Abstract: The present invention relates to a five-degree of freedom alignment structure 10 for an optical element 28. The alignment structure 10 is a two piece assembly including a submount 12 and a support member 18. An optical element 28 is coupled to the mounting surface 14 of submount 12. The alignment structure 10 is used to align the optical axis 34 of the optical element 28 with the optical axes 32 of another optical element 30.

Abstract: A diffraction-compensated WDM (wavelength division multiplexer) uses TTFs (thin film filters) as concave mirrors. The WDM has a plurality of filter elements for guiding the optical signal along a predetermined optical path, each filter element being transparent to a predetermined wavelength range and including compensating means for at least partially compensating for diffraction of the optical signal. Each filter element has a thin film coated on a substrate, and the compensating means is a curved surface of each thin film. The WDM is more robust than prior art WDM devices using flat TTFs.

Abstract: A multi-port fiber optic device (100) includes a pair of opposite collimators (50, 51), of which each includes a V-groove dual fiber ferrule (20, 21) with a GRIN rod lens (2, 1). At least one band-pass DWDM thin film filter (4) is securely sandwiched between the two opposite GRIN rod lens (2, 1) of the pair of collimators (20, 21). The V-groove dual fiber ferrule (20, 21) is used to couple light in and out thereof and tune the thin film filter center wavelength to the ITU grid. The light coupled in from the input fiber (13) of the V-groove dual fiber ferrule (20) will be collimated and transmitted to the DWDM thin film filter (4). The part of the in-pass-band light will pass through the filter (4) as performing a demultiplexed channel and is successively coupled into the other collimator (21) aside.

Abstract: A holographic optical element (HOE) device useable for an optical receiver system has a first element having first and second surfaces, with the first surface being positionable to face incident light rays. The incident light rays can comprise laser light having data modulated thereon. An emulsion material is disposed over the second surface of the first element and has a recorded interference pattern that diffracts the incident light rays that pass through the first element. A second element overlies the emulsion material and is structured to pass resulting light rays derived from the incident light rays and diffracted from the recorded interference pattern. A plurality of reflective elements are positioned adjacent to the first and second elements. The reflective elements fold the resulting light rays within the second element, thereby allowing a reduction in separation length between the emulsion material and receiver electronics.

Abstract: An apparatus which couples light to a fiber from a light source at an input plane while reducing back reflections includes returning light reflected back through such that the returning light does not substantially overlap with an output of the light source in the input plane. This apparatus may include a mode matching element and/or an angular distribution altering element. The apparatus may be reciprocal. The reciprocal apparatus may prevent light traversing the apparatus again having a change in phase of light from substantially overlapping an original object in an input plane.

Abstract: An optical isolator includes a first optical collimator, an isolated core, a second optical collimator and an outer tube. The first and second collimators and the isolated core are accommodated in the outer tube. The second collimator has a long sleeve which entirely accommodates the isolated core. The isolated core includes a first polarizer, a Faraday rotator crystal, and a second polarizer positioned in sequence within a toroidal magnetic core. An axial length of the toroidal magnetic core is equal to or slightly less than an overall length of the two polarizers and the rotator crystal. The two polarizers and the rotator crystal are sized such that an overall diameter of the isolated core is less than an inner diameter of the long sleeve. The magnetic core is glued within the long sleeve.

Abstract: The invention is a device for measuring angle of slant surface of an optical component and a method used therein. The slant surface of the optical component faces exactly toward the slant surface of a standard GRIN Lens and the optical component is spaced from the standard GRIN Lens by a fixed distance. Laser beams are irradiated into the vertical surface of the standard GRIN Lens and then generate two oval projections on a screen by reflection off the slant surface of the standard GRIN Lens and the slant surface of the optical component, respectively. Therefore, the angle of the slant surface of the optical component can be obtained according to the specification of the standard GRIN Lens and the dimensions of the two oval projections.

