Abstract: A spot-size converter includes first and second waveguide structures. The first waveguide structure extends longitudinally along a waveguide axis from a first end to a second end and is configured to support a first optical mode at the first end. The second waveguide structure is formed within the first waveguide structure. The second waveguide structure extends longitudinally between the first end and the second end. The second waveguide structure is configured to support a second optical mode at the second end. The second optical mode has a different diameter than the first optical mode. The second waveguide structure includes a waveguide core that has a first cross-sectional area in a first plane normal to the waveguide axis at the first end and a second cross-sectional area in a second plane normal to the waveguide axis at the second end. The second cross-sectional area is larger than the first cross-sectional area.

Abstract: An optical device includes a silicon substrate, a waveguide formed of a thin film that is laminated on the silicon substrate and that is made of a perovskite oxide with a large electro-optic effect as compared to lithium niobate, and a cladding layer that covers the waveguide. Further, the optical device includes ground electrode that has a ground potential and a signal electrode that is arranged at a position facing the ground electrode and that applies driving voltage to the waveguide.

Abstract: An optical device includes an X-cut substrate, and a first waveguide and a second waveguide each being formed on the substrate and having a folding structure. The optical device includes a first signal electrode to generate a first electric field, and a second signal electrode to generate a second electric field with a reverse phase as compared to the first field. The first waveguide includes a first waveguide on an outward side to which the first field is applied from the first signal electrode, and a first waveguide on a return side to which the second field is applied from the second signal electrode. The second waveguide includes a second waveguide on the outward side to which the first field is applied from the first signal electrode, and a second waveguide on the return side to which the second field is applied from the second signal electrode.

Abstract: A mode loss difference compensator of the present disclosure includes a main waveguide configured to allow propagation of N or more modes (where N is an integer of 3 or more), a first auxiliary waveguide having, at one end thereof, a first coupling portion configured to mode-convert an LP0n mode (where n is an integer of 2 or more) propagating in the main waveguide into a fundamental mode in the first auxiliary waveguide and transfer the fundamental mode from the main waveguide to the first auxiliary waveguide and having, at the other end thereof, a second coupling portion configured to mode-convert the fundamental mode propagating in the first auxiliary waveguide into the LP0n mode (where n is an integer of 2 or more) in the main waveguide and transfer the LP0n mode from the first auxiliary waveguide to the main waveguide, and a second auxiliary waveguide having, at one end thereof, a third coupling portion configured to convert a higher-order mode, other than any LP0n mode (where n is an integer of 2 or mor

Abstract: An optical modulator includes: an optical modulation element that is configured to generate two modulated light beams, each of which is modulated by two sets of electrical signals, and that includes a plurality of signal electrodes; a plurality of signal input terminals, each of which inputs an electrical signal; a relay substrate on which a plurality of signal conductor patterns and a plurality of ground conductor patterns are formed, the relay substrate being configured to propagate the two sets of electrical signals by two pairs of the adjacent signal conductor patterns; and a housing, in which the at least two signal conductor patterns including at least one parts mounting part including electrical circuit elements are configured such that first signal propagation directions, which are signal propagation directions at the parts mounting parts, are different from each other.

Abstract: A lens for terahertz radiation, which can be used in an antenna arrangement, comprises a cylindrical lens body made of silicon having a planar front surface and a planar back surface. The lens body has a front body region which forms a silicon metamaterial with a relative permittivity that decreases in a lateral direction with increasing radial distance from a cylinder axis. A back body region is immediately adjacent to the front body region and extends to the back surface. It consists of bulk silicon having a laterally constant relative permittivity. The front body region comprises holes that are distributed on the front surface in rings that are concentric with respect to the cylinder axis. The holes extend from the front surface to respective hole bottoms at an equal bottom level in a depth direction. The hole bottoms interface with the back body region.

