Abstract: A rotating periodic color-regulating module of the image display device is disclosed to improve the usage of light. The rotating periodic color-regulating module comprises a color separating light guide and a color-regulating processor. By using a grating element installed in front of the color separating light guide, the incident light is interleaved into three parts of different wavelengths, red (R), green (G) and blue (B), propagating toward the corresponding color filters. Part of the light is reflected by the color filters, then reflected by the mirror around the grating element, and goes back to the color filters. The incident light is divided into three uniform beams of light, R, G and B, to the color-regulating processor. The color-regulating processor changes the outgoing position and order of the light beams periodically and rapidly for displaying image.

Abstract: There is provided a projection display apparatus using a polarization beam splitter having two splitting surfaces, which can simplify its structure and reduce its cost. The projection display apparatus includes the polarization beam splitter that has a first splitting surface for transmitting or reflecting a red light and a second splitting surface for transmitting or reflecting a green light and a blue light. A polarization state converter that is provided in the polarization beam splitter converts the polarization states of the green and blue lights and applies the converted green and blue lights to the polarization beam splitter.

Abstract: The invention provides an optical device, including a light-transmitting substrate, optical means for coupling light into the substrate by total internal reflection, and a plurality of partially reflecting surfaces carried by the substrate, characterized in that the partially reflecting surfaces are parallel to each other and are not parallel to any of the edges of the substrate.

Abstract: An apparatus includes a mixer, a combiner and first and second reflectors. The mixer has first and second inputs and has first and second outputs. The combiner includes first and second parts where the first output provides a mixed signal to the first part and the second part provides a combined signal to the second input. The first reflector receives a remaining signal from the first part and provides a reflected composite signal to the second part. The second reflector receives a split off pump signal from the first part and provides a reflected pump signal to the second part.

Abstract: An auxiliary optical unit attachable to an optical device for optional use therewith, includes: (a) an afocal teleconverter lens system having a predetermined magnification; (b) a laser range finder system for measuring and displaying the range to viewed object; and (c) a beam splitter located within the auxiliary optical unit such that when the auxiliary optical unit is attached to the optical device, both the displayed range and the object are concurrently viewable by the optical device. In the described preferred embodiment, the optical device is a telescopic gun sight to which the auxiliary optical unit is quickly attachable, to provide range display and increased magnification whenever desired.

Abstract: The present invention relates to a method and system for expanding a laser beam. An illumination system includes a horizontal reflective multiplexer and a vertical reflective multiplexer. The horizontal reflective multiplexer replicates the input beam along a first dimension to form a first multiplexed beam. The vertical reflective multiplexer replicates the first multiplexed beam along a second dimension to form a second multiplexed beam. In one example, the horizontal reflective multiplexer includes a first beam splitter, second beam splitter, and mirror. The vertical reflective multiplexer includes a beam splitter and mirror.

Abstract: Disclosed is a color separation and color synthesis optical system provided between a light source portion and a projection optical system in a reflection type projection display apparatus, which color-separates a white color beam emitted from the light source portion into three primary color light beams of R (red), G (green) and B (blue), guides the three primary color light beams to a plurality of spatial light modulators corresponding to R, G and B, and color-synthesizes color light beams optically modulated by the respective spatial light modulators for the colors depending on video signals to emit a color-synthesized light beam, wherein at least one or more wavelength-selective polarization converting plates which rotate a plane of polarization of a specific color light beam by 90 degrees are located, and the wavelength-selective polarization converting plate is adhered to an incidence plane and/or an emission plane of a polarization beam splitter by adhesive with a slight gap.

Abstract: A polarizing illumination optical system includes a light source with a parabolic reflector with a light emitter at its focal point so that the light source emits substantially collimated light toward a polarization conversion optical system that separates the light into two polarizations, converts the light to a single polarization, and projects the light through an optical integrator that includes two integrating plates so as to provide a more uniform intensity light beam. The polarization conversion optical system satisfies the following condition: 4 f<D<7 f, where f is the focal length of the parabolic reflector, and D is the minimum width of the optical incidence aperture of the polarization conversion optical system. A projection display device uses the polarizing illumination optical system to illuminate modulators, such as LCDs, that provide different color image components that a projection lens projects on a screen to provide a full color image.