Abstract: This invention discloses an optical device including at least one first substrate defining a multiplicity of optical fiber positioning grooves, a multiplicity of optical fibers fixed in each of said multiplicity of optical fiber positioning grooves on the at least one first substrate, whereby the multiplicity of optical fibers lie in an optical fiber plane and the ends of each of the multiplicity of optical fibers lie substantially in a first predetermined arrangement in the optical fiber plane,a second substrate fixed onto the at least one first substrate such that an edge of the second substrate extends beyond the ends of each of the multiplicity of optical fibers, a lens assembly including a third substrate, and a lens fixed onto the third substrate, the lens assembly being mounted onto the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers, whereby the separation between the lens and the ends of each of the

Abstract: An automatic device for assembling a fiber collimator. The fiber collimator includes a transparent tubular holder, an optical fiber having a first end surface disposed at an end of the tubular holder, and a GRIN lens having a second end surface disposed at the other end of the tubular holder. The automatic device includes an image pick-up device, a processor, a first driving table for rotating and moving the optical fiber, and a second driving table for rotating and moving the GRIN lens. The image pick-up device films the first and second end surfaces, and outputs image data corresponding to the first and second end surfaces. The processor receives and processes the image data to control the first and second driving table to rotate so that the first and second end surfaces are parallel to each other, and control the first and second driving table to move so that a distance between the first and second end surfaces is equal to a predetermined value.

Abstract: The invention includes a multi-material structure comprising at least two components through which light is propagated. At least two structure components are of different materials and are joined to one another at an end surface of each either directly or indirectly. The end surfaces are at angles other than normal to the direction of light propagation. The multi-material structure has a polarization dependent loss less than if the components had end surfaces normal to the direction of light propagation. Embodiments of the invention are particularly applicable to a waveguide substrate/fiber capillary interface. Also included is a method of reducing polarization dependent loss between joined components through which light is propagated.

Abstract: A reflecting-mirror-type variable optical attenuator based on a new principle is provided. A reflecting-mirror-type variable optical attenuator according to the present invention is formed of a collimator lens with optical fibers in which two optical fibers are attached to a rod lens in respective positions off-centered from the optical axis of the rod lens and a linearly movable reflecting mirror. A phenomenon that the optical axis of a light beam emitted from one optical fiber deviates from the optical axis of the collimator lens by the angle according to the off-centered distance on the surface of the rod lens is utilized. That is, by changing the distance between the surface of the reflecting mirror arranged to be linearly movable in the optical axial direction back and forth and the surface of the rod lens, input light from one optical fiber is attenuated to be output to the other optical fiber.

Abstract: A collimator lens having a low reflectivity and significantly improved durability against high-power light is provided so that optical parts using the collimator lens can be reduced in size and cost lowered. A plurality of optical fibers can be connected to the collimator lens to produce a variety of fiber collimators and optical parts based on the fiber collimator. The collimator lens is made essentially of quarts glass whose refractive index is graded radially so as to increase towards the optical axis and decrease gradually towards the outer periphery. The collimator lens and optical fibers are connected directly by fusion.

Abstract: A variable attenuator employs a shutter element that is inserted into the path of a beam of radiation. The shutter element comprises a transparent substrate with an opaque layer formed on top of the substrate. The opaque layer forms a pattern in the shape of dots on one part of the substrate and in the shape of a solid layer with holes therein on another part of the substrate. The pattern of holes and dots are such that the radiation transmission function of the element varies as a smooth linear function with the length of the shutter element. Therefore, by inserting the shutter element in a direction along its length into the path of the radiation beam, the amount of attenuation of the beam can be accurately controlled.

Abstract: It is known to couple a collimated beam of light into the end of an optical fibre with a graded index lens having an angled facet at the lens/fibre interface to reduce the amplitude of Fresnel retroreflected power. The expense incurred in providing angled facets is avoided by using a two-part compound lens. One part is a graded index lens part having an axial length shorter than a quarter period. To this is bonded a cylindrical uniform refractive index lens part whose index is matched with the effective refractive index of the fibre. This reduces the amplitude of the retroreflection power by causing the displacement of the Fresnel reflection from the lens focus.

Abstract: A variety of polarization independent optical isolators, including a single stage polarization independent optical isolator, a single stage broadband polarization independent optical isolator, a double stage polarization independent optical isolator, a double stage broadband independent optical isolator, and an optical isolator/monitor/amplifier, provide improved isolation characteristics and functionality. Optical systems are based upon input light traveling twice through the optical isolator/monitor/amplifier, and upon input light traveling twice through the optical isolator/monitor/amplifier connected in cascade with a double stage broadband polarization independent optical isolator.

