Abstract: An optical coupler for coupling a multimode waveguide and two or more other waveguides. In one embodiment, the optical coupler has an optical phase mask disposed between the multimode waveguide and two or more other waveguides. The optical phase mask imposes on the light passing therethrough a spatial phase pattern that causes selective mode-to-waveguide coupling between the multimode waveguide and the other waveguides. The optical coupler can be used, e.g., in transmitters and receivers of optical transverse-mode-multiplexed signals.

Abstract: There are provided: a core section provided so as to extend in a light-guiding direction in which incident light propagates; a photosensitive layer provided so as to extend in the light-guiding direction and peripherally enclose the core section, the photosensitive layer including a grating formed therein by irradiation of ultraviolet light having a predetermined wavelength; and a first cladding section provided between the core section and the photosensitive layer, the first cladding section having a lower refractive index than the core section and a lower photosensitivity than the photosensitive layer, the photosensitivity being a property in which a refractive index changes in response to irradiation with the ultraviolet light.

Abstract: An optical fiber coupler array capable of providing multiple low loss, high coupling coefficient interfaces between a predetermined number of low numerical aperture optical fibers and an optical waveguide device with at least a corresponding number of waveguide interfaces. The novel coupler array includes a plurality of coupler inner cores and a plurality of corresponding coupler outer cores, within a medium surrounding each plural outer core, and also includes a first end for interfacing with plural optical fibers and a second end for interfacing with a plurality of waveguide interfaces of an optical waveguide device. The sizes of the inner and outer cores are gradually reduced from the first end to the second end in accordance with at least one predetermined reduction profile.

Abstract: An optical device includes an input/output optical coupler, a waveguide and a waveguide fragment. The optical coupler is configured to separate a received optical signal into first and second signal components. The waveguide is connected to the optical coupler and configured to propagate the first signal component via a first propagation mode. The waveguide fragment is located adjacent to the first waveguide and is configured to couple light from the first waveguide that propagates therein by a different second propagation mode.

Abstract: An optical system is disclosed. The optical system includes first and second waveguides, a first dispersive element, and a coupler. The first waveguide is configured to support a first mode and a second mode of an optical input signal. The second mode being of a higher order than the first mode. The second waveguide has an input and an output and is configured to receive a portion of the optical input signal. The first dispersive element is disposed along a length of one of the first or second waveguides. The first dispersive element including a waveguide segment configured to induce a frequency-dependent phase shift in one of the portions of the optical input signal. The coupler is configured to couple the portion of the optical input signal in the second waveguide and the portion optical input signal in the first waveguide into the first waveguide. The coupling excites the second mode of the first waveguide to create a multimode optical signal.

Abstract: Optical fiber lasers and components for optical fiber laser. An optical fiber laser can comprise a fiber laser cavity having a wavelength of operation at which the cavity provides output light, the cavity including optical fiber that guides light having the wavelength of operation, the fiber having first and second lengths, the first length having a core having a V-number at the wavelength of operation and a numerical aperture, the second length having a core that is multimode at the wavelength of operation and that has a V-number that is greater than the V-number of the core of the first length optical fiber at the wavelength of operation and a numerical aperture that is less than the numerical aperture of the core of the first length of optical fiber. At least one of the lengths comprises an active material that can provide light having the wavelength of operation via stimulated emission responsive to the optical fiber receiving pump light.

Abstract: A nano/micro-patterned optical device includes a soft film substrate and nano/micro thin wires. A surface of the soft film substrate includes a nano/micro-pattern formed through a lithography process, and the nano/micro-pattern includes a plurality of depressed grooves. The nano/micro thin wires are placed in the depressed grooves, and used to form a plurality of optical waveguides, in which the optical waveguides include at least one optical coupling region, and the optical coupling region is located on a joining position of the optical waveguides. A fabrication method of the nano/micro-patterned optical device is also provided.

Abstract: A waveguide-mode (WM) coupler having a plurality of single-mode fibers, each optically coupled to a different respective waveguide mode of a multimode fiber. The coupling optics employed by the WM coupler are scalable and include reflective fiber-tip coatings, polarization beam splitters, phase masks, and quarter-wave plates configured to overlap and/or separate the optical beams corresponding to different waveguide modes of the multimode fiber in a manner that does not cause a significant increase in the optical insertion losses with an increase in the number of optical channels in the WM coupler.

