support layer are selected so that said layer forms a half-wave plate for a wavelength of the predetermined wavelength range. The filter, when in contact with the surface of the support layer opposite the surface on which the groove array is formed, includes a medium, the refractive index of which is less than that of the support layer so as to obtain a guided mode that resonates in the support layer.

Abstract: A waveguide apparatus includes a planar waveguide and at least one optical diffraction element (DOE) that provides a plurality of optical paths between an exterior and interior of the planar waveguide. A phase profile of the DOE may combine a linear diffraction grating with a circular lens, to shape a wave front and produce beams with desired focus. Waveguide apparati may be assembled to create multiple focal planes. The DOE may have a low diffraction efficiency, and planar waveguides may be transparent when viewed normally, allowing passage of light from an ambient environment (e.g., real world) useful in AR systems. Light may be returned for temporally sequentially passes through the planar waveguide. The DOE(s) may be fixed or may have dynamically adjustable characteristics. An optical coupler system may couple images to the waveguide apparatus from a projector, for instance a biaxially scanning cantilevered optical fiber tip.

Abstract: A light-receiving device of the present disclosure includes a light-trapping sheet, and a photoelectric conversion section optically coupled thereto. The light-trapping sheet includes: a light-transmitting sheet; and a plurality of light-coupling structures arranged in an inner portion of the light-transmitting sheet. The light-coupling structure includes first, second and third light-transmitting layers. A refractive index of the first and second light-transmitting layers is smaller than that of the light-transmitting sheet; and a refractive index of the third light-transmitting layer is larger than those of the first and second light-transmitting layers. The third light-transmitting layer has a diffraction grating parallel to the light-transmitting sheet. At least a part of the photoelectric conversion section is located along an outer edge of at least one of the surfaces of the light-transmitting sheet.

Abstract: A method for performing a multi-stage dilation of optical fibers is described, the method comprising performing successive dilation steps such that the adiabatic condition is maintained throughout the fiber. There is also described various optical devices employing such multi-stage dilated optical fibers, as well as methods of manufacture of the optical devices.

Abstract: Embodiments herein include a resilient add-drop module for use in one of multiple access subnetwork nodes forming an access subnetwork ring. The module comprises a dual-arm passive optical filter and a cyclic arrayed waveguide grating (AWG). The dual-arm passive optical filter is configured to resiliently drop any wavelength channels within a fixed band uniquely allocated to the access subnetwork node from either arm of the access subnetwork ring and to resiliently add any wavelength channels within the fixed band to both arms of the access subnetwork ring. The cyclic AWG is correspondingly configured to demultiplex wavelength channels dropped by the dual-arm filter and to multiplex wavelength channels to be added by the dual-arm filter. Configured in this way, the module in at least some embodiments advantageously reduces the complexity and accompanying cost of nodes in an optical network, while also providing resilience against fiber and node failures.

Abstract: In one example, a composite processor includes a circuit board, a first processor element package, and a second processor element package. The circuit board has an optical link and an electrical link. The first processor element package includes a substrate with an integrated circuit, a sub-wavelength grating optical coupler, and an electrical coupler coupled to the electrical link of the circuit board. The second processor element package includes a substrate with an integrated circuit, a sub-wavelength grating optical coupler, and an electrical coupler coupled to the electrical link of the circuit board. The sub-wavelength grating optical coupler of the first processor element package, the optical link of the circuit board, and the sub-wavelength grating optical coupler of the second processor element package collectively define an optical communications path between the substrate of the first processor element package and the substrate of the second processor element package.

Abstract: A semiconductor package and a semiconductor device including the same. The semiconductor package includes: a package substrate; a plurality of connection elements that are disposed on the package substrate; and a semiconductor chip that includes at least one optical input/output element that transmits/receives an optical signal to/from the outside at an optical input/output angle with respect to a direction perpendicular to a bottom surface of the package substrate, and is electrically connected to the package substrate through the plurality of connection.

Abstract: An optical device including a diffraction grating structure. The device provides optical coupling that allows the diffraction efficiency and the coupling efficiency of signal light whose direction to travel is changed (or diffracted) by a grating to be independently determined. The optical device includes: a first layer forming one end of an optical waveguide; and a second layer disposed on the first layer and having a lower refractive index than the first layer. According to one embodiment, the second layer includes a diffraction grating structure that diffracts light that has entered the second layer from the first layer and outputs the light from the second layer to the first layer. In another embodiment, a third layer disposed on the second layer and includes the diffraction grating structure.