Abstract: A parallel glass plate mounted on a rotating fixture is used to precisely control the optical path length of a light beam. The glass plate refracts the incident optical signal to increase the length of its optical path as a function of the angle of incidence. The device can easily achieve a precision in the order of nanometers and is particularly suitable to fine tune the cavity length of a resonator and the optical path difference of an interferometer. Accordingly, the preferred application of the invention is in an interferometric interleaver. The glass plate can also be coated with a partially reflective coating to attenuate the optical signal passing therethrough. By judiciously selecting the refractive index, the thermal coefficient of refraction, and the coefficient of thermal expansion of the glass, thermal effects may be virtually eliminated.

Abstract: An optical element such as a beam splitter for interferometer separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers can conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.

Abstract: A photonic switch for an optical communication network includes a matrix of actuator-mirror assemblies and a corresponding matrix of optical ports. A first one of the actuator-mirror assemblies directs a beam of light received from an input optical port to a reference mirror, where it is reflected to a second actuator-mirror assembly that redirects the beam to an output optical port. Each of the actuator-mirror assemblies includes a mirror-coil assembly mounted to a gimbal, with stationary magnets being positioned adjacent a corresponding one of the coils such that when current flows through the coils a force is generated that causes the mirror-coil assembly to tilt. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: A digital projection apparatus (10) for projection of a multicolor image uniformizes polychromatic light from a light source (12) and provides magnification to the uniformized illumination beam using a base condenser relay (80), providing a reduced numerical aperture for conditioning at a dichroic separator (27). For each monochromatic component color provided from the dichroic separator (27), a reducing relay (82) then demagnifies the illumination beam to provide source illumination to a spatial light modulator (30) at an increased numerical aperture. As a result, color shading across the field is minimized and brightness is optimized.

Abstract: A method for fabricating a geometric beamsplitter involves applying a reflective coating having at least one metallic layer to a transparent substrate. A pattern of holes containing numerous holes that are preferably randomly distributed over its reflective surface is created in the reflective coating using laser processing. The method allows inexpensively fabricating beamsplitters that have accurately defined transmittances. Beamsplitters in accordance with the invention are suitable for use as dosimetry mirrors on, for example, the illumination systems of microlithographic projection exposure systems.

Abstract: Pathlength matched optical devices (such as beam splitters) are produced by viewing optical paths through the optical devices and adjusting relative positions of optical components of the optical devices until the viewed optical paths are equivalent. The optical paths begin at markings at different locations on the optical device. The optical pathlengths are equivalent when both markings are in focus in a limited field of view camera or lens. In a beam splitting cube constructed of two prisms, markings located at precisely similar locations on different prisms are pathlength matched when coincident as viewed at a reference face of the cube. The prisms are abutted at their diagonals and are adjusted by sliding the prisms along the diagonals to the pathlength matched position. Optical adhesive between the prisms is cured after fixing the prisms at the pathlength matched position.

Abstract: The invention relates generally to optical interference filters and interferometers. Methods, devices and device components are presented for separating closely spaced optical channels with minimized cross talk. The invention provides optical interference filters having parallel phase control elements which efficiently transmit light of a selected optical channel or a plurality of selected channels with decreased light loss, particularly decreased insertion loss. An exemplary interference filter of the present invention provides minimized vertical and horizontal recombination error and improved optical path length matching. The invention further provides methods of fabricating optical interference filters with improved piece-to-piece reproducibility.

Abstract: The invention concerns an optical instrument having at least one binocular viewing port, in which in the two channels of at least one binocular beam path there are provided beam splitters that make it possible to reflect a portion of the beam path out onto an imaging device or the like, and to reflect into the respective channel, toward the viewing port, data or images that have been made available.

Abstract: A method and system for performing swept-wavelength measurements within an optical system incorporating a reference resonator provides improved operation in resonator-enhanced optical measurement and data storage and retrieval systems. The system includes an illumination subsystem, an illumination coupler for producing a measurement beam and a reference beam from an output of the optical illumination source, a reference resonator for receiving the reference beam, a measurement resonator for receiving the measurement beam, at least two detectors, one optically coupled to the reference resonator and one optically coupled to the measurement resonator, and a time-domain measurement system coupled to the detectors for comparing detected optical signals received from the resonators. The detected signal from the reference resonator is used to compensate or detect variations in the wavelength of the illumination system, improving the resolution and accuracy of the measurement provided by the measurement resonator.

