Abstract: This invention provides an optical device comprising a large group of non-uniform resonators operating cumulatively as a ‘super-ring’ to provide a controllable group delay with large bandwidth. The super-ring tuning is performed by a single control. The device may include two super-rings, each includes a large number of resonators with a resonant frequencies centered around ?1 and ?2 respectively. The invention provides multiple ways to improve the delay duration, bandwidth and the tuning speed, and overcomes the issue of non-uniformity of resonance frequency for devices incorporating multiple optical resonators.

Abstract: To efficiently apply jitter to an optical signal using a simple configuration, provided is an optical signal output apparatus that outputs an optical pulse pattern signal including jitter, the optical signal generating apparatus comprising a light source section that outputs an optical signal having an optical frequency corresponding to a frequency control signal; an optical modulation section that modulates the optical signal output by the light source section, according to a designated pulse pattern; and an optical jitter generating section that delays an optical signal passed by the optical modulation section according to the optical frequency, to apply jitter to the optical signal.

Abstract: Some embodiments of the disclosed subject matter provide systems, devices, and methods for tuning resonant wavelengths of an optical resonator. Some embodiments of the disclosed subject matter provide systems, devices, and methods for tuning dispersion properties of photonic crystal waveguides. In some embodiments, methods for tuning a resonant wavelength of an optical resonator are provided, the methods including: providing an optical resonator having a surface; determining an initial resonant wavelength emitted by the optical resonator in response to an electromagnetic radiation input; determining a number of layers of dielectric material based on a difference between the initial resonant wavelength and a target resonant wavelength and a predetermined tuning characteristic; and applying the determined number of layers of dielectric material to the surface of the optical resonator to tune the initial resonant wavelength to a tuned resonant wavelength.

Abstract: A wavelength filter includes a first waveguide with a transmission band of a predetermined basic mode and a second waveguide, arranged in at least one location of the first waveguide, with a transmission band whose cutoff frequency corresponds to a finite value included in the transmission band of the basic mode. A pair of optical couplers constituting a Mach-Zehnder interferometer is connected to the opposite ends of a filter unit including the first waveguide and the second waveguide. When a plurality of wavelength filters is cascaded, the wavelength filters can be each varied in terms of the cutoff frequency of the second waveguide.

Abstract: The present invention relates to a light source apparatus. The light source apparatus has an MOPA configuration and comprises a seed light source, a pulse generator, an intermediate optical amplifier, a final stage optical amplifier, a delivery optical fiber, and a light output terminal. The delivery optical fiber is a PBG fiber having a photonic bandgap (PBG) structure in a core-surrounding portion located around the core. Light with a wavelength in a high loss band of the PBG fiber is inputted into the PBG fiber.

Abstract: The invention relates to a photonic crystal four-port circulator based on the coupling of magneto-optical cavities, which comprises two same magneto-optical cavities and three waveguides which are symmetrically distributed on the periphery of each magneto-optical cavity, wherein two waveguides connected with the magneto-optical cavities respectively are in a “v-shaped” arrangement, thereby guaranteeing that waveguides which are connected with the left sides of the two magneto-optical cavities are parallel to each other and waveguides which are connected with the right sides of the two magneto-optical cavities are parallel to each other as well and achieving the high-efficiency transmission in the case of the coupling of the magneto-optical cavities.

Abstract: A microstructured optical fiber for generating broadband white light having a core doped with germanium and silica cladding surrounding the core, the cladding including a plurality of holes arranged in the form of a regular mesh, wherein the diameter F of a hole in the cladding, the pitch L between the respective centers of two neighboring holes in the cladding, and the refractive index difference Dn between the germanium-doped fiber core and the silica of the cladding are such that the fiber can generate white light on the fundamental mode over a wavelength band having a width of at least 1000 nm.