Abstract: A method and system for multi-mode integrated receivers are disclosed and may include receiving an optical signal from an optical fiber coupled to a chip comprising a photonic circuit. The photonic circuit may comprise an optical coupler, one or more multi-mode optical waveguides, and a detector. The received optical signal may be coupled to a plurality of optical modes in the one or more multi-mode optical waveguides, which are communicated to a detector to generate an electrical signal from the communicated modes. The optical coupler may comprise a grating coupler. The chip may comprise a CMOS chip, and the optical fiber may comprise a single-mode or a multi-mode fiber. The detector may comprise a germanium or silicon-germanium photodiode, and/or a waveguide detector. The optical fiber may be coupled to a top surface of the chip and the multi-mode optical waveguides may comprise rib waveguides.

Abstract: A sensor which reacts on influences from an environment. The sensor includes a zero-order diffractive color filter. The zero-order diffractive color filter includes a high-index waveguide layer, a zero-order diffractive grating structure and a layer of an reactive material, wherein the reactive material is in contact with the environment and wherein the reactive material changes its optical properties upon interaction with the environment. The reactive material is embedded in the waveguide layer and/or the reactive material is located at a maximum distance d from the waveguide layer. The distancing is effected by an intra layer having a low index of refraction.

Abstract: A sensor for sensing at least one biological target or chemical target is provided. The sensor includes a membrane includes a membrane material that supports generation and propagation of at least one waveguide mode, where the membrane material includes a plurality of voids having an average size <2 microns. The sensor also includes at least one receptor having structure for binding to the target within the plurality of voids, and an optical coupler for coupling light to the membrane sufficient to generate the waveguide mode in the membrane from photons incident on the optical coupler.

Abstract: A passive arrayed-waveguide-grating (AWG) router that can be used to implement the dual functionality of a wavelength router and a 3-dB power splitter for one of its wavelength channels while functioning as a conventional wavelength router for the other wavelength channels. The passive AWG router can advantageously be used, e.g., in a WDM-PON system to reduce the insertion-loss disparity between the various wavelength channels that are being used to broadcast optical signals from an optical line terminal located at the service provider's central office, through the passive AWG router, to a plurality of optical network units located near the end users.

Abstract: An arrayed waveguide grating provided with a first slab waveguide formed on a substrate; a second slab waveguide formed on the substrate; a first input/output waveguide connected to the first slab waveguide; a second input/output waveguide connected to the second slab waveguide; two or more channel waveguide groups connecting the first and second slab waveguides, each of the channel waveguide groups formed of an aggregate of a plurality of channel waveguides having path lengths sequentially becoming longer by a predetermined path length difference; and an optical filter arranged in at least one of the first and second slab waveguides.

Abstract: A fiber Bragg grating interrogator assembly is described. Examples of the fiber Bragg grating interrogator assembly include an optical fiber including a fiber Bragg grating having a variable Bragg wavelength (?B) and a dynamic range of interest (??dyn,B) over which the Bragg wavelength (?B) can shift during use. The fiber Bragg grating interrogator assembly also includes a response analyzer having a spectrally selective device with an input port to which the optical fiber is operably connected, and a plurality of output ports of which each output port is associated with a respective spectral range (??n). The spectral ranges (??n, ??n+1, ??n+2) of each at least three successive output ports partially overlap, such that the FBG's Bragg wavelength (?B) falls inside the spectral ranges (??n, ??n+1, ??+2) of at least three successive output ports over the dynamic range of interest (??dyn,B) of the FBG.

Abstract: A photonic integrated device comprises a waveguide embedded in a photonic substrate. The waveguide has a waveguide radiation exit surface and the waveguide is optically connected to a two dimensional grating. The photonic integrated device also comprises a two dimensional grating having a plurality of curved elongate scattering elements. The two dimensional grating is adapted for diffracting radiation received from the waveguide toward a direction out of the photonic substrate and the curved elongate scattering elements are oriented with respect to the waveguide such that, for points of the scattering elements which can be irradiated by radiations stemming from the waveguide, normal lines to at least the curved elongate scattering element closest to the waveguide radiation exit surface do not substantially intersect with the waveguide radiation exit surface of the waveguide.