Abstract: In a waveguide having a given ?, a low-loss waveguide bend is realized while the curvature radius is kept small. In an optical waveguide in which a first waveguide and a second waveguide are connected, a clothoid tapered waveguide bend is inserted between the first waveguide and the second waveguide. In the clothoid tapered waveguide bend, the waveguide width continuously changes from a first waveguide width at a connection point of the first waveguide to a second waveguide width at a connection point of the second waveguide, the curvature radius continuously changes from a first curvature radius at the connection point of the first waveguide to a second curvature radius at the connection point of the second waveguide, the first waveguide width and the second waveguide width are different from each other, and the first curvature radius and the second curvature radius are different from each other.

Abstract: Described are heat assisted magnetic read-write heads that include a coupler, a waveguide, a transducer, and appurtenant structures.

Abstract: A sensor network, which includes a sensor controller serially coupled to a plurality of sensor modules, is configured to program the sensor modules so as to transfer measurement data to the sensor controller and to synchronize the sensor modules to picosecond accuracy via on-chip or on-module custom circuits and a physical layer protocol. The sensor network has applications for use in PET, LiDAR or FLIM applications. Synchronization, within picosecond accuracy, is achieved through use of a picosecond time digitization circuit. Specifically, the picosecond time digitization circuit is used to measure on-chip delays with high accuracy and precision. The delay measurements are directly comparable between separate chips even with voltage and temperature variations between chips.

Abstract: An optical device includes a thin film Lithium Niobate (LN) layer, a first optical waveguide, and a second optical waveguide. The thin film LN layer is an X-cut or a Y-cut LN layer. The first optical waveguide is an optical waveguide that is formed on the thin film LN layer along a direction that is substantially perpendicular to a Z direction of a crystal axis of the thin film LN layer. The second optical waveguide is an optical waveguide that is routed and connected to the first optical waveguide. At least a part of a core of the first optical waveguide is made thicker than a core of the second optical waveguide.

Abstract: Structures for an edge coupler and methods of fabricating such structures. The structure includes a substrate, a first waveguide core, and a second waveguide core positioned in a vertical direction between the first waveguide core and the substrate. The second waveguide core includes a taper and an inverse taper longitudinally positioned adjacent to the taper.

Abstract: An optical device configured to be coupled with an optical fiber is described. The optical device includes a waveguide, a low-confinement waveguide, and a low-confinement layer. The waveguide includes a high-confinement waveguide, which has a first index of refraction. The low-confinement waveguide is optically coupled with the high-confinement waveguide. At least a portion of the low-confinement waveguide has a second index of refraction less than the first index of refraction. The low-confinement waveguide has a thickness of at least a mode diameter in a portion of the optical fiber. The low-confinement layer is adjacent to a portion of the low-confinement waveguide. The low-confinement layer has a third index of refraction less than the second index of refraction.

Abstract: An optical frequency comb generation system includes an optical waveguide portion having a uniform width, a first chirped Bragg grating disposed at one end of the optical waveguide portion and a second chirped Bragg grating disposed at the other end of the optical waveguide portion. The first chirped Bragg grating includes at least a first periodic variation having a first refractive index and a second periodic variation having a second refractive index. The second chirped Bragg grating includes the at least first and second periodic variations. A first cavity associated with a first resonant frequency extends between the first periodic variation of the first chirped Bragg grating and the first periodic variation of the second chirped Bragg grating. A second cavity associated with a second resonant frequency extends between the second periodic variation of the first chirped Bragg grating and the second periodic variation of the second chirped Bragg grating.

Abstract: A tap coupler includes a mode generation unit, a separation unit, and an output unit. The mode generation unit generates, in accordance with a discontinuous portion disposed on a travelling path of signal light that is propagating, a first mode of the signal light and a second mode that is different from the first mode. The separation unit separates, when the first mode and the second mode are input from the mode generation unit, the first mode and the second mode. The output unit outputs branch light in accordance with a transition of the second mode received from the separation unit.

Abstract: A utility pole deterioration detection system includes a cable (20) disposed in a utility pole (10), the cable (20) containing a communication optical fiber, a receiving unit (331) configured to receive an optical signal containing a pattern that changes according to a deterioration state of the utility pole (10) from at least one optical fiber contained in the cable (20), and a detection unit (332) configured to detect a deterioration state of the utility pole (10) based on the pattern.