Abstract: An image projection system utilizing a convergent light source and an optical polarizing module. The optical polarizing module includes a wire grid polarizing beam splitter (WG-PBS), reflecting S-polarized light, forming a first beam, and transmitting P-polarized light. A mirror is disposed near the WG-PBS at a predetermined acute angle to reflect light with S-polarization, passing through the WG-PBS again and forming a second beam. A first lens array couples the first and second beams and individually directs the first and second beams to different portions on a second lens array. The second beam with P-polarization is directed to a plurality of half-wave plates and converted into S-polarized light, which can be modulated by a liquid crystal display panel to project an image.

Abstract: A polarization splitting grating coupler (PSGC) connects an optical signal from an optical element, such as a fiber, to an optoelectronic integrated circuit. The PSGC separates a received optical signal into two orthogonal polarizations and directs the two polarizations to separate waveguides on an integrated circuit. Each of the two separated polarizations can then be processed, as needed for a particular application, by the integrated circuit. A PSGC can also operate in the reverse direction, and couple two optical signals from an integrated circuit to two respective orthogonal polarizations of one optical output signal sent off chip to an optical fiber.

Abstract: A beam splitter (24) for splitting light in a wavelength range of about 500 nm to about 600 nm is arranged in a relay optical system of a taking lens (12). A green light beam reflected from the beam splitter (24) is directed through a relay lens (R3) to a focusing state determination imaging unit (26). The imaging unit (26) comprises three imaging elements (A, B, C) for capturing the directed green light beam to determine the focusing state. Thus, a device for determining the focusing state of the taking lens is provided, in which the green light beam is separated as an object light for determining the focusing state from the object light entering the taking lens (12), so that the focusing state can be determined with high accuracy on the basis of the high-frequency components of the image signal generated by capturing the green light beam by means of the imaging elements (A, B, C) having different optical path lengths.

Abstract: An apparatus that efficiently and accurately directs or splits a non-polarized light beam input from a fiber optic into one, two, four or eight output beams wherein the light beam input is passed through a collimator, the apparatus uses non-polarizing beam splitters and the output beams are coupled to fiber optics using a lens matched to divergence of the beam to direct the beam into the fiber optic and uses an iris diaphragm attenuator to adjust the energy of the output beam prior to its entry into the fiber optic.

Abstract: An optical system of an optical pick-up includes a light source portion that selectively emits a first laser beam (shorter wavelength) and a second laser beam (longer wavelength), and an objective lens for converging the first laser beam onto a first optical disc and for converging the second laser beam onto a second optical disc. The second optical disc has lower recording density and a thicker cover layer than the first optical disc. The divergence of the second laser beam incident on the objective lens is larger than that of the first laser beam, correcting one part of spherical aberration caused by a difference in thickness of the cover layer. A diffractive lens structure is formed on a surface of the refractive lens so that the residual part of the spherical aberration is corrected by switching the wavelength of the laser beam.

Abstract: A projector arrangement has a light-splitting and recombining device that divides white light into red, green and blue light output at respective surfaces, and recombines red, green and blue light input to these respective. A transparent base body of the arrangement contains a layer of a material with lower refractive index and at least one layer of a material with higher refractive index. The lower refractive index is selected so that 1.7≦NLS≦2.1 and the refractive index of the transparent base body is selected so that 1.52≧NK≧1.

Abstract: A substantially passive optical image processor providing image dissection into orthogonally polarized components each modulated on a pixel-by-pixel basis in one or more encounters with an included polarization-altering modulator element of electrical or optical nature. The modulation-processed images are recombined into an output image of the processor. Alternate arrangements of the invention are also described, arrangements including multiple modulation event processing in a plurality of forms and the accommodation of multiple input and multiple output processor images. Mathematical description of the processor's function is included along with identification of real world uses of the invention. Holographic uses of the invention are also disclosed. The underlying concepts of the invention are viewed as applicable to both present day slower and faster future optical materials.

Abstract: An interleaver is provided with an optical system configured to split light having traveled from a first port to a half mirror, into two beams and direct the beams toward first and second reflectors, respectively. Light reflected by the first reflector and arrived at the half mirror is split into two beams and directed toward second and third ports, respectively. Light reflected by the second reflector and arrived at the half mirror is split into two beams directed toward the second and third ports, respectively. An etalon filter configured to cause a loss on either one of light incident thereto from the first port and the beams directed toward the second port and toward the third port.