Abstract: A light source-optical fiber coupler constituted by: a light source (such as a semiconductor laser chip 10); and a gradient index rod lens 14 for coupling diffuse luminous flux emitted from the light source to an end surface of an optical fiber (such as a single mode optical fiber 16). The gradient index rod lens has a light source side end surface shaped like a convex spherical surface, and an optical fiber side end surface shaped like a flat surface. The gradient index rod lens is retained by the housing in the condition that the light source (laser chip) and the gradient index rod lens are disposed close to each other. The distance between a surface of the laser chip and an end surface of the gradient index rod lens is preferably selected to be not larger than 0.3 mm and more preferably in a range of from about 0.2 mm to about 0.25 mm.

Abstract: This invention discloses an optical collimator lens for collimating an incident light. The collimator lens includes an optical transmission rod substantially formed as an elongated cylinder. The optical transmission rod further includes a first end surface formed as a spherical or aspherical end surface and a second end surface opposite the first end-surface. The second end surface formed as an inclined planar surface having an incline angle &thgr; relative to the optical axis of the optical transmission rod for increasing a return loss from the inclined planar surface. In a preferred embodiment, the inclined planar surface has an incline angle of substantially eight degrees or less or more.

Abstract: An imaging optical apparatus comprising a gradient-index rod lens array and two transparent or light transmitting optical elements that are substantially identical in shape and imaging characteristics and which are provided in the object space and the image space in the optical path of said gradient-index rod lens array in such a way that they are symmetrical with respect to said gradient-index rod lens array.

Abstract: A mode converter includes first and second optical waveguides and a GRIN fiber lens. The GRIN fiber lens is attached to both the first and the second waveguides.

Abstract: An optical filter arrangement that is especially useful for optical signal transmission, multiplexing and demultiplexing purposes has an optical filter, a reflecting arrangement, and a holder for holding the optical filter and the reflecting arrangement.

Abstract: A GRIN fiber lens has a silica-glass core whose refractive index has a radial profile. The profile has a radial second derivative whose average magnitude in the core is less than about 1.7×10−6 microns−2 times the value of the refractive index on the axis of the GRIN fiber lens.

Abstract: A structure and method for adjusting waveforms of optical filters used in a DWDM system comprises a filter, a GRIN lens and a biporose pigtail with two holes therein. The holes are parallel to a center-axis of the pigtail but at different distance from the center-axis thereof, an input and return optical fiber are secured within the two holes. The GRIN lens is provided with a first end coupled with the biporose pigtail, thus signals from the input fiber can input the lens and the reflected signals from the lens can enter into the return fiber. The GRIN lens further defines a second end angularly to the axis thereof. The filter transmits determining wavelength and is joined with the second end of the GRIN lens.

Abstract: A method for making an optical collimating device having three or more ports. A test light having the same wavelength as that at which the filter is designed to operate is transmitted through the input collimator. The angle of incidence is measured, and the location where the reflected beam reaches the ferrule is determined. The data dictates where the output fiber pigtail should be positioned within the ferrule to achieve the measured angle of incidence for that transmitted wavelength and the spacing between input and output pigtails based on the angle of reflection. Multiple ferrules containing two or more pigtails corresponding to a particular filter operating at a particular wavelength are segregated into separate collimator bins that are marked accordingly.

Abstract: A method and apparatus for achieving broad gain bandwidth in a Raman amplifier using a wavelength multiplexed pump source is provided. The pump source offers high power, broad bandwidth, and the ability to tailor the pump spectrum, thus providing a means to achieve gain flattening within a specific band of the Raman amplifier. The pump source is preferably comprised of one or more multi-gain element arrays multiplexed together within a single external resonator cavity. Interposed between the array and the resonator cavity output coupler are a collimating element and a diffraction grating. The collimating element can be a refractive optic, a ¼ pitch GRIN lens, or a reflective optic. The diffraction grating can either be transmissive or reflective. The combination of the diffraction grating and the collimating element forces each emitter within the array to lase at a distinct wavelength.

Abstract: A method and apparatus for assembling optical components and a substrate. A glass coating is located at the inner base between the optical component and the substrate. The assembly of the component, substrate and glass coating can be used in the field of imaging and in particular for endoscopy.