Abstract: An optical modulator is disclosed that includes an optical resonator structure. The optical resonator structure includes at least one non-linear portion, the at least one non-linear portion comprising at least one radial junction region. The at least one radial junction region is formed between at least first and second materials, respectively, having different electronic conductivity characteristics. A principal axis of the at least one radial junction region is oriented along a radius of curvature of the at least one non-linear portion. The optical modulator includes an optical waveguide that is coupled to the at least one non-linear portion of the optical resonator structure.

Abstract: An optical waveguide adapter assembly comprises a solid core optical waveguide extending between a free end and a coupled end and having a solid waveguiding core with an associated first optical mode field size; a hollow core optical waveguide extending between a free end and a coupled end and having a hollow waveguiding core with an associated second optical mode field size; and an optical mode field adapter extending between a first end and a second end and having a waveguiding core configured to change an optical mode field of a waveguided optical signal substantially between the first optical mode field size at the first end of the optical mode field adapter and the second optical mode field size at the second end of the optical mode field adapter, the first end of the optical mode field adapter joined to the coupled end of the solid core optical waveguide to provide optical coupling between the waveguiding core of the solid core optical waveguide and the waveguiding core of the optical mode field adapter

Abstract: Configurations for an optical splitter are disclosed. The optical splitter may include an input waveguide, a free propagation region, and an array of output waveguides. The input waveguide may be sufficiently narrow that the light in the free propagation region may diffract and provide the same optical intensity at far field angles across a wide wavelength range. The input waveguide may have a high V number in a vertical dimension and a low V number in a horizontal dimension. Because all of the wavelengths of light diffract at the same angle in the free propagation region, once the light reaches the output waveguides, the light may have similar optical power at each of the output waveguides. Additionally, the output waveguides may vary in width and spacing to mitigate the non-uniform optical power distribution of the phase front of light.

Abstract: A fibre optic cable structure (300) suitable for fibre optic sensing with an improved sensitivity to an environmental parameter is described. The structure (300) includes an optical fibre (301) and a bend inducer (304) responsive to the environmental parameter to control bending of the optical fibre. The bend inducer (304) is configured to adopt a first configuration, that induces a first curvature of the optical fibre, at a first value of the environmental parameter and to adopt a second configuration at a second, different, value of the environmental parameter that induces a second, different, curvature of the optical fibre. By action of the bend inducer (304) a change in value of the environmental parameter imparts a bending force on the optical fibre.

Abstract: Performance improvement of an all-optical analog-to-digital converter (AOADC) addresses both RF and optical modeling of a leaky waveguide based optical spatial light modulator (SLM) using electro-optic (E-O) material. The E-O polymer provides improved sensitivity for SLM and achieves a broader bandwidth due to better velocity matching between RF and optical waves.

Abstract: Provided is an optical densitometer for measuring a density of a gas or liquid of interest, the optical densitometer comprising: a light source capable of introducing light into a core layer; a detector capable of receiving the light that has propagated through the core layer; and an optical waveguide, the optical waveguide comprising: a substrate; and the core layer comprising a light propagation portion capable of propagating the light in an extending direction of the light propagation portion, and a diffraction grating portion, the diffraction grating portion comprising a diffraction grating region and an extension region connected to the diffraction grating region, and a first optical coupling region included in the extension region and a second optical coupling region included in the light propagation portion being optically coupled with respect to the light propagating through the core layer.

Abstract: Structures including a waveguide core and methods of fabricating a structure including a waveguide core. The structure comprises a photonics chip including a first chip region, a second chip region, a first waveguide core in the first chip region, and a second waveguide core in the second chip region. The first chip region adjoins the second chip region along a boundary. The first waveguide core includes a first tapered section, and the second waveguide core includes a second tapered section positioned across the boundary from the first tapered section. The first tapered section has a first width dimension that increases with increasing distance from the boundary, and the second tapered section has a second width dimension that increases with increasing distance from the boundary.