Abstract: Accurate simulation of sport to quantify and train performance constructs by employing sensing electronics for determining, in essentially real time, the player's three dimensional positional changes in three or more degrees of freedom (three dimensions); and computer controlled sport specific cuing that evokes or prompts sport specific responses from the player that are measured to provide meaningful indicia of performance. The sport specific cuing is characterized as a virtual opponent that is responsive to, and interactive with, the player in real time. The virtual opponent continually delivers and/or responds to stimuli to create realistic movement challenges for the player.

Abstract: A light engine for more efficiently transmitting light reflected or refracted from a light source to the face of an optical transmission element such as an optical fiber or optical fiber bundle. The light engine includes a light source disposed at a focus of four ellipsoidal reflectors, where the reflectors are arranged at 90 degrees relative to one another. A condensing lens is used with each reflector to focus forwardly directed, low angle light rays onto a target plane. Each reflector serves to reflect only the accurate, high angle light rays towards the target plane. Each reflector and its associated condenser produce a light beam having a reduced diameter (i.e., spot size) while also increasing the amount of optical energy directed at its respective target plane. Collectively, the spot sizes of the four beams are significantly smaller in area than the collective size of beams produced by a conventional single or dual ellipsoidal light engine.

Abstract: This invention relates to an illumination system and method for imaging thermosensitive or light-sensitive media such as printing plate precursors. More particularly, this invention is directed to an illumination system in which laser light is conveyed to a modulator, and the modulated laser light is passed through separating means to permit only the passage of zero order radiant energy which is employed to image the media.

Abstract: A system (S) for combining multi-spectral images of a scene includes a channel (18) for transmitting a scene image (10) in a first spectral band. A separate, second detector (22) senses the scene in a second spectral band. The second detector (22) has an image output that is representative of the scene. A display (28) displays an image (12) in the second spectral band. A beam mixer (30) combines the image output (10) in the first spectral band with the displayed image (12), and conveys the combined multi-spectral images to an output (32) for a user (U).

Abstract: A method and system for providing different magnified images of an electronic device. The vision system has a first beamsplitter for receiving an image of the device illuminated by a light source, the beamsplitter providing multiple of images of the device; optical elements for receiving the plural images of the device, each of the optical elements magnifying the image by a predetermined magnification factor to produce more than one magnified images; and a second beamsplitter for receiving the magnified images and filtering out all but one of the magnified images based on a wavelength of the light source.

Abstract: A fiber optic isolator device is used by fiber optic systems operating at more than one wavelength. The device may be inserted anywhere within the fiber network. The fiber optic device permits the separation of the wavelengths so that an optical isolator module can isolate a first wavelength without significantly affecting the second wavelength. This device is useful isolating a communications signal at 1.55 &mgr;m while avoiding significant losses for an optical time domain reflectometry signal, for example at 1.3 &mgr;m.

Abstract: According to the present invention, a laser annealing apparatus (10) includes a beam splitter (14) composed of first and second beam splitters (21, 22) disposed in parallel to each other to split one laser beam into four laser beams not interfering with each other, and a reflecting mirror (23). Upon the second beam splitter (22), there are incident a transmitted beam from the first beam splitter (21) and a laser beam outgoing from the first beam splitter (21) and then reflected by the reflecting mirror (23). The second beam splitter (22) provides two transmitted beams to outside, and the reflecting mirror (23) reflects the reflected beam from the second beam splitter (22) for traveling to outside. The distance between the two beam splitters (21 and 22), and the distance between the first beam splitter (21) and reflecting mirror (23), is larger than L/(2 cos &thgr;) (where &thgr; is an incident angle and L is a coherence length).

Abstract: A single polarizer projector with a color switch and a projection method thereof, wherein the mean luminance of the inputted video signal is calculated so that the transmittance of the color switch can be controlled by the mean luminance in such a fashion that the transmittance is set to a maximum (100%) while setting the same to a low level (50%), thereby preventing unnatural blackening of relatively dark image for improving the contrast ratio.