Abstract: A termination for an optical fiber is disclosed, including an end cap optically connected to a delivery end of the fiber and tapering its towards its proximal end so as to expand the signal beam output by the fiber, a capillary having a bore mounted so that the end cap and an end portion of the delivery fiber are mounted within the bore, the capillary having an end which is angled so as to reflect undesired radiation within the capillary away from the fiber, and a cladding mode stripper arranged upstream of the delivery end.

Abstract: A compact monostatic optical transmitter/receiver device simultaneously transmits an optical beam and collects returning light using a single lens or optical aperture. The system provides automatic alignment of the transmit and receive aperture and is compatible with fiber-coupled laser sources. Transmit light is emitted from a double-cladding fiber core while received light is coupled into the inner cladding of the same fiber. The transmit light propagating in the core and the received light propagating in the inner cladding are separated by the means of a diplexer comprised of a fused fiber coupler or a fiber-coupled micro-optic device.

Abstract: A device for cooling optical components based on optical fibers for transmitting high optical power. The device includes one or more cavities with a flowing coolant to take care of optical power loss. The device includes a transmitting construction material having a low heat expansion coefficient arranged in direct connection with the optical components and arranged to transmit power loss radiation into the cavity which is flushed with the flowing coolant. The transmitting construction material is made as a transparent tube and surrounded by a tubular casing of a non-transparent material having a good absorption capacity so that the cavity is formed between the two materials.

Abstract: A system configured to generate an optical beam from a fiber laser is presented. The system includes a fiber gain medium having a core and a cladding, the core being configured to convert radiation from a pump beam into an output beam, the cladding having a mode propagating section and a mode stripping section bounded on a near end and a distal end by the mode propagating section, the mode stripping section of the cladding being configured to scatter excess pump radiation received from the mode propagating section in a substantially outwardly radial direction. The system also includes a rigid support member into which the fiber gain medium is placed, the rigid support member completely encompassing the mode stripping section of the cladding and joined to the fiber at the mode propagating section of the cladding.

Abstract: A waveguide and resonator are formed on a lower cladding of a thermo optic device, each having a formation height that is substantially equal. Thereafter, the formation height of the waveguide is attenuated. In this manner, the aspect ratio as between the waveguide and resonator in an area where the waveguide and resonator front or face one another decreases (in comparison to the prior art) thereby restoring the synchronicity between the waveguide and the grating and allowing higher bandwidth configurations to be used. The waveguide attenuation is achieved by photomasking and etching the waveguide after the resonator and waveguide are formed. In one embodiment the photomasking and etching is performed after deposition of the upper cladding. In another, it is performed before the deposition. Thermo optic devices, thermo optic packages and fiber optic systems having these waveguides are also taught.

Abstract: A double clad fiber includes a core, a first cladding provided so as to cover the core, and a second cladding provided so as to cover the first cladding. The second cladding has a plurality of pores extending in a length direction and arranged so as to surround the first cladding. In at least one fiber end, the second cladding has been removed by mechanical processing so that the at least one fiber end is formed by the core and the first cladding.

Abstract: A waveguide has a core through which laser light can propagate in a TM mode, that has a rectangular cross section perpendicular to a propagative direction of the laser light, and through which the laser light can propagate in a fundamental mode in which only one portion exists on the cross section of the core where a light intensity of the laser light becomes maximal, and a higher order mode in which two or more portions exist where the light intensity becomes maximal, a clad surrounding the core, and a light absorbing element in the clad, and wherein a distance between the light absorbing element and the core is shorter than a penetration length of evanescent light in the higher order mode, but is longer than a penetration length of evanescent light in the fundamental mode.

Abstract: A cladding mode stripper for stripping cladding modes from an optical fiber is disclosed. The cladding mode stripper includes a reflective base and a block of a transparent material disposed on the reflective base. The block of the transparent material has a groove in its bottom surface for the fiber. The fiber is thermally coupled to the base and optically coupled to the groove in the block, for example using an index matching gel. The cladding mode light is reflected from the reflective base and is absorbed in a cover enclosing the block. An additional thin block of transparent heat-conductive material can be placed between the fiber and the reflective base, to prevent the index matching gel from contacting the reflective surface of the base.