Abstract: A photonic integrated circuit (PIC) in which some optical waveguides have laterally tilted waveguide cores used to implement passive polarization-handling circuit elements, e.g., suitable for processing polarization-division-multiplexed optical communication signals. Different sections of such waveguide cores may have continuously varying or fixed lateral tilt angles. Different polarization-handling circuit elements can be realized, e.g., using different combinations of end-connected untilted and laterally tilted waveguide-core sections. In some embodiments, laterally tilted waveguide cores may incorporate multiple-quantum-well structures and be used to implement active circuit elements. At least some embodiments beneficially lend themselves to highly reproducible fabrication processes, which can advantageously be used to achieve a relatively high yield of the corresponding PICs during manufacture.

Abstract: An optomechanical inertial reference mirror combines an optomechanical resonator with a reflector that serves as an inertial reference for an atom interferometer. The optomechanical resonator is optically monitored to obtain a first inertial measurement of the reflector that features high bandwidth and high dynamic range. The atom interferometer generates a second inertial measurement of the reflector that features high accuracy and stability. The second inertial measurement corrects for drift of the first inertial measurement, thereby resulting in a single inertial measurement of the reflector having high bandwidth, high dynamic range, excellent long-term stability, and high accuracy. The reflector may be bonded to the resonator, or formed directly onto a test mass of the resonator. With a volume of less than one cubic centimeter, the optomechanical inertial reference mirror is particularly advantageous for portable atomic-based sensors and systems.

Abstract: Roughly described, an optical device includes a first waveguide having a first core sheathed by a first cladding, and a second waveguide having a second core. A terminal portion of second core is disposed under a terminal portion of the first core and sheathed by the first core. The refractive index of the second core is higher than that of the first core, and the index of the first core, at least in the terminal portion of the first waveguide, is higher than that of the first cladding. The second core is structured under the terminal portion of the first core so that light traveling in the second core and directed toward the end of the second core is guided along the second core and coupled into the first core, and vice-versa.

Abstract: Structures for an optical coupler and methods of fabricating a structure for an optical coupler. The structure includes a first waveguide core having a first tapered section and a second waveguide core having a second tapered section positioned adjacent to the first tapered section of the first waveguide core. The second tapered section is positioned with a lateral offset in a lateral direction relative to the first tapered section. The second tapered section is positioned with a vertical offset in a vertical direction relative to the first tapered section.

Abstract: A guided-wave-driven metasurface antenna includes an input for receiving a guided wave; an output for outputting a free-space wave; and a spatial frequency mixer connected between the input and the output for converting the guided wave to the free-space wave. The spatial frequency mixer is implemented by a metasurface of the antenna. The superheterodyne metasurface can be fabricated with high accuracy using lithography step similar to conventional waveguides made by the well-established semiconductor processing technology, making their integration with PICs straightforward.

Abstract: To reduce the size while being able to accurately monitor light of a plurality of wavelengths. An optical multiplexing circuit includes: a plurality of branching units each configured to divide light output from a corresponding one of a plurality of input waveguides; a multiplexing unit configured to multiplex beams each being one beam of the light divided by each of the plurality of branching units; an output waveguide configured to output the light multiplexed by the multiplexing unit; and a plurality of monitoring waveguides each configured to output another beam of the light divided by each of the plurality of branching units, wherein at least one monitoring waveguide of the plurality of monitoring waveguides includes a bent waveguide constituted by a rib-shaped waveguide.

Abstract: A whispering gallery mode inertial sensor includes a whispering gallery mode resonator; an evanescent coupler configured to couple with an evanescent field of the resonator so that light is transmitted to and received from the resonator by the coupler; a displacement sensor configured to determine a displacement of the resonator according to the light received from the resonator by the coupler; a controller configured to determine an acceleration and/or rate of rotations experienced by the resonator based on the displacement of the resonator, the controller being further configured to apply a restoring force to the resonator in a closed feedback loop based on the displacement of the resonator in order to maintain a predetermined mechanical state of the resonator; and a timing sensor configured to determine a timing signal based on an optical frequency comb produced by the resonator.

