Abstract: A lithographic apparatus arranged to transfer a pattern from a patterning device onto a substrate includes two reference gratings provided in the substrate and two measurement gratings on top of the reference gratings, the measurement gratings being similar to the reference gratings, and oppositely biased in a single direction relative to the respective reference gratings. An overlay measurement device with an image sensor is used for obtaining pixel data of a measurement spot in each of the two measurement gratings. Asymmetry for each pixel in the measurement spot is measured, and from the pixel asymmetry measurements in associated pixels of each of the two measurement gratings an overlay value and a process dependent value is determined, as well as a quality indicator for the overlay value and the process dependent value.

Abstract: A calorimeter for measuring a color of light includes a color sensing device, a suspension means and a counterweight. The suspension means suspends the color sensing device in an operative relationship relative to a color producing device, while the counterweight is secured to the suspension means and balances the color sensing device in the operative relationship relative to the color producing device.

Abstract: Essential prerequisites for any injectable product are its sterility, its freedom from pathogens and its freedom from visible particle contamination . . . . These requirements must be satisfied prior to the release of an injectable product batch for sale and use. A major difficulty in responding to these assay requirements is the need for a size sensitivity difference of 100 or greater in determining the presence of viable pathogenic organisms and of non-viable random particle contaminants. The wide dynamic testing range cannot be satisfied in current art with a single non-destructive testing station. The present invention uses a special agitation procedure to generate separate liquid volumes containing the small viable and larger non-viable particle contaminants. This separation makes possible the introduction of sensing systems that have been optimized for each size range and that can operate in parallel without interference.

Abstract: The present invention provides an optical element for measuring information of living body for noninvasively measuring a body fluid component in a test sample of living body with high accuracy, stability, and ease. The optical element includes a light incident surface, a contact surface contacting living body and having a groove to protrude living body and a light emission surface, in which a light incident from the light incident surface is applied to living body, and the light absorbed and scattered by living body is received and emitted from the light emission surface, a light transmittance controlling means is formed from the bottom part of the valley part of the groove, on at least a part of a wall surface of the light incident surface side and/or on a wall surface of the light emission surface side of the groove.

Abstract: A method and a device, using a system of plural cavity resonators, enabling to measure the light absorption or diffusion of biological samples. A measurement of low absorption or diffusion can be achieved and for example be applied for measuring the hybridization of DNA strands.

Abstract: The present invention relates to a device and method for making quantified determinations of the quality of surfaces and wherein the device comprises an optical system with a first optical means and a second optical means as well as a control and evaluation means and an output (display) means. Said first optical means comprises an illuminating means having at least one LED as its light source and serves the function of illuminating the measurement surface at a predetermined angle. Said second optical means is likewise directed at a predetermined angle to the measurement surface and receives the reflected light. A photo sensor of said second optical means emits an electrical measurement signal which is characteristic of said reflected light. The light emitted from the illuminating means is configured such that its spectral characteristic comprises blue, green and red spectral components in the visible light spectrum.

Abstract: Detecting the presence of a target material in a scene by using a multi-aperture interferometer system having a plurality of apertures at least one of which has an adjustable optical path length, by adjusting the aperture(s) to obtain a predetermined optical path length difference among the apertures, the predetermined optical path length difference being based on a source laser wavelength and a target material wavelength, illuminating the scene with the source laser, capturing a spectral data set corresponding to an interference pattern generated in the multi-aperture interferometer system for an illuminated point source in the scene, the spectral data set containing spatially distributed spectral data, and determining whether the target material is present at the illuminated point source based on a presence of spectral data in at least one side lobe of the spectral data set.

Abstract: The present invention is an alternative Fourier domain optical coherence system (FD-OCT) and its associated method. The system comprises a swept multi-wavelength laser, an optical interferometer and a multi-channel receiver. By employing a multi-wavelength laser, the sweeping range for each lasing wavelength is substantially reduced as compared to a pure swept single wavelength laser that needs to cover the same overall spectral range. The overall spectral interferogram is divided over the individual channels of the multi-channel receiver and can be re-constructed through processing of the data from each channel detector. In addition to a substantial increase in the speed of each axial scan, the cost of invented FD-OCT system can also be substantially less than that of a pure swept source OCT or a pure spectral domain OCT system.