Abstract: A method of spectral beam combining comprising the steps of projecting a plurality of laser beamlets of different wavelengths onto a first spectrally dispersive element, spatially chirping the plurality of beamlets via the first spectrally dispersive element, rearranging the spatially chirped beamlets with a beam redirecting element, and combining the beamlets into a single output beam via a second spectrally dispersive element.

Abstract: A Head Up Display can be utilized to find light from an energy source. The Head Up Display includes a first waveguide having a first input coupler and a first output coupler. The Head Up Display can also include a second waveguide having a second input coupler and a second output coupler. The first waveguide has a first major surface and the second waveguide has a second major surface, which are disposed approximately parallel to each other. The first waveguide and the second waveguide are positioned as a combiner and allowing viewing an outside feed and information from an image source. The first input coupler diffracts light in the first field of view into the first waveguide and light in a second field of view reaches the second input coupler and is diffracted into the second waveguide.

Abstract: The present invention provides an optical splitter and a system, including: an optical divider, a ribbon fiber, and tributary fibers, where the optical divider is configured to divide an input optical signal into at least two optical signals for output; one end of the ribbon fiber is connected to the optical divider, and the other end of the ribbon fiber is connected to the tributary fibers, where a grating array is disposed on the ribbon fiber; and the grating array includes at least two Bragg gratings, different Bragg gratings correspond to different tributary lines of the optical divider, and the number of Bragg gratings included in the grating array is the same as the number of optical signals output by the optical divider; which solves a problem that additional connection loss is increased because an existing splitter needs to be connected to each link fiber by using an optical connector.

Abstract: An optical add/drop multiplexer including one or more optical drop multiplexers connected in free space or fused by optical fiber pigtails, a wavelength blocker with an input port connected to an output port of the optical drop multiplexer through the fusion of the fiber pigtails, one or more optical add multiplexers connected in free space or fused by fiber pigtails, a digital signal processor, an analog-to-digital signal converter, a digital-to-analog converter, and a plurality of electronic control and feedback loops for tuning and scanning an optical wavelength.

Abstract: An optical semiconductor element includes: a grating base layer including a projection-recess structure disposed over a substrate; and a grating cover layer including a group III-V semiconductor having three or more elements, wherein the grating cover layer includes a first region which is disposed over recessed portions of the grating base layer and which has a compositional ratio of a group III-V semiconductor having a first refractive index, and a second region which is disposed over projecting portions of the grating base layer and which has a compositional ratio of a group III-V semiconductor having a second refractive index that is smaller than the first refractive index, wherein the grating base layer includes a group III-V semiconductor having a third refractive index that is smaller than the first refractive index.

Abstract: A system and method are disclosed for providing uniform color distribution of light emitted from a light source to an eye box in a near eye display (NED). An example of the system and method uses an optical element including two or more waveguides optimized to different colors of the visible light spectrum. The optical element further includes one or more polarization state generators for controlling the polarization of light incident on the waveguides to facilitate coupling of light into a matched waveguide, and to impede coupling of light into unmatched waveguides.

Abstract: An optical multiplexer/de-multiplexer (MUX/de-MUX) includes a two-dimensional pattern of features in a propagation region that conveys an optical signal having wavelengths. A given feature in this pattern has a characteristic length and the features have an average pitch, both of which are less than fundamental smallest of the wavelengths divided by an effective index of refraction of the propagation region. Moreover, an optical device in the optical MUX/de-MUX images and diffracts the optical signal using a reflective geometry, and provides the imaged and diffracted optical signal to output ports. For example, the optical device may include an echelle grating.

Abstract: A binocular display includes a waveguide. A convex spherical mount has a fixed position relative to the waveguide. A light engine includes a concave spherical mount that adjustably mates with the convex spherical mount.

Abstract: In one aspect of the invention, roughly stated, Applicants have discovered that a compensation material within slot elongated in a direction parallel to a segment of waveguide in an arrayed waveguide grating apparatus can compensate for both first and second order change in refractive index of the base waveguide material over temperature. Unlike the transverse slots of conventional linear athermalization techniques, the elongated slot generally parallel to the base material defines a composite waveguide section having a second order effective index of refraction temperature dependency which can be utilized to accurately minimize the temperature dependence of the overall optical path length to both the first and second order. The techniques described herein are also generalizeable to neutralization of the optical path length temperature dependence to any order.