Abstract: A pellicle comprising a box-shaped pellicle frame having top and bottom openings, and a pellicle sheet bonded to the pellicle frame to cover one of the openings of the pellicle frame, wherein the pellicle frame is made of quartz glass, a plurality of vent holes are formed as distributed on opposing side walls of the pellicle frame, and the size of the vent holes in the direction of the height of the pellicle frame is at most ⅗ of the height of the pellicle frame.

Abstract: An add-drop filter, utilizing chiral elements, that enables a new signal to be added at a particular vacuum wavelength &lgr;′k to a fiber optic line carrying n signal channels over a band of wavelengths encompassing &lgr;1 . . . &lgr;k−1, &lgr;k, &lgr;k+1 . . . &lgr;n, while an existing signal, &lgr;k, is simultaneously dropped from the signal group.

Abstract: White light emitting LED luminaire incorporates an array of red, green and blue emitting LEDs and a feedback arrangement to maintain a desired color balance. The feedback arrangement includes photodiodes positioned and enabled to separately measure the light output of each RGB color component. In one embodiment, a single photodiode or array of photodiodes is positioned to intercept reflected light from a partially reflecting element placed in the path of the combined output of the LED array. Individual colors are measured sequentially by pulsing the LEDs and photodiodes or by the use of color filters. In an alternate embodiment, each LED has an associated photodiode, either incorporated into the LED package or in a separate package.

Abstract: A multi-beam tool is disclosed which can perform square, plumb, and level function which may be required in a construction environment. The tool can generate in a preferred embodiment up to five orthogonal beams with two beams being plumb and three beams being leveled. Combinations of two level beams, or a level and a plumb beam in orthogonal arrangement can produce a square alignment set of beams. The tool includes in a preferred arrangement a self-leveling pendulum to which a laser and quad-mirror arrangement is secured. The self-leveling pendulum is dampened in order to allow the tool to settle down and provide alignment after the tool is positioned as desired.

Abstract: The invention relates generally to optical interference filters and interferometers. Methods, devices and device components are presented for separating closely spaced optical channels with minimized cross talk. The invention provides optical interference filters having parallel phase control elements which efficiently transmit light of a selected optical channel or a plurality of selected channels with decreased light loss, particularly decreased insertion loss. An exemplary interference filter of the present invention provides minimized vertical and horizontal recombination error and improved optical path length matching. The invention further provides methods of fabricating optical interference filters with improved piece-to-piece reproducibility.

Abstract: The light which is input from an optical fiber to a first port is output to an optical path. The light which is input from the optical path to a half mirror is branched into two, and is output to the optical paths. The light which is output to the optical path reaches to and is reflected from a first reflecting mirror, and returns to the half mirror by an optical path. The light which is input to the half mirror by the optical path is branched into two, and is output to the optical paths. The light which is output to the optical path reaches to and is reflected from a second reflecting mirror, and returns to the half mirror by an optical path. The light which is input to the half mirror by the optical path is branched into two, and is output to the optical paths. The light which is output to the optical path is output from a second port to an optical fiber, and the light which is output to the optical path is output from a third port to an optical fiber.

Abstract: The invention features an imaging system for imaging an object point to an image point. The system includes: a beam splitter positioned to receive light rays from the object point and separate each ray into a transmitted portion and a reflected portion, the transmitted portions defining a first set of rays and the reflected portions defining a second set of rays; and a reflecting surface positioned to receive one of the sets of rays from the beam splitter and focus that set of rays towards the image point via the beam splitter.

Abstract: A projector has an illuminating optical system for irradiating white light, a color switching optical system for dividing the white light irradiated by the illuminating optical system into color lights in a time-division manner, a DMD™ for modulating the respective color lights in accordance with an image signal, a projection optical system for projecting the light beam modulated by the DMD, a light-composite optical system for getting the light beam not incident on the projection optical system to be incident again on the DMD and a device controller for controlling the operation of the projector, where the light beam irradiated by the DMD and not incident on the projection optical system is irradiated as a light beam of uniform illuminance distribution by the light-composite optical system and is again introduced on an illumination optical axis to be incident on the DMD, thus enhancing peak luminance of the projected image and achieving high contrast ratio.