Abstract: Position detection apparatus comprises: an incident unit that forms a parallel beam from a light beam of a light source and supplies the parallel beam to a beam splitter in a way that the separated beams, obtained from the parallel beam by the beam splitter, are respectively incident upon the reference surface and the measurement target surface at an angle; and a reflection unit that reflects the separated beams, which have been reflected by the reference surface and the measurement target surface and integrated to a light path by the beam splitter, to be supplied to the beam splitter as a parallel beam along the light path, and generates a signal corresponding to a phase difference of the separated beams by interfering a light beam that has been supplied from the reflection unit, separated by the beam splitter, reflected by the reference surface and the measurement target surface, and integrated again to a light path by the beam splitter.

Abstract: A three-dimensional shape detecting means includes a projecting device which projects pattern light; an image capturing device which captures a pattern light projection image; a pattern light position extracting device which extracts a position of the pattern light projected on the subject; a three-dimensional shape calculation device which calculates three-dimensional shape of the subject; a storage device which stores color value data of the pattern light projection image; a hue parameter calculation device which calculates hue parameters corresponding to a main hue; a luminance parameter calculation device which calculates luminance parameters in units of pixels; and a pattern light detecting device which detects pixels representing the pattern light. The pattern light position extracting device extracts the position of the pattern light based on the pixels representing the pattern light detected by the pattern light detecting device.

Abstract: Apparatus for quantitatively measuring the curvature and/or relative tilt of large surfaces wherein a small array of parallel laser beams, each separated by a known distance, reflect from the surface of a sample and fall upon a feedback controlled front-surface steering mirror to a detector that measures both the change in separation of the reflected beams and the spatial translation of the entire array on the detector. The sample surface is translated beneath or in front of the fixed laser array by means of a computer controlled stage or other apparatus to create a 1-dimensional line scan or 2-dimensional map of both bow and relative tilt of the sample surface. A computer-driven, feedback-controlled steering mirror compensates for varying sample tilt by precisely realigning the reflected laser array onto the detector as the sample is translated.

Abstract: A system and a method for optical characterization of a symmetric grating illuminated at off-normal incident angle are provided, where the plane of incidence is parallel to the grating lines. In this case corresponding positive and negative diffraction orders have the same intensity and phase. Several approaches for exploiting this symmetry are given. The first approach is a symmetric rigorous coupled wave analysis (SRCWA) adapted to the symmetric case, which accounts for N positive and N negative diffraction orders with M=N+1 space harmonics, without approximation. Various approximation methods are also given. Approximate versions of the RCWA (or SRCWA) can be developed by neglecting polarization coupling for small angles of incidence. A normal incident angle calculation can be used to approximate a situation with a small angle of incidence. Refinements to this approximation include revision of grating depth or refractive indices to improve accuracy.

Abstract: Methods and systems for calibrating media indexing errors in a printing device are provided. In one embodiment, the method comprises feeding a calibration media through a printing device, sensing the position of the media as it moves through the printing device, sensing positions of a media indexing component as the media moves through the printing device, determining media indexing position errors based upon the sensed positions, and calculating a compensation factor to be applied based upon the errors. In some embodiments, parameters of a line and/or other function are determined from the error data and the parameters are utilized to calculate a compensation factor. Moreover, in some embodiments, it is determined what range the data fits within, and a predetermined compensation factor is determined based upon the range.

Abstract: In transmitting/receiving an E-mail with a file attached to it, the contents of the attached file is to be displayed in a reception terminal irrespective of the file format of a file attached to the E-mail, the image size or the maximum number of colors in displaying the file contents. To this end, the accommodating capability in a reception terminal is verified based on a mail address in sending an E-mail with an attached file to a reception terminal. If the accommodating capability in the reception terminal is not matched to the attached file, the file is converted in keeping with the accommodating capability of the reception terminal, and the E-mail is sent with the so-converted file attached to it.

Abstract: A method is directed to using a multifunction printer to identify pages of a printed document that have a specified text string. The method comprises electronically converting, with the multifunction printer, a plurality of pages of the printed document to a plurality of electronic text pages corresponding to the printed pages. The multifunction printer electronically searches the plurality of electronic text pages to identify which electronic text pages include the specified text string. The multifunction printer then communicates the identified electronic text pages to the user.

Abstract: A digital printing system for producing prints in response to input digital images includes a digital printer and a plurality of computer processors. The plurality of computer processors includes one or more image-rendering units for rendering the input digital images to generate rendered digital images, wherein the image rendering is independent of specific characteristics of the digital printer. The plurality of computer processors further includes one or more image processors for processing the rendered digital images in accordance with one or more specific characteristics of the digital printer. The processed images are subsequently input to the digital printer to produce the prints. The computer processors can be dynamically assigned to be the image-rendering units or the image processors.