Abstract: There are disclosed an optical filtering module and various optical devices using the filtering module. The optical filtering module has an optical filter for transmitting, attenuating or reflecting light having a certain wavelength range, a first optical system having an optical fiber for guiding light to be transferred to the optical filter, a second optical system having an optical fiber for guiding light transferred from the optical filter, the second optical system being opposingly arranged to the first optical system while interposing the optical filter therebetween and an outer cylindrically shaped glass holder for holding therein the optical filter, the first optical system and the second optical system secured thereto.

Abstract: An optical integrator for an illumination device of a microlithographic projection exposure system has a rod made of a material transparent for ultraviolet light and with a rectangular cross-section. A rod arrangement with, for example, seven small rods made of the same material is arranged before the entrance surface of the rod. The aspect ratio between width and height of the small rods is the inverse of the aspect ratio between width and height of the rod. The rod arrangement, or some analogous structure, surface or treatment substituted therefor, serves to compensate the direction-dependent total reflection losses of the rod.

Abstract: Ultra-small optical probes comprising a single-mode optical fiber and a lens which has substantially the same diameter as the optical fiber. The optical fiber and lens are positioned in a probe housing which is in the form of an insertional medical device such as a guidewire. Connector elements are provided to facilitate the attachment of the probe to an optical system and the quick disconnection of the probe from the optical system. The probe is used to obtain optical measurements in situ in the body of an organism and can be used to guide interventional procedures by a surgeon.

Abstract: Optical fiber terminations requiring collimated output from single-mode fibers (SMF) have been accomplished in the past through use of graded index lens (GRIN) technology. GRIN lenses are expensive, difficult to mount and align, require adhesive bonds, and are relatively large compared to the optical fiber diameter. The use of a UV laser refractive index tunable fused multi-mode fiber as a termination collimator provides a more compact, durable, inexpensive means of coupling single-mode optical fibers to other components, even those of uneven numerical aperture. Determining the exact length required for proper collimation is avoided by utilizing a laser tuning process to adjust the refractive index of the fiber to produce required collimation.

Abstract: A system of assembling a WDM filter assembly including a filter assembly and a collimator includes a holding means for accepting and holding one of the filter assembly and the collimator, a pivotal means for pivotally moving one which of the filter assembly and the collimator is not held, a detecting means for detecting a signal going through the WDM filter assembly, and a control means for applying a driving signal to drive the pivotal apparatus by using a pin to offset the interfence between materials until the detected siganl is within a predetermined process tollerance, whereby the filter assembly is aligned with the collimator.

Abstract: An optical filtering assembly used in temperature compensated 3-port filtering or isolating packages is described. The optical path is comprised of two (input and reflective) optical glass fibers inserted into dual-capillary glass ferrule to produce a fiber-ferrule sub-assembly, a collimating (GRIN or aspheric) lens, a spectral shaping glass filter and an output collimating assembly. The lens collimates the light emitted from the input optical fiber into parallel rays, which hit the filter. The filter splits the collimated light into two beams. The transmitted beam is spectrally modified by the filter, and couples into the output collimating assembly. The second beam is reflected from the filter through the lens into the adjacent (reflective) optical fiber. The optical components are assembled and aligned so that the transmitted and reflected light beams are collimated and their insertion losses (IL) are minimized.

Abstract: An optical switch for processing an optical signal includes a refractive material having a first surface, a second surface, and a third surface. A first embodiment of the optical switch includes a lens having a planar surface that is coupled to the third surface of the refractive material, and a convex surface. A second embodiment of the optical switch includes a collimating lens, a first decollimating lens, and a second decollimating lens. The optical switch further includes a switchplate coupled to the second surface of the refractive material. The switchplate has a first position spaced apart from the second surface and a second position in proximal contact with the second surface.

Abstract: An optical system for coupling light from a monolithic waveguide chip from one optical path to another on different layers of the chip or into or out of the chip along an edge thereof by coupling a GRIN lens to the edge. Coupling a GRIN lens having a reflective end allows light to be launched out of and back into the waveguide chip. Alternatively a GRIN lens having a plurality of fibers coupled thereto can be used to couple signals carried by the fibers into the waveguide chip.