Abstract: An optical de-multiplexer (de-MUX) that includes an optical device that images and diffracts an optical signal using a reflective geometry is described, where a free spectral range (FSR) of the optical device associated with a given diffraction order abuts FSRs associated with adjacent diffraction orders. Moreover, the channel spacings within diffraction orders and between adjacent diffraction orders are equal to the predefined channel spacing associated with the optical signal. As a consequence, the optical device has a comb-filter output spectrum, which reduces a tuning energy of the optical device by eliminating spectral gaps between diffraction orders of the optical device.

Abstract: Grating couplers that enable efficient coupling between waveguides and optical fibers are disclosed. In one aspect, a grating coupler includes a transition region that includes a wide edge and tapers away from the edge toward a waveguide disposed on a substrate. The coupler also includes a sub-wavelength grating disposed on the substrate adjacent to the edge. The grating is composed of a series of non-uniformly distributed, approximately parallel lines and separated by grooves with a depth to output light from the grating with TM polarization.

Abstract: Techniques related to optical devices are described herein. In an example, an optical device includes (a) an input optical channel and a corresponding output optical channel, and (b) an assembly of sub-wavelength grating layers aligned to optically couple the input optical channel to the output optical channel.

Abstract: An optical element includes a multicore optical fiber, the multicore optical fiber including an inner core and at least one peripheral core arranged around the inner core and having an effective refractive index different from that of the inner core, and an optical fiber grating formed at the multicore optical fiber to cause an optical signal to be coupled between different cores among the inner core and the at least one peripheral core. The optical element allows a signal of a specific wavelength to be dropped added from an optical signal. Since the optical element may be fabricated easily, designed in a small size and mass-produced reproducibly at low costs, the optical element may be advantageously utilized for an optical communication network such as a wavelength division multiplexing network, an ultra-high speed optical communication system, an optical sensor system or the like.

Abstract: An apparatus for optical coupling comprises a substrate, a first waveguide formed on the substrate and includes a grating structure directing light in a first direction, and a second waveguide formed on the first waveguide and including an angled portion directing the light in a second direction different from the first direction.

Abstract: This document discusses, among other things, a connector for an optical imaging probe that includes one or more optical fibers communicating light along the catheter. The device may use multiple sections for simpler manufacturing and ease of assembly during a medical procedure. Light energy to and from a distal minimally-invasive portion of the probe is coupled by the connector to external diagnostic or analytical instrumentation through an external instrumentation lead. Certain examples provide a self-aligning two-section optical catheter with beveled ends, which is formed by separating an optical cable assembly. Techniques for improving light coupling include using a lens between instrumentation lead and probe portions. Techniques for improving the mechanical alignment of a multi-optical fiber catheter include using a stop or a guide.

Abstract: A method and system for coupling optical signals into silicon optoelectronic chips are disclosed and may include coupling one or more optical signals into a back surface of a CMOS photonic chip in a photonic transceiver, wherein photonic, electronic, or optoelectronic devices may be integrated in a front surface of the CMOS photonic chip. Optical couplers, such as grating couplers, may receive the optical signals in the front surface of the chip. The optical signals may be coupled into the back surface of the chips via optical fibers and/or optical source assemblies. The optical signals may be coupled to the optical couplers via a light path etched in the chips, which may be refilled with silicon dioxide. The chips may be flip-chip bonded to a packaging substrate. Optical signals may be reflected back to the optical couplers via metal reflectors, which may be integrated in dielectric layers on the chips.

Abstract: An optical switching device has multiple input ports and multiple output ports and is capable of switching a wavelength component from any of the input ports to any of the output ports. The optical switching device is configured with beam steering arrays that are controlled to provide the switching from any of the input ports to any of the output ports. The beam steering arrays may be microelectromechanical (MEMS) mirror arrays or liquid-crystal on silicon (LCOS) panels. In addition, an array of beam-polarizing liquid-crystal elements provides wavelength-independent attenuation.

Abstract: A leaky travelling wave array of optical elements provide a solar wavelength rectenna.