Abstract: Optical fiber lasers and components for optical fiber laser. An optical fiber laser can comprise a fiber laser cavity having a wavelength of operation at which the cavity provides output light, the cavity including optical fiber that guides light having the wavelength of operation, the fiber having first and second lengths, the first length having a core having a V-number at the wavelength of operation and a numerical aperture, the second length having a core that is multimode at the wavelength of operation and that has a V-number that is greater than the V-number of the core of the first length optical fiber at the wavelength of operation and a numerical aperture that is less than the numerical aperture of the core of the first length of optical fiber. At least one of the lengths comprises an active material that can provide light having the wavelength of operation via stimulated emission responsive to the optical fiber receiving pump light.

Abstract: A phase modulation waveguide structure includes one of a semiconductor and a semiconductor-on-insulator substrate, a doped semiconductor layer formed over the one of a semiconductor and a semiconductor-on-insulator substrate, the doped semiconductor portion including a waveguide rib protruding from a surface thereof not in contact with the one of a semiconductor and a semiconductor-on-insulator substrate, and an electrical contact on top of the waveguide rib. The electrical contact is formed of a material with an optical refractive index close to that of a surrounding oxide layer that surrounds the waveguide rib and the electrical contact and lower than the optical refractive index of the doped semiconductor layer. During propagation of an optical mode within the waveguide structure, the electrical contact isolates the optical mode between the doped semiconductor layer and a metal electrode contact on top of the electrical contact.

Abstract: An optical device includes a first waveguide having an end portion configured to receive an optical signal, the optical signal having a fundamental mode; a second waveguide having an end portion spaced from the end portion of the first waveguide; and a cladding layer surrounding the first and second waveguides. The first waveguide is configured such that the optical signal undergoes multimode interference to focus the fundamental mode at the end portion of the second waveguide.

Abstract: A package for dissipating heat power and/or optical power from an optical fiber component of a device is provided. The package includes a heat sink packaging receptacle for accommodating the optical fiber component having a cavity for receiving a temperature sensitive portion of the optical fiber component. According to one aspect, the package may include a power-dissipative material for dissipating heat power or optical power, the power-dissipative material extending within the cavity and surrounding the temperature-sensitive portion of the optical fiber component. According to another aspect, the package may include at least one channel extending between the cavity and an end of the heat sink packaging receptacle, the channel being in intimate contact with the cladding of the optical fiber component for dissipating heat power and/or optical power from the optical fiber component.

Abstract: A light collector is provided to converge light from a light source down to a range of acceptance angles of an illumination optic, and to couple the converged light into the illumination optic, where the range of acceptance angles of the illumination optic is less than a range of emission angles of the light source.

Abstract: A system for coupling light into a fiber in accordance with embodiments of the present invention include a first fiber, a second fiber which is a double clad fiber, and a bulk optic component positioned between the first and second fibers. At least one mode stripper is positioned between the first fiber entry port and the second fiber exit port providing for limiting and removal of propagating clad light.

Abstract: A low-loss optical interconnect is disclosed and may include an optical interconnect system with narrow and wide waveguides joining optical devices. The system may also comprise mode converters and waveguide bends. The waveguides may be made of silicon. Other exemplary aspects of the invention may comprise a continuous optical bend, whose radius of curvature at its endpoints is infinity and at its internal points is finite. The bend may be made of silicon. The width of the bend may vary along the bend. The system may comprise narrow and wide waveguides and a continuous bend.

Abstract: Apparatus comprising a source of optical radiation (15), an optical fibre (1), and an absorbing material (2), wherein; the optical fibre (1) comprises a core (37), at least one cladding (38), and an optical surface (3); the source of optical radiation (15) provides optical radiation (16) that propagates along the core (37) of the optical fibre (1), and unwanted optical radiation (14) that propagates along the cladding (38) that surrounds the core (37); and the absorbing material (2) is in contact with the optical surface (3) over a length (5) of the optical fibre (1).

Abstract: A powerful fiber laser system is configured with at least one gain block. The gain block includes an input fiber guiding a pump light, a multiclad active fiber receiving the pump light so that a major portion is absorbed in the core of the active fiber while a minor portion of the pump light propagates in the inner cladding of the active fiber, and a multiclad output fiber. The multiclad output fiber is configured with a core, guiding a signal lased by the core of the active fiber upon absorption of the major portion of the pump light, an inner cladding receiving the minor portion of the pump light and an outer cladding. The inner and outer claddings of the multiclad output fiber have respective refractive indexes which are selected so that the refractive index of the outer cladding is higher than that one of the inner cladding.