Abstract: A light emitting and receiving device consists of a light propagating member provided with a light emitting means for converting first electrical signals into first optical signals, and a light receiving means for receiving and converting second optical signals into second electrical signals. The light receiving means is disposed coaxially with an optical fiber. The light propagating member is situated between the optical fiber and the light receiving means. The light emitting means emits the first optical signals into the optical fiber, and the light propagating member receives from the optical fiber and propagates therethrough the second optical signals to the light receiving means. Loss of optical power is suppressed, and a downsized light emitting and receiving device is attained.

Abstract: A rod lens for an optical communication module is not easily damaged An input side end surface of the rod lens has an inclined surface The inclined surface is inclined by a predetermined angle with respect to a central axis of the rod lens to reduce the reflection loss. A flat contact surface, which is perpendicular to the central axis, is formed on the distal end of the rod lens. By simply arranging two of the rod lenses to contact each other, the rod lenses are optically coupled in the optimum manner without being damaged.

Abstract: An apparatus and method of manufacturing multiple-port optical devices and packages includes the steps of positioning pairs of screened optical fibers in a precision ferrule of a collimating assembly; determining a desired angle of incidence (AOI) for an optical element; positioning the assembly in a moveable fixture; moving the assembly into engagement with an optical element holder unit having an optical element mounted thereto; micro-tilting the element holder to actively align the optical element and fibers to preferably achieve an insertion loss (IL) less than about 0.2 dB; and curing adhesive to initially secure the aligned optical element assembly.

Abstract: Methods of making a multiple-port optical device include precisely positioning pairs of optical fibers inside of a fiber ferrule using a positioning means, such as shaped capillaries or an external clamp, to hold the position of the fibers while adhesive is applied to the fibers and cured. The external precision positioning means comprise silicon wafers which are etched to form capillaries or guides for the fibers. Adhesive is applied to the fibers and wicked into the fiber ferrule capillary to completely fill the capillary. The external positioning means is removed after curing and the fiber ferrule is polished for use in optical devices such as multiple-port DWDM filter packages.

Abstract: An optical fiber collimator array includes an optical fiber array block and a microlens array substrate. The optical fiber array block includes an angled surface and is configured to receive and retain a plurality of individual optical fibers, which carry optical signals. The microlens array substrate includes a plurality of microlenses integrated along a microlens surface and a sloped surface opposite the microlens surface. The microlens surface is coupled to the angled surface such that the optical signals from the individual optical fibers are each collimated by a different one of the integrated microlenses.

Abstract: An optical device includes an optical waveguide with a block that is fusion spliced to one end. The block has a refractive index approximately equal to the effective refractive index of the waveguide and is of such a length that substantially all the light exiting the waveguide propagates directly to the end of the block remote from the waveguide.

Abstract: An optical fiber collimator having a lens (10), and an optical fiber chip (14) disposed at a distance from the lens, the optical fiber chip holding an end portion of an optical fiber (12) and having an end surface treated to be inclined. The optical axis of the optical fiber is made eccentric with respect to the center of the lens to set the eccentric quantity of the optical fiber so that the center of the lens substantially coincides with the center of a light beam incident on the lens. The kind of the lens is optional. The lens may be an inexpensive spherical lens or may be a gradient index rod lens. When a gradient index rod lens is used, a lens in which a surface facing to the optical fiber chip is treated to be inclined is used as the gradient index rod lens.

Abstract: A method of manufacturing a collimating assembly includes the following steps: preparing a GRIN lens subassembly; preparing a dual-fiber (DF) pigtail subassembly; fitting the GRIN lens subassembly and the DF pigtail subassembly together; applying epoxy onto a junction zone between the GRIN lens subassembly and the DF pigtail subassembly; and baking the junction zone for curing the epoxy thereof until the epoxy spreading uniformly over the junction zone due to the so-called capillarity phenomenon.

Abstract: A multiple-port optical device uses improved fiber ferrules comprising various capillary designs and shapes to precisely position optical fibers and, in particular, the optical fiber cores. The fibers are screened for geometric characteristics which further aide in precisely positioning the fiber cores. The ferrules, capillaries, fibers, and adhesives are combined to reduce adverse thermal effects and maintain the position of the fibers over a broad range of environmental conditions in which DWDM packages and modules are required to operate.