Abstract: A wavelength-selective cross-connect (WSXC) device configured to route any set of carrier wavelengths from a corresponding input port to any selected output port. The WSXC device comprises a diffraction grating and a beam-steering device optically coupled to one another and to the input/output ports using astigmatic optics. The astigmatic optics includes one or more cylindrical lenses configured to image one beam-steering surface onto another beam-steering surface to enable a continuous spectral response. The astigmatic optics may further include (i) a cylindrical Fourier lens that enables the WSXC device to convert a change in the angular beam steering performed by the beam-steering device into a corresponding image-spot displacement at the output ports and/or (ii) one or more cylindrical lenses configured to image the active surface of the beam-steering device onto the diffraction grating. Various unfolded configurations of the various embodiments of the WSXC device are also disclosed.

Abstract: A package for an arcuate planar lightwave circuit (PLC) chip includes a heater plate coupled to a base by a thick and soft support layer. The arcuate PLC is attached to the heater plate by soft adhesive. A hard adhesive is applied to a multi-waveguide end of the arcuate PLC, to additionally strengthen the attachment of the arcuate PLC to the heater plate. The structure allows the mechanical stress due to fiber pull/shock/vibration to be dissipated in the support layer without introducing large wavelength shifts in the arcuate PLC. The support layer also serves as a heat insulator, facilitating uniform heating of the arcuate PLC.

Abstract: An optical fiber coupler includes a clad optical fiber core having a coupling window formed therein. A laser source is joined to emit light into the core through the coupling window. The core has an output coupler for partially reflecting a portion of light and transmitting a portion as output. A Bragg grating is formed in the core having a pitch and being positioned to reflect light from said laser source toward the output coupler. The pitch is variable in response to a temperature change. A thermal control device is joined to the core for adjusting its temperature and the Bragg grating pitch. In other embodiments a mode convertor is provided to reduce the output modes to selected modes.

Abstract: A terahertz (THz) switch consisting of perfect conductor metamaterials is discussed in this invention. Specifically, we have built a THz logic block by combining two double-sided corrugated waveguides capable of slowing down the electromagnetic waves in the THz regime with a sub-wavelength cavity, having one or more grooves with shorter height than the grooves of the periodic corrugated waveguide. This new type of THz structure is called as the waveguide-cavity-waveguide (WCW). The new invention is based on our mathematical modeling and experimentation that confirms a strong electromagnetic field accumulation inside the tiny cavity which can confine EM field for a long time within a very small effective volume (Veff) to provide high quality (Q) factor. Therefore, an efficient THz switch can be designed to achieve ON-OFF switching functionality by modulating the refractive index n or extinction coefficient ? inside the switching junction.

Abstract: A method of, and apparatus for, inscribing a grating in an optical waveguide so as to reduce transverse inscription variations, are provided. The waveguide is exposed to multiple beams or interference patterns of actinic radiation from multiple azimuthal directions. The beams of actinic radiation are preferably split into a plurality of beams that have wave vectors with different longitudinal components, e.g., via gratings such as phase masks. The periods and phases of the interference patterns of the beams of actinic radiation are preferably matched. A control beam may be provided that does not hit the waveguide. A control loop optionally controls at least one of the position or orientation of at least one of the beams of actinic radiation. The gratings are, for example, Bragg gratings.

Abstract: A structure for coupling an optical signal between an integrated circuit photonic structure and an external optical fiber is disclosed as in a method of formation. The coupling structure is sloped relative to a horizontal surface of the photonic structure such that light entering or leaving the photonic structure is substantially normal to its upper surface.

Abstract: The inventive concept provides optic couplers, optical fiber laser devices, and active optical modules using the same. The optic coupler may include a first optical fiber having a first core and a first cladding surrounding the first core, a second optical fiber having a second core transmitting a signal light to the first optical fiber and a third cladding surrounding the second core, third optical fibers transmitting pump-light to the first optical fiber in a direction parallel to the second optical fiber; and a connector connected between the first optical fiber and the second optical fiber, the connector extending the third optical fibers disposed around the second optical fiber toward the first optical fiber, the connector comprising a third core connected between the first core and the second core and a fifth cladding surrounding the third core.

Abstract: Certain embodiments may include a laser system configured to emit collimated laser light, a beam diverging element configured to diverge the laser light to yield a range of propagation angles with a maximum angle greater than zero, and fiber coupling optics configured to direct the diverged laser light towards a spot of a cross-section of a fiber core of an optical fiber. As another example, certain embodiments may include a laser system configured to emit collimated laser light, a beam shaping element configured to shape the laser light into a beam with an elliptical cross-section, and fiber coupling optics configured to direct the diverged laser light towards a spot of a cross-section of a fiber core of an optical fiber, where the spot's center point is located at a distance from the cross-section's center point.