Abstract: An optical waveguide device including a dielectric substrate and a folded waveguide formed on the substrate, including a first waveguide and a second waveguide, one part of the first waveguide being connected to one end of the second waveguide at a first coupling portion, the other end of the second waveguide connected to another part of the first waveguide at a second coupling portion, the first waveguide being straight or curved with a radius of curvature larger than or equal to a first curvature radius, and the second waveguide being straight or curved with a radius of curvature smaller than the first curvature radius. An outer groove is formed on the substrate along an outer peripheral of the folded waveguide, an input-side inner groove is formed on the substrate near a first coupling portion, and an output-side inner groove is formed on the substrate near a second coupling portion.

Abstract: The strain-managed optical waveguide assemblies of the present invention utilize a large-mode-area (LMA) optical fiber that is annealed in a first bending such that the fiber in that configuration has substantially no axial strain. A fiber support member is then used to support the annealed LMA optical fiber in a second bending configuration that forms within the LMA optical fiber an axial strain profile that reduces stimulated Brillouin scattering (SBS) as compared to the first bending configuration, and that also preferably causes the LMA optical fiber to operate in a single mode. The LMA optical fiber may have a double-clad configuration and include a doped core that serves as a gain medium. The strain-managed optical waveguide assembly can then be used to constitute a fiber amplifier that mitigates the SBS penalty associated with high-power fiber-based optical systems.

Abstract: A composite waveguide includes a central core configured to transmit a plurality of modes and at least one side core helically wound about the central core and configured to be selectively coupled to at least a portion of the plurality of modes in the central core.

Abstract: A method of coupling a waveguide to a multi-layered active device structure on a substrate is described. The method includes forming a junction area by etching the active device structure to form a sloped etch profile with respect to the substrate, aligning multiple layers of the multi-layered active device structure via an etch stop adjacent the multi-layered active device structure, and depositing the waveguide over the etched active device structure, wherein a sloped active passive junction is formed at the junction area that reduces residual interface reflection in a resulting coupled device. Also described is a method for removing at least one laser layer in a sloped junction region forming passive amorphous silicon waveguides. This includes depositing a SiN layer for use as an etch mask, patterning a photoresist mask, patterning the SiN layer by reactive ion etching, stripping the photoresist mask, and etching the at least one laser layer.

Abstract: An optical fiber contact for transmitting moderate-magnitude optical power. The fiber contact includes an optical fiber having an inner core and a surrounding cladding for transmitting the radiation in the core. Additional surrounding layers including so-called buffer and jackets mechanically stabilize the optical fiber. The forward part of the optical fiber contact is surrounded by a transparent tubular member. The tubular member extends a certain length along the outer cylindrical surface of the cladding. There is no heating by power loss radiation, as the power loss radiation is leaving the contact as optical radiation. To disperse radiation propagating within the cladding, the cladding includes a roughening or additional layers of a transparent material. In case of additional layers of transparent material then the outermost layer should be roughened.

Abstract: An optical device (D) is dedicated to the transformation of the propagation mode of optical signals. This device comprises at least a first mode converter (3) that is supplied with signals that are propagated in a first guided mode and that delivers the signals in a multimode fibre (4) partly in the first guided mode and partly in a second guided more of a higher order that the first. The multimode fibre (4) comprises at least first passive filtering means (R) which have the task of converting the first guided mode into at least one dissipative cladding mode in order to prevent or limit the propagation of the signals in this first guided mode while at the same time authorising the propagation of the signals having the second guided mode in the multimode fibre (4).

Abstract: A termination for an optical fibre is disclosed, including an end cap optically connected to a delivery end of the fibre and tapering its towards its proximal end so as to expand the signal beam output by the fibre, a capillary having a bore mounted so that the end cap and an end portion of the delivery fibre are mounted within the bore, the capillary having an end which is angled so as to reflect undesired radiation within the capillary away from the fibre, and a cladding mode stripper arranged upstream of the delivery end.