Abstract: An apparatus (10) for processing documents each represented by a document description (12) encoded in a page description language supportive of reusable data includes a page description language interpreter (14) that receives the document description (12) and parses the document description (12) into document components. An imager (16), communicating with the interpreter (14), creates image representations of received document components. A reusable document component repository (32) stores image representations derived from a plurality of processed documents. The reusable document component repository (32) communicates with the interpreter (14) and the imager (16) to supply those ones of the image representations corresponding to selected document components of the processed documents and to receive selected image representations created by the imager (16) during the processing of documents.

Abstract: A printing apparatus includes a generation unit for generating one page of a print image which is larger than one sheet of paper, and a printing unit for performing printing on one sheet of paper based on one page of the print image, which is larger than the paper and generated by the generation unit. The generation unit, based on an allocation number representing the number of pages to be allocated to one sheet of paper, performs clipping to remove a portion of the print data which can be printed by the printing unit to prevent the print image of each page which is not printed from deviating the image of each page, when a plurality of pages of print data printed on one sheet of paper are generated.

Abstract: A printer includes a processor. A replaceable ink cartridge includes a first integrated circuit (IC) containing print quality information and which is configured to be interfaced, in a releasable manner, to the processor. A replaceable printhead module includes a printhead which is configured to be interfaced, in a releasable manner, to the processor. The printhead is configured to print ink supplied from the ink cartridge using the print quality information.

Abstract: In an image scanning system which includes an image scanning apparatus for scanning an image using a solid-state image sensing element, and an image processing apparatus, the scanned image undergoes image correction. The image scanning apparatus informs the image processing apparatus of image scan characteristic data such as linearity characteristic data unique to itself. The image processing apparatus executes a correction process of an image scanned by the image scanning apparatus using the received image scan characteristic data.

Abstract: An image reading apparatus is provided which includes a contact image sensor comprised of a plurality of sensor chips arranged in series, an analog image processor for processing an analog image signal from the contact image sensor, a unit for conducting black shading correction for each pixel and a unit for conducting white shading correction for each pixel. The image reading apparatus further includes a unit for digitally monitoring a black offset value corresponding to each chip with respect to the signal that has been processed by the analog image processor and a unit for adding and subtracting a black offset variation amount for each chip in the previous stage of the unit for conducting black shading correction for each pixel, and corrects black offset based on an instruction of a control unit.

Abstract: In accordance with one embodiment, a method comprises querying, with a querying component, a print engine to ascertain one or more printmodes that are supported by the print engine, and, receiving, responsive to the querying, a list that describes printmodes supported by the print engine.

Abstract: In one embodiment, a raster image processor, which may be part of a printing device or configured as a separate device, includes a processor to parse a print ready file, a rasterizer to translate the parsed print ready file to an intermediate file, and a compressor to translate the intermediate file to an embedded bit-stream.

Abstract: A method for smooth trapping of a small graphical object, includes receiving from a trap generator the location of a trap pixel in a small object that should be changed in color; determining the width of the small object containing the trap pixel; comparing the width of the thin object with a trap threshold width; if the width of the thin object is less than the trap threshold width, adjusting the hue of the trap pixel according to a predetermined relationship; and applying a trap correction to the trap pixel according to the adjusted trap hue. The predetermined relationship may be a linear relationship that interpolates the trap hue monotonically (from the original trap hue to the original object hue) for object widths less than the trap threshold width. The method may be applied to small objects and small font text objects.

Abstract: The present disclosure relates to providing a user interface for the effective generation of differential gloss images. The user is instructed to indicate the base primary image data, and the desired gloss image data. This data may be displayed for verification and position adjustment by superimposition of the gloss image data upon the base image data. In an alternative, the placement information may be inferred from the position of originals upon the scanner or copier platen and the result may or may not be displayed. By selectively applying halftones with different anisotropic structure orientation characteristics to the base primary image data as directed by the desired gloss image data, a differential gloss image file or hardcopy may be provided.

Abstract: In a sheet-fed scanner capable of scanning multiple scan lines as a calibration standard for an image signal, a scanning module scans a document, which is fed across a scan region by a sheet-feeding mechanism, and a stationary calibration sheet in the scan region. The scanning module includes an image sensor, a lens and at least one reflecting mirror. An actuator actuates the reflecting mirror to enable the image sensor to sense a plurality of scan lines on the calibration sheet through the lens and the reflecting mirror in order to obtain a calibration standard for the image signal of the document. The calibration standard is adopted to calibrate an image signal of the document, and with this invention, it is possible to avert any flaws in image quality caused by the contaminated calibration sheet.