Abstract: A method for manufacturing a multi-dimensional target waveguide grating and volume grating with micro-structure quasi-phase-matching. An ordinary waveguide grating is used as a seed grating, and on this basis, a two-dimensional or three-dimensional sampling structure modulated with a refractive index, that is, a sampling grating, is formed. The sampling grating comprises multiple shadow gratings, and one of the shadow gratings is selected as a target equivalent grating. A sampled grating comprises Fourier components in many orders, that is, shadow gratings, a corresponding grating wave vector is [Formula 1], and the grating profile of all the shadow gratings changes with the sampling structure [Formula 2]. In a case where a seed grating wave vector [Formula 3] and a required two-dimensional or three-dimensional grating wave vector do not match, a certain Fourier periodic structure component of the Fourier components of the sampling structure is used to compensate for the wave vector mismatch.

Abstract: The invention relates to a waveguide, comprising a grating in at least a part of the waveguide, which waveguide comprises a coating, the coating comprising a polymer, which polymer comprises an aliphatic chain, which aliphatic chain is provided with hydrophilic side-chains. The invention further relates to a sensor system comprising a waveguide according to any one of the preceding claims, a light source, and a photo-detector.

Abstract: An optical semiconductor device, includes: a plurality of first diffraction grating layers disposed at a spacing from each other along first direction above first semiconductor layer, length of a lower surface of each of a plurality of first diffraction gratings along first direction being longer than a length of an upper surface of first diffraction grating; second diffraction grating layer disposed along first direction above first semiconductor layer, first and second diffraction grating layers being alternately disposed at a spacing from each other, a length of an upper surface of second diffraction grating layer along first direction being longer than the length of a lower surface of second diffraction layer; a diffraction grating including first and second diffraction grating layers; a second semiconductor layer disposed between first and second diffraction grating layers and under second diffraction grating layer; and third semiconductor layer disposed on first and second diffraction grating layers.

Abstract: An optical waveguide is provided having at least first and second diffraction regions, the first diffraction region being arranged to diffract image-bearing light propagating along the waveguide so as to expand it in a first dimension and to turn the image-bearing light towards the second diffraction region, the second diffraction region being arranged to diffract the image-bearing light so as to expand it in a second dimension and to release it from the waveguide as a visible image. The first diffraction region is formed by first diffraction grating embedded within the waveguide, arranged to present a substantially similar profile to the image-bearing light when incident upon the grating from a given angle above or below the grating such that the polarisation of the image bearing light is rotated by substantially similar amounts, but in opposite directions, by successive interactions with the first diffraction region.

Abstract: Exemplary apparatus for obtaining information for a structure can be provided. For example, the exemplary apparatus can include at least one first optical fiber arrangement which is configured to transceive at least one first electro-magnetic radiation, and can include at least one fiber. The exemplary apparatus can also include at least one second focusing arrangement in optical communication with the optical fiber arrangement. The second arrangement can include a ball lens, and be configured to focus and provide there through the first electro-magnetic radiation to generate the focused electro-magnetic radiation. Further, the exemplary apparatus can include at least at least one dispersive third arrangement which can receive a particular radiation (e.g., the first electro-magnetic radiation(s) and/or the focused electro-magnetic radiation), and forward a dispersed radiation thereof to at least one section of the structure.

Abstract: The disclosed embodiments provide systems and methods for mitigating lensing and scattering as an optical fiber is being inscribed with a grating. The disclosed systems and methods mitigate the lensing phenomenon by surrounding an optical fiber with an index-matching material that is held in a vessel with an integrated interferometer (e.g., phase mask, etc.). The index-matching material has a refractive index that is sufficient to reduce intensity variations of the actinic radiation within the optical fiber. Some embodiments of the system include different vessels for holding the index-matching material, with the vessel having an interferometer integrated into the vessel. These vessels permit the optical fiber to be surrounded by the index-matching material while the gratings are written to the optical fiber.

Abstract: A concave diffraction grating for integrated optics is constructed by replacing the reflective metallic part by either multiple thin elements of metal or multiple elements of dielectric material, each partially reflecting the light, and arranged on elliptical fashion in order to distribute the diffraction/reflection of light and provide aberration-free focusing, by combining diffraction condition and Bragg condition of these curved reflectors.