Abstract: The present invention relates generally to various arrangements of optical and electronic components to form a high-resolution helmet mounted display (HMD) or other compact display device. In particular, the current invention is designed in such a way as to allow it to operate utilizing several different kinds of image generation device and to incorporate many different features including the option of “eye tracking”.

Abstract: This invention discloses a color separation prism assembly. The prism assembly includes three triangular-shaped prisms having identical shape and size. Each of the three triangular-shaped prisms has two triangular surfaces as interfacing surfaces bonded to two identical triangular surfaces of two other prisms. At least two triangular surfaces of the three triangular-shaped prisms are coated with color separation filtering films for reflecting a first color light and transmitting a second color light therethrough. At least two triangular surfaces of the three triangular-shaped prisms are coated with a total reflective coating constituting at least two total internal reflective (TIR) surfaces for reflecting a light projected thereon. Each of the TIR surfaces further comprising a phase-shift compensating coating coated thereon.

Abstract: A system (S) for combining multi-spectral images of a scene includes a channel (18) for transmitting a scene image (10) in a first spectral band. A separate, second detector (22) senses the scene in a second spectral band. The second detector (22) has an image output that is representative of the scene. A display (28) displays an image (12) in the second spectral band. A beam mixer (30) combines the image output (10) in the first spectral band with the displayed image (12), and conveys the combined multi-spectral images to an output (32) for a user (U).

Abstract: The small field-of-view (FOV) limitation of current coherent beam combiner technology is overcome, enabling beam combining over significantly larger fields of view. The system includes an input to receive an input wavefront, a local oscillator to generate a reference wavefront, and an optical combiner such as a beam splitter to combine the input wavefront and the reference wavefront to produce an output wavefront which is received by a detector. According to the invention, an optical element is supported to receive the reference wavefront and generate, in effect, a plurality of local oscillator point sources which provide a set of wavefronts that cover the required wider FOV. In the preferred embodiment, the optical element is a diffuser, and may optionally include a mechanism for rotating the diffuser to reduce speckle. In an alternative embodiment the optical element is a lenslet array.

Abstract: A packaging case-encased electro-optical device includes: an electro-optical device where projection light from a light source enters an image display area, a dust-proof substrate disposed on a light incident plane or a light emitting plane thereof, a first light blocking film disposed thereon, a second light blocking film formed on an counter substrate configuring the electro-optical device, and a packaging case to house the electro-optical device and the dust-proof substrate. The second light blocking film, the first light blocking film, the dust-proof substrate and the packaging case configure a heat conducting path.

Abstract: The color display according to the invention relates to a color display device and a color display method for color display by monochromatic display of data of respective colors in synchronism with sequential ON/OFF switching of three light sources for red, green and blue, respectively. In a preferred embodiment, the red, green and blue light sources are controlled to turn on and off in the order of red, green, blue and green in each unit period and to repeat the unit period.

Abstract: An image display apparatus has a reflective display element for displaying a two-dimensional image on a display plane, a light source for emitting illuminating light for illuminating said display plane, a magnifier optical system for magnifying and projecting said two-dimensional image, and an optical member which is composed of a medium having a refractive index greater than or equal to unity and has at least three optical planes of a first plane, a second plane, and a third plane. The magnifier optical system is substantially in concentricity with said display plane; the illuminating light from said light source passes through said first plane and then through said second plane, thereby illuminating said display plane; and the reflected light from said display plane passes through said second plane and is then reflected in said first plane, thereby passing through said third plane and being incident on said magnifier optical system.

Abstract: An adjustable laser light beamsplitter and fiber optic coupler apparatus and method comprising a plurality of splitter modules placeable into an optical path, each module comprising: a splitter to split off a selectable portion of an incident polarized laser beam; a fiber coupler to capture the split-off portion into an optical fiber; and a beam transmitter element to transmit a remainder of the incident beam to serve as an incident polarized laser beam for any subsequent splitter module.

Abstract: A controllable attenuator includes a pair of collimators respectively connected to input and output fibers. A pair of reflection devices are respectively positioned behind the pair of collimators opposite to the corresponding input and output fibers. A U-like light path is defined among the pair of collimators and the pair of reflection devices. A neutral density filter is moveably positioned between the pair of reflection devices wherein a moving direction of the filter is preferably parallel to a longitudinal direction of the pair of collimators. An ND filter position indicator such as a potentiometer, is used to dynamically monitor attenuation setting.