Abstract: An optical waveguide device includes a pair of waveguides. One of the waveguides includes a first core formed in a conversion region and a third core formed in an exit region. The other of waveguides includes a second core formed in the conversion region and a fourth core formed in the exit region. Cross-sectional areas of the first and second cores are different from each other at an input end. Distributions of a refractive index of the first and second cores are respectively asymmetric in a perpendicular direction. A quantitative relation provided at the input end between an effective refractive index of an odd mode of TE0 and an effective refractive index of an even mode of TM0 is opposite to the quantitative relation provided at the output end. Cross-sectional areas of the third and fourth cores are different from each other at an output end.

Abstract: A light interference system is provided. The light interference system includes a light source configured to generate a measurement light; a fiber configured to propagate therethrough the measurement light; and a measurement device. The fiber includes a single-mode fiber, a multimode fiber and a connector connecting the single-mode fiber and the multimode fiber. A tip end of the fiber is formed of the multimode fiber, and an end surface of the tip end of the fiber is configured to emit the measurement light to a measurement target object and receive a reflection light from the measurement target object. The measurement device is configured to measure physical property of the measurement target object based on the reflection light.

Abstract: The present disclosure relates to a method of forming a tapered optical fiber, where the optical fiber has a cladding encasing a core and has an initial outer diameter. The method involves applying opposing forces to spaced apart sections of the optical fiber. The spaced apart sections define a length portion representing a waist region. While applying the opposing forces, simultaneously applying heat to the waist region to gradually produce a taper of the optical fiber within the waist region. The taper has a first diameter at a midpoint of the waist region which is less than the initial outer diameter. An etch operation is then performed by chemically etching at least a subportion of the waist region of the optical fiber to reduce the subportion to a second diameter which is less than the first diameter.

Abstract: Embodiments of the disclosure provide an optical polarizer with a varying vertical thickness, and methods to form the same. An optical polarizer according to the disclosure may include a first waveguide core over a semiconductor substrate. A first cladding material is on at least an upper surface of the first waveguide core. A second waveguide core over the first waveguide core and above the first cladding material. The second waveguide core includes a first segment having a vertical thickness that varies along a length of the first segment. A second cladding material is at least partially surrounding the second waveguide core. Transfer of one of a transverse electric (TE) mode signal and a transverse magnetic (TM) mode signal from the first waveguide core to the second waveguide core occurs between the first segment of the second waveguide core and the first waveguide core.

Abstract: There is provided an optical waveguide that performs propagation only in a reference mode at a first wavelength. Communication is performed using light of a second wavelength that enables the optical waveguide to perform propagation in at least a first order mode in addition to the reference mode. When light entering the optical waveguide deviates with respect to an optical axis or deviates angularly, propagation is performed in at least the first order mode in addition to the reference mode, the first order mode being generated due to the deviation with respect to the optical axis or the angular deviation. This results in a reduction in a loss of coupling of optical power. This makes it possible to relax the accuracy with respect to a deviation with respect to an optical axis or an angular deviation, and thus to reduce costs.

Abstract: A method for making a multimode interference (MMI) coupler with an arbitrary desired splitting ratio includes forming a thin-film of silicon-nitride material overlying a SOI substrate. The method further includes obtaining geometric parameters of a standard MIMI coupler including a rectangular MMI block and one input port and two output ports in taper shape with one of standard splitting ratios under self-imaging principle which is close to the desired splitting ratio. Additionally, the method includes tunning the input port to an off-center position at front edge of the MMI block. The method further includes making a first output port to a first off-center position flushing with a side edge of the MMI block, adjusting a second output port to a second off-center position. The method includes tunning the MMI block to obtain optimized geometric parameters for approaching the selected arbitrary splitting ratio, and etching the thin-film of silicon-nitride material.

Abstract: Structures for a wavelength-division multiplexing filter and methods of forming a structure for a wavelength-division multiplexing filter. The structure includes a first slab having a first perimeter, a first waveguide core coupled to the first slab, and a plurality of second waveguide cores coupled to the first slab. A second slab is positioned to overlap with the first slab. The second slab includes a second perimeter and openings that are distributed inside the second perimeter. The openings of the second slab penetrate through the second slab.