Abstract: An image reader is provided with a display changing signal input means for inputting a signal to change the display of the display panel, wherein the control unit is provided with a function of, when a display changing signal is inputted from the display changing signal input means and an image data of the operation keys described by closed areas in the layout of the operation keys written on the document is read by the image reading means, analyzing the image data and determining display operation keys to be displayed on the display panel in correspondence with the operation keys, a function of displaying the display operation keys on the display panel, a function of displaying a function selection screen used to allot functions to the display operation keys after the display operation keys are displayed on the display panel, and a function of allotting the functions selected from a function list on the function selection screen to the display operation keys.

Abstract: In a sheet-fed scanner capable of switching backgrounds, a scanning module scans a document, which is transported by a sheet-feeding mechanism across a scan region, and a stationary background component, which has a plurality of sections having different reflectivities and is disposed in the scan region. The scanning module includes an image sensor, a lens and at least one reflecting mirror. An actuator actuates the at least one reflecting mirror to enable the image sensor to selectively sense one of the sections of the background component as a scan background for the document through the lens and the at least one reflecting mirror.

Abstract: It is an object of the present invention to provide an excellent image reading apparatus that realizes miniaturization and reduces a total reading time at the time of reading a transparent original and, in addition, improves operability. In order to attain this object, since the image reading apparatus has a configuration in which a light source driving circuit section is disposed to overlap in the upward direction separating from an original mounting surface of a surface light emitting section, an area occupied by the light source driving circuit section and the surface light emitting section on a horizontal surface becomes small and miniaturization can be realized. In addition, since the light source driving circuit section and the surface light emitting section can be disposed in a position close to a hinge section altogether, the center of gravity of an FAU is moved to the hinge section side, and rotatability of the hinge section becomes easy and is improved.

Abstract: Disclosed in an optical scanning apparatus which includes a deflecting unit comprised of a rotary polygon mirror for deflecting a light beam radiated from a light source unit, and a scanning optical system for guiding the light beam deflected by the deflecting unit to a surface to be scanned. In the optical scanning apparatus, individual elements are set such that a diameter of a circumscribed circle of the rotary polygon mirror, the number of deflecting facets of the rotary polygon mirror, an incident angle of the light beam on the deflecting facet at the time when the light beam scans a scanning center, a maximum swing angle of the deflecting facet at the time when an effective scanning range is scanned, and a magnification of the scanning optical system in a sub scanning section can satisfy a predetermined condition, thereby reducing an unevenness of pitches due to a deflecting-facet fall of the rotary polygon mirror, and readily achieving a highly precise and fine image.

Abstract: A document platen. A support member supports an end portion of the document platen from below in a sub scanning direction. A sensor module has a first protruding portion protruding in the sub scanning direction. The sensor module includes a first sensor, and a second sensor being shorter than the first sensor in length and being housed into the first protruding portion. A transport unit transports the sensor module in the sub scanning direction. When the sensor module is transported to an end part in the sub scanning direction, the support member is housed into a space disposed at a side of the first protruding portion in a main scanning direction.

Abstract: An image reading apparatus includes an original resting glass sheet for resting allowing an original thereon, a support device for supporting an end portion of the original resting glass sheet, and a movable image reading unit for reading image information of the original, wherein the support device is provided with a cutout for preventing the support device from coming into contact with the image reading unit when the image reading unit moves outwardly beyond the end portion of the original resting glass sheet.

Abstract: There is provided a method of providing color matching between two output devices, which includes providing gradation matching between the two output devices, and providing color matching between the two output devices after providing the gradation matching.

Abstract: A discrimination medium 10a includes a first double layered body 101 having a right-handed circular polarization polymer cholesteric liquid crystal layer 11 and a left-handed circular polarization polymer cholesteric liquid crystal layer 12 which are stacked. The right-handed circular polarization polymer cholesteric liquid crystal layer 11 reflects a specific right-handed circular polarization light, and the left-handed circular polarization polymer cholesteric liquid crystal layer 12 reflects a specific left-handed circular polarization light. The discrimination medium 10a is applied to the article 30, and is viewed via a simple determination tool 20 having a filter 21 allowing only right-handed circular polarization light to pass therethough and a filter 22 allowing only left-handed circular polarization light to pass therethough.