Abstract: A lens function-including optical lens according to the present invention is constituted by: at least one step-index optical fiber; and at least one gradient index optical fiber having an outer diameter equal to that of the step-index optical fiber and having a periodic length exhibiting a lens function, the gradient index optical fiber being joined or attached to an end surface of the step-index optical fiber. The present invention is especially effective in a single mode optical fiber which is typical of the step-index optical fiber. The gradient index optical fiber can be produced by an ion exchange method.

Abstract: A blockless optical multiplexing device and a method of making a blockless optical multiplexing device. The blockless optical multiplexing device comprises at least one unit, where that at least one unit is hermetically sealed in a housing. The unit further comprises a substrate that is placed into a base portion of the housing, a plurality of optical filters that are precisely secured onto the substrate, with one half of the optical filters being separated by an air gap from a second half of the optical filters, an input collimator that is mounted onto the substrate, and a plurality of output collimators that are mounted onto the substrate, with a respective one of the output collimators being aligned and associated with a respective one of the optical filters. In a preferred embodiment, the number of optical channels in the optical multiplexing device is equal to the number of the plurality of optical filters secured onto the substrate.

Abstract: An apparatus and method of building multiple-port optical devices characterizes optical filters according to a desired angle of incidence. Fiber ferrules are manufactured to precisely position at least two pairs of optical fibers inside the ferrules. The fiber ferrules are then characterized according to the distance between the fiber cores of the fiber pairs (i.e. the separation distance). The filters and the fiber ferrules are matched according to predetermined tolerances. The filter, or other optical element, is optically aligned with each pair of optical fibers and bonded into place. Light signals, such as DWDM signals, are then transmitted through the devices and the single filter or optical device operates on the multiple signals.

Abstract: Optical package and module designs use multiple-port (e.g. six-port) optical packages to create compact DWDM modules, add/drop packages, heat dissipation packages, optical amplifier filters, and the like.

Abstract: The invention relates to an optical fiber and a fiber termination which provide an output of laser light propagating through the fiber in a required direction while focusing it into a small spot. In one embodiment of the invention the termination includes a tapered fiber rod with an angled ball formed at the end of the rod. A corresponding method of manufacturing of the termination is provided. In another embodiment the termination includes a fiber rod having an angled end and a GRIN lens disposed so as to receive light reflected from the angled end, the lens being an integral part of the termination. In other embodiments the lens is replaced with a cylindrical or tapered multimode stub which provide similar function.

Abstract: A light source-optical fiber coupler using a gradient index rod lens 12 by which a diffused luminous flux emitted from a light source (for example, a semiconductor laser 10) is coupled onto an end surface of an optical fiber (for example, a single-mode optical fiber 14) . The gradient index rod lens has a planar end surface facing the light source, and a convex spherical end surface facing the optical fiber. The gradient index rod lens has a light source side numerical aperture NA2 in a range of from 0.40 to 0.75, an effective lens radius r0 in a range of from 0.3 to 1.0 mm, and a spherical curvature radius P1 in a range of from 1.2 to 2.0 mm.

Abstract: In order to correct optical couplers, which couple light among optical fibers arranged at an input (light source) port and output ports which are spaced off the optical axis of the coupler for optical aberration, including astigmatic aberration, anamorphic lenses are used in the coupler instead of lenses with rotationally symmetric surfaces. The anamorphic lenses may be collimating and decollimating lenses arranged along an optical axis on opposite sides of a wave length beam splitting filter which reflects and transmits different portions of the source spectrum. These lenses are anamorphic lenses with toroidal surfaces instead of rotationally symmetric surfaces, as in such couplers of conventional design. The wave front error and the insertion loss of the coupler is substantially reduced providing a substantial improvement in coupling efficiency and in coupling system performance.

Abstract: This invention provides a novel class of fiber-optic couplers that enable fiber-optic elements in an angled-axis alignment to be coupled in a secure and reliable manner. The fiber-optic couplers of the present invention further permit a variable gap between two successive optical elements that are coupled. This has an important practical application, for it allows GRIN lenses with a pitch less than a quarter-pitch to be employed. By cascading and/or telescoping a plurality of these fiber-optic couplers, the present invention further provides an assembly of fiber-optic systems that can be utilized as wavelength division multiplexers and de-multiplexers. An important advantage of the fiber-optic couplers of the present invention is that they allow fiber-optic elements to be arranged in various ways, yet still attaining secure and reliable coupling.