Abstract: An apparatus comprising a Mache-Zehnder interferometer. The Mache-Zehnder interferometer comprises: a 1×2 optical splitter having an optical input, a 2×2 optical coupler having first and second optical outputs, two optical waveguide arms end-connecting each optical output of the 1×2 optical splitter to a corresponding optical input of the 2×2 optical coupler, a variable optical phase shifter on one of the waveguide arms and a plurality of optical resonators, each optical resonator being controllably coupled along one of the optical waveguide arms. An optical path length between the optical input of the 1×2 optical coupler and the first optical output of the 2×2 optical coupler is substantially the same via the first optical waveguide arm and the second optical waveguide arm when the optical resonators are decoupled from the optical waveguide arms.

Abstract: Taught is a photonic crystal three-port circulator, which comprises a dielectric background material and a plurality of first air columns which are symmetrically arranged in the form of triangular lattice in the dielectric background material. The photonic crystal three-port circulator also comprises a magneto-optical cavity and three waveguides, wherein the magneto-optical cavity is arranged at the center of the photonic crystal three-port circulator; the three waveguides are symmetrically distributed around the magneto-optical cavity; and each waveguide comprises a waveguide port which is arranged at the position in the waveguide far away from the magneto-optical cavity. The photonic crystal three-port circulator realizes circular light transmission in single rotational direction from any one of the waveguide ports to another next to it, has a simple and compact structure, and can be easily integrated with other photonic crystal devices.

Abstract: A transmission system is provided with a transmission apparatus that outputs an ASE light from a transmission light amplifier and with a reception apparatus provided with: a tilt detection unit that detects the optical strength levels of at least two probe lights having different wavelengths from a received ASE light; and a reception light amplifier that performs a first-order tilt correction on light to be output in a linear manner so as to reduce the difference in the optical strength level of the two probe lights detected by the tilt detection unit.

Abstract: The present invention describes a microresonator that can be used as a 1:f variable coupler in a unit cell. It is described how a cascade of unit cells can be used to form a tunable, higher-order RF-filter with reconfigurable passbands. The disclosed filter structure can be utilized for the narrowband channelization of RF signals that have been modulated onto optical carriers. It is also disclosed how to utilize add/drop capabilities of the contemplated microdisks to confer connectivity and cascading in two dimensions. The present invention can conveniently provide a wavelength division multiplexing router, where an array of unit cells as provided herein can form a programmable optical switching matrix, through electronic programming of filter parameters.

Abstract: Apparatus and method for in-line cladding-light dissipation including forming a light-scattering surface on the optical fiber such that the light-scattering surface scatters cladding light away from the optical fiber. In some embodiments, the apparatus includes an optical fiber having a core and a first cladding layer that surrounds the core, wherein a first portion of the optical fiber has a light-scattering exterior surface. Some embodiments further include a transparent enclosure, wherein the transparent enclosure includes an opening that extends from a first end of the transparent enclosure to a second end of the transparent enclosure, and wherein at least the first portion of the optical fiber is located within the opening of the transparent enclosure. Some embodiments include a light-absorbing housing that surrounds the optical fiber and the transparent enclosure and is configured to absorb the light scattered away from the optical fiber by the light-scattering exterior surface.

Abstract: Multimode optical fiber systems with adjustable chromatic modal dispersion compensation are disclosed, wherein the system includes a VCSEL light source and primary and secondary optically coupled multimode optical fibers. Because the VCSEL light source has a wavelength spectrum that radially varies, its use with the primary multimode optical fiber creates chromatic modal dispersion that reduces bandwidth. The compensating multimode optical fiber is designed to have a difference in alpha parameter relative to the primary multimode optical fiber of ?0.1?????0.9. This serves to create a modal delay opposite to the chromatic modal dispersion. The compensation is achieved by using a select length of the compensating multimode optical fiber optically coupled to an output end of the primary multimode optical fiber. The compensating multimode optical fiber can be configured to be bend insensitive.