Abstract: An optical coherent transceiver comprising a polarization and phase-diversity coherent receiver and a polarization and phase-diversity modulator on the same substrate interfaced by three grating couplers, one grating coupler coupling in a signal, one grating coupler coupling in a laser signal, and a third grating coupler coupling out a modulated signal.

Abstract: An optical device includes a first multi-mode waveguide, a first optical coupler coupled to the first multi-mode waveguide, the first coupler being tapered and curved, and a first single-mode waveguide having a first end coupled to the first optical coupler. The optical device maybe used in an optical delay device. A method of propagating light in a first multi-mode waveguide toward a first optical coupler, propagating the light in the first optical coupler toward a first single-mode waveguide, the first optical coupler being tapered and curved, and propagating the light along the first single-mode waveguide is also disclosed.

Abstract: The present invention has an object to provide an optical fiber test method and an optical fiber test apparatus for measuring a mode dependent loss and an inter-modal crosstalk in a fundamental mode and a first higher-order mode at a connection point of a few-mode fiber. In the optical fiber test method and test apparatus according to the present invention, the mode dependent loss and the inter-modal crosstalk in the fundamental mode and the first higher-order mode at the connection point are calculated by using an approximation expression of an inter-modal coupling efficiency that is obtained in approximating electric field distributions of the fundamental mode and the first higher-order mode in a few-mode fiber by Gaussian function and Hermite Gaussian function.

Abstract: An integrated wavelength division multiplexer is described. The integrated wavelength division multiplexer may include a first waveguide core defining a first propagation axis and configured to guide light of a first wavelength and light of a second wavelength, and a second waveguide core defining a second propagation axis and configured to guide the light of the second wavelength. A first portion of the second propagation axis for which the first waveguide core and second waveguide core may be overlapping is oriented at a non-zero angle relative to the first propagation axis. The first waveguide core and second waveguide core may be configured relative to each other to adiabatically couple the light of the second wavelength between the first and second waveguide cores.

Abstract: An apparatus for laser processing a material including an optical fibre, at least one squeezing mechanism, and a lens. The optical fibre is a multimode optical fibre in which laser radiation propagates in a first optical mode and in a second optical mode. The squeezing mechanism includes at least one periodic surface defined by a pitch. The periodic surface is located adjacent to the optical fibre. The pitch couples the first and second optical modes together. The first optical mode is defined by a first mode order. The second optical mode is defined by a second mode order which is higher than the first mode order. The squeezing mechanism squeezes the periodic surface and optical fibre together with a squeezing force thereby coupling the first optical mode to the second optical mode.

Abstract: The present invention relates to a polymer optical waveguide including: a core; an under-cladding; and an over-cladding, in which the polymer optical waveguide includes a coupling section and an optical waveguide section that are provided along a light propagation direction, the polymer optical waveguide includes portions having different core widths along the light propagation direction, and when a core width at a portion a having a narrowest core width is denoted Wa (?m) and a core height at the portion a is denoted Ha (?m), Ha is 1.3 ?m or more and 4.5 ?m or less, and Ha/Wa is 1.15 or less.

Abstract: An optical mode converter for coupling between photonic integrated circuit (PIC) and optical fiber of different mode sizes is illustrated. The optical mode converter includes a waveguide assembly including a Single waveguide structure, a Multi-layer waveguide structure, and a Transitional waveguide structure. The Single waveguide structure includes a single waveguide. The dimension and propagation constant of a first end, of the single waveguide, is similar to a waveguide of a photonic integrated circuit (PIC). Furthermore, the Multi-layer waveguide structure included a multi-layer waveguide. Further, the Transitional waveguide structure is formed at a transitional structure. The Transitional waveguide structure allows transition of an optical mode between the Single waveguide structure and Multi-layer waveguide structure.