Abstract: A fiber stub assembly is provided that has a cladding layer that is reduced in diameter near the end of the stub into which light is launched from a light source. The portion of the stub having the cladding layer with the reduced diameter is surrounded by a light-absorbing material that is in contact with the inner surface of the ferule and with the outer surface of the cladding layer. The light-absorbing material and the outer surface of the cladding layer have indices of refraction that are matched, or very close to one another, such that any modes of light that are propagating in the cladding layer that impinge on the interface propagate into the light-absorbing material and are absorbed thereby. The reduced diameter of the cladding layer and the surrounding light-absorbing material form a pin hole opening through which light is received.

Abstract: An optical device is disclosed. The device comprises a waveguide formed within a substrate; and at least one semitransparent mirror structure formed within the waveguide and being designed and constructed to partially reflect light propagating in the waveguide such that a portion of the light is emitted through the surface of the waveguide. The semitransparent mirror structure(s) is capable of reflecting light while substantially preserving the shape of the light profile in the waveguide.

Abstract: The present disclosure provides an approach to more efficiently amplify signals by matching either the gain materials or the pump profile with the signal profile for a higher-order mode (HOM) signal. By doing so, more efficient energy extraction is achieved.

Abstract: The subject invention pertains to a method and apparatus for multiplexing in optical fiber communications. The subject invention relates to a method and apparatus for spatial domain modulation in optical wavelengths. In a specific embodiment, the subject invention relates to a spatial domain multiplexer (SDM) for use with an optical fiber. Preferably, the input channels coupled into the fiber optic cable include collimated laser beams. The techniques of the subject invention can be utilized with single mode and multi mode waveguide structures, for example, single mode and multi mode optical fibers. The subject invention is applicable to step index optical fiber and to graded index optical fiber. Applications of the subject technology can include secure data links, for example, which can modulate data such that if the data is intercepted, the data cannot be interpreted. The subject methods and apparatus can also be used in conjunction with other multiplexing techniques such as time-domain multiplexing.

Abstract: Whispering-gallery-mode (WGM) optical resonators made of crystal materials to achieve high quality factors at or above 1010.

Abstract: A communications coupling for a low bandwidth fiber optic cable and a high bandwidth fiber optic cable, includes: a guiding ferrule adapted for coupling to a surrogate fiber optic cable comprised of one of the low bandwidth fiber optic cable and the high bandwidth fiber optic cable, the guiding ferrule including at least one mounting feature for aligning the guiding ferrule with an optical axis of the surrogate cable; the guiding ferrule further including at least one guiding feature for aligning the optical axis of the surrogate fiber optic cable with an optical axis of a connecting fiber optic cable, the connecting fiber optic cable comprised of the other one of the low bandwidth fiber optic cable and the high bandwidth fiber optic cable. A method and a communications infrastructure are provided.

Abstract: In an MMI device with which a plurality of narrow width single-mode waveguides are provided at both ends of a multimode waveguide M, and light introduced into one single-mode waveguide on the input side is interfered in the multimode waveguide to be emitted from two single-mode waveguides on the output side, a wall face perpendicular to the optical axis direction that is not provided with a single-mode waveguide is formed with an inclination being given in the thickness direction, at both ends of the multimode waveguide. Thereby, the light which is incident on the wall face is reflected toward the substrate side. In this case, because the angle of incidence into the substrate is small, almost all of the light is radiated into the inside of the substrate without being returned to the single-mode waveguide on the incident side. Therefore, an MMI device which is capable of completely eliminating the return of the reflected light with a simple structure, and a manufacturing method for the same are provided.

Abstract: A waveguide receiving light which propagates through free space is configured with a coupler and delivery fiber. The coupler, including a GREEN or multimode fiber, has a protective coating and so does the delivery fiber. Upon splicing of the coupler to the delivery fiber, the protective coatings of the respective coupler and delivery fiber are spaced apart exposing thus end regions of the respective coupler and fiber. The exposed regions are covered by a light stripper made of material having a refractive index which is substantially the same as or greater than that one of outer claddings. Accordingly, the light stripper minimizes the amount of light capable of coupling into the protective coatings of the respective delivery and coupler fibers enhancing thus a power handling capabilities of the waveguide.