Abstract: An optical wavelength filter has optical waveguides each of which includes a cladding layer and a core having a refractive index that is as high as that of the cladding layer by a factor of 1.4 or more. Each optical waveguide is partitioned into a reference section providing a reference and an adjustment section for adjusting phase differences. The reference section of each optical waveguide is so set that the optical waveguide in this section has a first equivalent refractive index and a first length. The adjustment section is so set that the waveguide in this adjustment section has a second equivalent refractive index and a second length. Two waves of light outputted from the output ends of adjacent two of the optical waveguides interfere with each other with a predetermined phase difference, thereby accomplishing independency of temperature and dimensional error.

Abstract: Certain embodiments of the invention may include an optical fiber modules encapsulated by flame retardant encapsulant. According to an example embodiment of the invention, an optical fiber module is provided. The optical fiber module comprises an optical fiber shaped to form one or more loops within the module, and a flame retardant encapsulant covering any exposed portion of the optical fiber. The flame retardant encapsulant is rated UL94 V-1 or better. The loop portion of the optical fiber may be affixed permanently within the module and any exposed surface of the fiber is coated with the encapsulant.

Abstract: When phases of lights passing through arms are adjusted, a first DC bias and a first modulation signal are applied to one arm from one modulating electrode, and a second DC bias and a second modulation signal are applied to the other arm from the other modulating electrode. The first and second DC biases are applied to the modulating electrodes such that a rate of a product of a length of one modulating electrode and the first DC bias and a product of a length of the other modulating electrode and the second DC bias is kept at a constant value. According to this constitution, it is possible to enable an optimum control of a phase difference between the arms and a precise control of wavelength chirp characteristics with a simple element constitution, and an optical modulation of which device size is small and having fine characteristics is enabled.

Abstract: An in-line optical device adapted to be bonded in between ends of an optical fiber line is disclosed. The in-line optical device has an inner optical field interaction region, an outer support structure, and at least one radial opening. In some embodiments, a void region substantially surrounds the inner optical field interaction region. Systems including the in-line optical device and methods of making and using the in-line optical device are provided. Numerous other aspects are provided.

Abstract: The present invention relates to a higher-order dispersion compensation device (210), the device being adapted to cooperate with a pair of optical components (P1, P2), e.g. a pair of prisms, being arranged to compensate first-order dispersion by separating different wavelengths spatially. The compensation device (210) has the form of a phase plate, wherein the phase change for each wavelength is adjusted by designing the height (h) at the corresponding position (x) of the plate so as to substantially compensate for higher-order dispersion. The invention is advantageous for obtaining a higher-order dispersion compensation device which is relatively simple to construct and use making it a quite cost-effective device. The invention also relates to a corresponding optical system and method for compensating dispersion where this is important, e.g. in a multiple-photon imaging system.

Abstract: A waveguide intersection includes an input waveguide and an output waveguide; a crossing waveguide intersecting the input waveguide and the output waveguide to form an intersection; and a block that is optically joined to the intersection such that a guided mode is produced within the intersection. A method of reducing optical losses within a waveguide intersection includes increasing a cross-sectional height of an intersection such that optical energy passing through the intersection is laterally confined.

Abstract: The invention relates to an optical fiber employable in an optical communication system using Raman amplification and adapted to improve OSNR and suppress bending loss at the same time, and the like. The optical fiber is a silica-based optical fiber having a depressed refractive index profile constituted by at least a core, an inner cladding having a low refractive index, and an outer cladding, an effective area Aeff of 110 ?m2 or more at the wavelength of 1550 nm, and a fiber cutoff wavelength ?c of 1.3 ?m or more but 1.53 ?m or less. The depressed refractive index profile is designed such that the ratio Ra(=2b/2a) of the diameter of the inner cladding to the diameter of the core is 2.5 or more but 3.5 or less and that the relative refractive index difference ?? of the inner cladding with respect to the outer cladding is at least the relative refractive index difference ??min where the bending loss at the wavelength for use is minimized but not exceeding (??min+0.06) %.