Abstract: An optical modulator includes an input waveguide having a first width enabling a propagation of a light-beam in a single-mode, a tapered waveguide having an input end connected to the input waveguide and an output end having a second width larger than the first width, an optical demultiplexer having an input port connected to the output end, a first output port connected to a first arm waveguide, and a second output port connected to a second arm waveguide connected to the second output port, a first electrode disposed on the first arm waveguide, and a second electrode disposed on the second arm waveguide. The first arm waveguide has a third width larger than the first width. The first arm waveguide is located within a first strip region. The first strip region having a fourth width twice as large as the third width.

Abstract: Structures for a directional coupler and methods of fabricating a structure for a directional coupler. A first waveguide core has a first section, a second waveguide core has a second section laterally adjacent to the first section, a third waveguide core has a first taper, a second taper, and a third section longitudinally positioned between the first taper and the second taper, and a fourth waveguide core has a first taper, a second taper, and a fourth section longitudinally positioned between the first taper and the second taper. The fourth section is laterally adjacent to the third section, and the third section and the fourth section are positioned either over or under the first section and the second section.

Abstract: One optical antenna coupler includes a base body having a first waveguide and a second waveguide and a plurality of antenna coupler elements positioned above an upper surface of the base body that are adapted to be irradiated by an incident light. The plurality of antenna coupler elements includes at least one variable optical characteristics (VOC) antenna coupler element that comprises a VOC material, wherein the at least one VOC antenna coupler element is operatively coupled to a first energy source. The VOC antenna coupler element is adapted to be transitioned from a metallic state to an insulator state and vice versa. In the metallic state, substantially all of the incident light is directed out of the optical antenna coupler via the first waveguide and, in the insulator state, substantially all of the incident light is directed out of the optical antenna coupler via the second waveguide.

Abstract: An optical phase shifter may include a waveguide core that has a top surface, and a semiconductor contact that is laterally displaced relative to the waveguide core and is electrically connected to the waveguide core. A top surface of the semiconductor contact is above the top surface of the waveguide core. The waveguide core may include a p-type core region and an n-type core region. A p-type semiconductor region may be in physical contact with the n-type core region of the waveguide core, and an n-type semiconductor region may be in physical contact with the p-type core region of the waveguide core. A phase shifter region and a light-emitting region may be disposed at different depth levels, and the light-emitting region may emit light from a phase shifter region that is in a position adjacent to the light-emitting region.

Abstract: Systems and methods for coupling optical fiber to a photonic chip are described. The apparatus may include a low index contrast waveguide overlapping a region of a photonic chip, a high index contrast waveguide at least partially embedded within the overlapped region of the photonic chip, where the high index contrast waveguide comprises a tapered region and a fixed-width routing region, and where the tapered region comprises an adiabatic crossing region and a wide waveguide region connecting the adiabatic crossing region and the fixed-width routing region. A rate of increase of the width of the high index contrast waveguide with respect to position along the length of the high index contrast waveguide is substantially non-linear within the adiabatic crossing region and substantially asymmetric about a minimum slope point.

Abstract: An optical phase shifter may include a waveguide core that has a top surface, and a semiconductor contact that is laterally displaced relative to the waveguide core and is electrically connected to the waveguide core. A top surface of the semiconductor contact is above the top surface of the waveguide core. The waveguide core may include a p-type core region and an n-type core region. A p-type semiconductor region may be in physical contact with the n-type core region of the waveguide core, and an n-type semiconductor region may be in physical contact with the p-type core region of the waveguide core. A phase shifter region and a light-emitting region may be disposed at different depth levels, and the light-emitting region may emit light from a phase shifter region that is in a position adjacent to the light-emitting region.

Abstract: An optical device comprises first, second and third elements fabricated on a common substrate. The first element comprises an active waveguide structure supporting a first optical mode, the second element comprises a passive waveguide structure supporting a second optical mode, and the third element, at least partly butt coupled to the first element, comprises an intermediate waveguide structure supporting intermediate optical modes. If the first optical mode differs from the second optical mode by more than a predetermined amount, a tapered waveguide structure in at least one of the second and third elements facilitates efficient adiabatic transformation between the second optical mode and one of the intermediate optical modes. No adiabatic transformation occurs between any of the intermediate optical modes and the first optical mode. Mutual alignments of the first, second and third elements are defined using lithographic alignment marks.