Abstract: A method of fabricating a passive polarization sorter includes the steps of providing first and second waveguides. The first waveguide has an input and an output. The first waveguide supporting at least one guided TE polarized mode of mode ranking mode-i-TE and at least one guided TM polarized mode of mode ranking mode-j-TM. The second waveguide is positioned adjacent to the first waveguide, and the first and second waveguides are shaped to form an adiabatic region in which light having one of the TE and TM polarized modes remains within the first waveguide, and light having the other one of the TE and TM polarized modes evanescently couples into the second waveguide.

Abstract: An optical fiber mode coupling device, capable of being readily connected to a conventional optical fiber with a high degree of ruggedness, is provided. The inventive mode coupling device only allows transmission of at least one supported fiber mode therethrough, and is preferably configured to maximize the coupling, of at least one desired fiber mode, to the at least one supported fiber mode. Advantageously, the inventive mode coupling device is capable of performing the functions of a mode filter for the signal entering its first end, or serving as a mode conditioner for the signal entering its opposite second end.

Abstract: The present invention concerns an optical fiber acting as a slab-coupled waveguide. The optical fiber has a cross-section comprising a core (1), which is two dimensional and responsible for the horizontal confinement of the fiber's fundamental mode. A slab (2) is placed in the vicinity of the core (1). The slab (2) extends substantially in a plane, acts as a mode sink for the core, and is at least three times wider than the core (1). A cladding (3) surrounds the core (1) and the slab (2). The cladding (3) is made of one or several materials with refractive indices lower than the core and slab materials. The core (1), slab (2) and cladding (3) and any other protective or supportive structures attached to them form an overall structure that determines the mechanical properties of the fiber. The cross-section of the fiber is formed to make the fiber significantly more flexible in the direction perpendicular to the plane of the slab than in the plane of the slab.

Abstract: A system is disclosed. The system includes an optical waveguide; and an optical transmitter coupled to the optical waveguide. The transmitter includes a optical relay to condition a launch of an optical beam into the optical waveguide to minimize a number of optical modes launched into the optical waveguide.

Abstract: A method of using a passive polarization sorter comprising the step of deploying a first waveguide and a second waveguide forming an adiabatic region along a portion of their length. Then, an input optical signal is introduced into the first waveguide wherein light having at least one guided TE polarized mode of mode ranking mode-i-TE and at least one guided TM polarized mode of mode ranking mode-j-TM remaining within the first waveguide. Light having the other one of the TE and TM polarized modes is evanescently coupled into the second waveguide in the adiabatic region.

Abstract: A method of filtering optical signals (300) utilizing an optical fiber (100A-100D). The method of filtering optical signals (300) includes the steps (304) selecting an optical fiber (100A-100D) coupled to a source of optical signals, (306) disposing a core (102) in the bore (103) of the optical fiber (100A-100D) formed of a core material (105), (308) selecting a core material (105) to provide a waveguide within the optical fiber (100A-100D), (310) disposing an optical grating (114-1) in a first optical cladding layer (104) disposed about the core (102), (312) propagating an optical signal within the optical fiber (100A-100D) guided substantially within the core (102), (314) modifying a propagation path of selected wavelengths comprising said optical signal with the optical grating (114-1), and (316) determining selected wavelengths for which the propagation path is modified by selectively varying an energetic stimulus to the core (102) thereby tuning the waveguide.

Abstract: Whispering-gallery-mode (WGM) resonators configured to support only a single whispering gallery mode.

Abstract: A composite waveguide comprising a central core and at least one side core helically wound about said central core and in optical proximity to said central core.

Abstract: An optical communication system includes a transmitter that receives an input optical signal from an optical source and performs filtering so that an output signal from the transmitter includes a specific set of fiber modes that are allowed to pass for further processing. A receiver receives the output signal and performs the necessary operations to retrieve a signal indicative of the input signal.

Abstract: A higher order mode dispersion compensating fiber includes an optical fiber and a first loss layer which is provided within the fiber and which attenuates a lower order mode propagating through the optical fiber while not attenuating a higher order mode which is higher than the lower order mode. A dispersion compensating fiber mode converter for a higher order fiber includes a single mode fiber; a higher order mode dispersion compensating fiber; and a fused and extended portion which has been formed by fusing and extending the single mode fiber and the higher order mode fiber. The fused and extended portion converts between the LP01 mode of the single mode fiber and the LP02 mode of the higher order mode dispersion compensating fiber.