Abstract: The present invention provides an optical 90-degree hybrid circuit for reducing wavelength dependency of an IQ phase difference. An optical 90-degree hybrid circuit according to the present invention comprises a first demultiplexing optical coupler including a first and second input port, a second demultiplexing optical coupler including a third and fourth input port, first and second arm waveguides connected to the first and second input port, each having the same length, a third and fourth arm waveguides connected to the third and fourth input port, each having the same length, a 90-degree phase shift section installed in one of the first to fourth arm waveguides, a first optical coupler connected to the first and third arm waveguide, and a second optical coupler connected to the second and fourth arm waveguide, the light is inputted into the first and fourth input port or into the second and third input port.

Abstract: A method for predicting an optical fiber performance parameter includes measuring N values for the optical fiber performance parameter at N stages during manufacture or installation of a first optical fiber, where N is an integer. A first set of correlation values is generated representing shifts in the measured optical fiber performance parameter values at the N stages. An installed value of the optical fiber performance parameter is estimated for a second optical fiber based on the first set of generated correlation values and at least one measured optical fiber performance parameter value associated with the second optical fiber.

Abstract: A method for predicting polarization mode dispersion (PMD) in an installed optical fiber. Values of PMD are measured for a first optical fiber at various points in time during the manufacture and installation of the first optical fiber. Values of PMD are identified that correspond to sensitive ones of the various points in time. A set of correlation coefficients is calculated based on the values of PMD corresponding to the sensitive ones of the various points in time. An installed value of PMD for a second optical fiber is predicted based on the set of correlation coefficients.

Abstract: Coupled-resonator optical waveguides (CROW) can be used to control a speed of an optical signal. In particular, the coupling distance between the resonators can be adjusted to precisely control a group delay of an optical wave. Systems and methods are described to control such coupling distance in a CROW.

Abstract: An apparatus for forming laser radiation. The apparatus can form the laser radiation such that the laser radiation can enter an optical fiber. The apparatus contains a first lens device for deflection and/or imaging or collimation of the laser radiation with respect to a first direction, and a second lens device for deflection and/or imaging or collimation of the laser radiation with respect to a second direction. The first and the second lens devices are provided in or on a component.

Abstract: The wavelength control device comprises a first Mach-Zehnder filter which receives a first optical signal and outputs an optical signal having a predetermined wavelength, a second Mach-Zehnder filter which receives a second optical signal and outputs an optical signal having a predetermined wavelength, a heating unit heating respective parts of either one of the waveguides of the first and second Mach-Zehnder filters, a first wavelength detecting unit which receives an optical signal from the first Mach-Zehnder filter and detects a wavelength thereof, a second wavelength detecting unit which receives an optical signal from the second Mach-Zehnder filter and detects a wavelength thereof, a power control unit which controls power supplied to the heating unit based on the wavelength received from the first wavelength detecting unit, and an output unit which outputs a wavelength value based on the wavelength received from the second wavelength detecting unit.

Abstract: An array reflector comprising a waveguide and a high reflectivity mirror is disclosed. The waveguide has an input end and a reflective end. The high reflectivity mirror is disposed at the reflective end. The array reflector also includes n?1 mirrors arrayed along the length of the waveguide, wherein n is an integer greater than two.

Abstract: A light guide device includes a light guide plate, a diffusion layer, and a brightening layer. The light guide plate includes a first surface, a second surface opposite to the first surface, and diffusion pots positioned on the first surface. The diffusion layer is adhered to the second surface of the light guide plate, and includes transparent adhesive and diffusion particles scattered in the transparent adhesive. The brightening layer is adhered to the diffusion layer, and includes a micro structure formed on a surface of the brightening layer facing away from the diffusion layer. The micro structure includes a number of cutouts. A manufacturing method for the light guide device is also provided.

Abstract: A waveguide system includes a first waveguide having surface roughness along at least one surface and a second waveguide substantially identical to the first waveguide and having substantially identical surface roughness along a corresponding side. The first and second waveguides are separated from each other by a predetermined distance and are configured to receive respective first and second light signals having antisymmetric modes. The predetermined distance between the first and second waveguide tends to cause cancellation of at least far-field polarization radiation emanating from the first and second waveguides and resulting from the surface roughness.

Abstract: An efficient grating coupler for a semiconductor optical mode includes a tapered edge to couple light between waveguide modes constrained by differing waveguide thicknesses. An optical circuit or laser has a waveguide in a rib or strip waveguide section that is of different height (e.g., having different vertical constraints) than a waveguide section that has a grating coupler through which light passes off-circuit. The tapered edge can couple light between the two waveguide sections with very low loss and back-reflection. The low loss and minimal back-reflection enables testing of the photonics circuit on a wafer level, and improved performance through the grating coupler.

Abstract: An image reading apparatus includes a light guide arranged between a light source and a document. The light guide has a light incident surface at a side of the light source, light from the light source, is incident, a first light emitting surface at a side of the document, a second light emitting surface different from the first light emitting surface, a first reflecting surface between the first and second light emitting surfaces, a second reflecting surface between the light incident surface and the second light emitting surface, and a third reflecting surface facing the second reflecting surface. The first reflecting surface reflects light toward the first light emitting surface. The second reflecting surface reflects light toward one of the second light emitting surface and the first and third reflecting surfaces. The third reflecting surface reflects light toward the second light emitting surface or the first reflecting surface.

Abstract: A system (10) and methods (800, 900) for routing optical signals are disclosed. The system includes a large core hollow waveguide (30) having a reflective coating (40) covering an interior surface (32) of the hollow waveguide configured to guide a light beam (104). At least one area based beam splitter (50) is integrally formed with the hollow waveguide and has an angled reflective surface (52) with a selectable height (H) relative to the interior surface. The angled reflective surface is oriented to redirect a predetermined amount of the light beam (114) based on the height of the angled reflective surface.

Abstract: In order to provide a spot size converter and a method for making the same which enable the optical connection with low loss and are able to reduce the excess loss for the position misalignment in mounting, a spot size converter according to an exemplary aspect of the present invention includes: a substrate on which an optical waveguide including a first core is laminated and which includes a notch; a core reducing part which is formed so that a cross-section area of the first core may gradually decrease toward an end part of the first core in the direction of light propagation; a second core which surrounds the core reducing part and is made of a material whose refractive index is smaller than that of the first core; a peripheral clad which surrounds the second core and is made of a material whose refractive index is smaller than that of the second core; and a lower clad which is formed in a lower part of the second core and includes the peripheral clad; wherein the lower clad is formed in the notch.

Abstract: A microstructure optical adapter or tip according to the present disclosure may incorporate precision micro structure optical components engaging the input or output end of light energy delivery devices for customized light delivery of the light energy. The incorporation of precision micro structure optical components in injection molded plastic or glass parts will allow for inexpensive modification of the output light while also serving to protect the end of the illumination device. The micro structure optical components may also be incorporated in an adapter to tailor the light energy to the subsequent device.

Abstract: An optical device for optically multiplexing or demultiplexing light of different predetermined wavelengths is provided, the optical device comprising at least one first waveguide (11) and at least one second waveguide (12) formed on a substrate (10), wherein the at least one first waveguide and the at least one second waveguide intersect at an intersection, comprising a diffraction grating structure (13) formed at the intersection. There exists a first wavelength or wavelength band travelling within the first waveguide (11) exciting the grating structure and being diffracted an angle corresponding to an outcoupling direction and there exists a second wavelength or wavelength band, different from the first wavelength or wavelength band, travelling within the second waveguide (12) exciting the grating structure and being diffracted at an angle corresponding to the same outcoupling direction.

Abstract: A twin fiber laser arrangement is configured with active and passive fibers supporting respective signal and pump lights and a reflective coating surrounding the fibers along a section of the arrangement. The passive fiber has regions covered by respective protective layer and coating-free regions alternating with the layer covered regions, wherein the reflective coating is configured to overlap the protective layer which shields the end of the reflective coating from high power pump light.

Abstract: An active device for dynamic control of lightwave transmission properties has at least one photonic crystal waveguide that has anti-reflection photonic crystal waveguides with gradually changed group refractive indices at both input and output side. An alternating voltage or current signal applied to two electrically conductive regions changes the refractive indices of the photonic crystal materials, introducing a certain degree of blue-shift or red-shift of the transmission spectrum of the photonic crystal waveguide. The output lightwave with frequency close to the band-edge of the photonic crystal waveguide is controlled by the input electric signal. Devices having one or more such active photonic crystal waveguides may be utilized as an electro-optic modulator, an optical switch, or a tunable optical filter.

Abstract: An optical lens of an optical connector includes alignment features for passive connection alignment. Fiber inserted into the lens is aligned with a fiber groove that restricts motion in at least one direction to align the fiber. The lens includes an alignment feature to passively align the lens with a mating alignment feature of a mating connector. The groove may, for example, be L-, V-, or U-shaped. The alignment feature can be a post with corresponding recess. Alignment can further be secured with a tab that constrains pivoting of the connectors when engaged.

Abstract: A frequency-chirped nano-antenna provides efficient sub-wavelength vertical emission from a dielectric waveguide. In one example, this nano-antenna includes a set of plasmonic dipoles on the opposite side of a SiYV4 waveguide from a ground plane. The resulting structure, which is less than half a wavelength long, emits a broadband beam (e.g., >300 nm) that can be coupled into an optical fiber. In some embodiments, a diffractive optical element with unevenly shaped regions of high- and low-index dielectric material collimates the broadband beam for higher coupling efficiency. In some cases, a negative lens element between the nano-antenna and the diffractive optical element accelerates the emitted beam's divergence (and improves coupling efficiency), allowing for more compact packaging.

Abstract: A complex orthogonal code in the present invention is one in which each row of a square matrix of N rows and N columns in which an element of an mth row and nth column is exp[2?j(m?1)(n?1)/N] (where j is an imaginary unit) is adopted as a code word. An optical orthogonal code for Optical Code Division Multiplexing/Optical Code Division Multiple Access (OCDM/OCDMA) is realized by a train of N-number of optical pulses corresponding to the argument (phase) of the code elements. An optical transmitter or optical receiver includes an optical correlator provided with a sampled Bragg grating having a plurality of Bragg gratings disposed serially at regular intervals inside an optical waveguide. The optical correlator is allocated any one of the code words. In the optical transmitter, an optical signal to be transmitted is encoded by the optical correlator. In the receiver, a received optical signal is decoded by the optical correlator.

Abstract: An array reflector comprising a waveguide and a high reflectivity mirror is disclosed. The waveguide has an input end and a reflective end. The high reflectivity mirror is disposed at the reflective end. The array reflector also includes n?1 mirrors arrayed along the length of the waveguide, wherein n is an integer greater than two.

Abstract: An apparatus consisting of stacked slab waveguides whose outputs are vertically staggered is disclosed. At the input to the stacked waveguides, the entrances to each slab lie in approximately the same vertical plane. A spot which is imaged onto the input will be transformed approximately to a set of staggered rectangles at the output, without substantial loss in brightness, which staggered rectangles can serve as a convenient input to a spectroscopic apparatus. A slit mask can be added to spatially filter the outputs so as to present the desired transverse width in the plane of the spectroscopic apparatus parallel to its dispersion.

Abstract: The thermally-assisted magnetic recording head includes: a laser light source having an emission surface, the emission surface allowing laser light to be emitted therefrom; a waveguide having a core and a cladding, the core allowing the laser light emitted from the laser light source to propagate therethrough, and the cladding surrounding the core; a magnetic pole; and a plasmon generator. Each of the core and the cladding has an end surface facing the emission surface, and the end surface of the cladding suppresses returning of the laser light to the laser light source.

Abstract: An optical interconnect includes a set of splitters. Each splitter includes a source waveguide, a reflection waveguide, an output waveguide, and a partially reflective mirror element with a reflective coating. The source waveguide and the reflection waveguide are optically coupled to the partially reflective element. A photonic signal from the source waveguide is partially reflected off the reflective coating as a reflected signal into the reflection waveguide. The output waveguide is optically coupled to the opposite surface and configured such that a non-reflected portion of the photonic signal propagates into the output waveguide. The reflective coating includes a reflected surface area interfacing with the photonic signal form the source waveguide, and power of the non-reflected portion is a function of the reflective surface area interfacing with source waveguide.

Abstract: The invention provides methods and devices for generating optical pulses in one or more waveguides using a spatially scanning light source. A detection system, methods of use thereof and kits for detecting a biologically active analyte molecule are also provided. The system includes a scanning light source, a substrate comprising a plurality of waveguides and a plurality of optical sensing sites in optical communication with one or more waveguide of the substrate, a detector that is coupled to and in optical communication with the substrate, and means for spatially translating a light beam emitted from said scanning light source such that the light beam is coupled to and in optical communication with the waveguides of the substrate at some point along its scanning path. The use of a scanning light sources allows the coupling of light into the waveguides of the substrate in a simple and cost-effective manner.

Abstract: Embodiments of the invention provide a fiberoptic device that uses a gradient-index (GRIN) lens for focusing a light beam emitted by an optical fiber, but achieves a substantially longer focal length than that of a GRIN lens alone by placing a beam expander (e.g., no core fiber or step-index multimode fiber) between the terminal end of the optical fiber and the GRIN lens to simulate free space therebetween. In one embodiment, a fiberoptic device comprises an optical fiber having a fiber core and an end through which a light beam emits from the fiber core; a beam expander having a first end coupled to the end of the optical fiber and having a second end, the beam expander permitting the light beam emitting from the fiber core to pass from the first end to the second end and to expand from the first end to a larger size at the second end; and a gradient-index fiber lens coupled to the second end of the beam expander to receive the light beam from the beam expander and focus the light beam.

Abstract: A laser amplifier includes a pump source and an optically active fiber having an input portion configured to receive a signal source and an output portion. The pump source is optically coupled to the optically active fiber. The laser amplifier also includes an output fiber optically coupled to the output portion of the optically active fiber. The output fiber includes a rare-earth element. The laser amplifier further includes a beam expansion section joined to the output fiber.

Abstract: An embodiment of an apparatus includes an optical fiber for which a complete orthogonal basis of propagating modes at an optical telecommunication frequency includes ones of the propagating modes with different angular momenta. The optical fiber has a tubular optical core and an outer optical cladding in contact with and surrounding the tubular optical core. The tubular optical core has a larger refractive index than the optical cladding. The tubular optical core is configured such that those of the propagating modes whose angular momenta have the lowest magnitude for the propagating modes have substantially the same radial intensity profile.

Abstract: An apparatus includes an optical fiber having a plurality of optical cores therein. Each optical core is located lateral in the optical fiber to the remaining one or more optical cores and is able to support a number of propagating optical modes at telecommunications wavelengths. Each number is less than seventy.

Abstract: A collimator system comprises a micro lens array and a fiber array. The fiber array has a substrate with a plurality of holes for holding a plurality of optical fibers. The fibers are glued into the holes. Before gluing, each of the fibers is positioned against the same side of a corresponding hole resulting in all fibers being located substantially equally with respect to the holes. The lens array is mounted with an offset to the fiber array resulting in alignment of the fibers and the lenses.