Abstract: It is an object of the present invention to provide an optical multi-beam scanning device and an image forming apparatus which adopt a horizontal synchronization sensor and can suppress displacement in a horizontal scanning direction even when latent images are written on a surface to be scanned by a plurality off light beams tilting with respect to the surface to be scanned. In the optical multi-beam scanning device of the present invention, when the light beams are assumed to reach the surface to be scanned with the light beams not being folded, the horizontal synchronization sensor is tilted so as to output a horizontal synchronized signal when the light beams come to the same position on the surface to be scanned in the horizontal scanning direction. In another method, the horizontal synchronization sensor is not tilted, and the similar function is executed by setting a boundary position between a shielding portion and a non-shielding portion of a light shielding member provided on an upper stream side.

Abstract: An optical beam scanning device and an image forming apparatus are capable of suppressing adverse effect due to ambient temperature change on plural optical elements. The optical beam scanning device includes a single light deflector, a pre-deflection optical system which is entered a beam from a light source into the light deflector, and a post-deflection optical system which images a reflection beam from the light deflector on a scanned surface, and integrates at least one optical element of the pre-deflection optical system and at least one optical element of the post-deflection optical system. For example, the integrated optical element of the post-deflection optical system is an f? lens, and the optical element of the pre-deflection optical system is a correction lens which alleviates an influence by temperature change of the post-deflection optical system.

Abstract: An electrochromic mirror including a glass substrate, a transparent conductive film formed on the back of the glass substrate, an electrochromic layer formed on the back of the transparent conductive film, a reflection and electrode film formed on the back of the electrochromic layer in which the electrochromic layer and the reflection and electrode film are covered on the back thereof with an ion shielding oxide film, whereby the performance is stabilized and the productivity enhanced.

Abstract: Techniques for producing an optical broadband frequency sweep or chirp, include generating a narrowband frequency chirp and a frequency-shifted replica. The narrowband chirp has an optical carrier frequency, a pulse duration and a pulse bandwidth. A frequency-shifted replica is generated by frequency shifting the narrowband chirp by a frequency shift. Adding the frequency-shifted replica after a start of the narrowband chirp by a delay generates a broadband frequency chirp. Alternatively, the frequency-shifted replica is generated by frequency shifting a constant frequency pulse, and modulating the frequency-shifted pulse to generate narrowband chirps that are added to form the broadband chirp.

Abstract: A method for driving a light deflector the method includes turning over a direction of an electric field acting on the plate shape member, in an optional period. In the method, the light deflector deflects a beam incident on a light reflection area by displacing a plate shape member having the light reflection area with an electrostatic force. The light deflector includes a substrate, a plurality of control members, a fulcrum member, the plate shape member, and a plurality of electrodes.

Abstract: Improved apparatus and methods for spatial light modulation are disclosed which utilize optical cavities having both front and rear reflective surfaces. Light-transmissive regions are formed in the front reflective surface for spatially modulating light.

Abstract: A torsional hinge structure for supporting a functional surface such as a mirror is disclosed. The structure includes at least one torsional hinge extending between a functional surface such as for example, a mirror and an anchor pad such that the torsional or the functional surface can pivot around the torsional hinge. The device may comprise two torsional hinges or a single torsional hinge. However, the single torsional hinge or one of the dual torsional hinges will be elongated and include a permanent magnet mounting area to which is bonded a permanent magnet. The structure defines a bobbin area or portion underneath the enlarged area for mounting the drive magnet. A conductor is wound around the drive bobbin for forming an electromagnet, which generates magnetic forces that interact with the permanent magnet mounted on the torsional hinge to cause pivoting motion of the mirror or other functional device.

Abstract: A spatial light modulator includes a two-dimensional array of hexagonal mirror plates disposed in a honeycomb pattern over a substrate. Each of the hexagonal mirror plates is supported by one or more structural members. There is a gap between adjacent hexagonal mirror plates. The structural members are not located in the gap.

Abstract: Disclosed herein are novel electrophoretic displays and materials useful in fabricating such displays. In particular, novel encapsulated displays are disclosed. Particles encapsulated therein are dispersed within a suspending, or electrophoretic, fluid. This fluid may be a mixture of two or more fluids or may be a single fluid. The displays may further comprise particles dispersed in a suspending fluid, wherein the particles contain a liquid. In either case, the suspending fluid may have a density or refractive index substantially matched to that of the particles dispersed therein. Finally, also disclosed herein are electro-osmotic displays. These displays comprise at least one capsule containing either a cellulosic or gel-like internal phase and a liquid phase, or containing two or more immiscible fluids. Application of electric fields to any of the electrophoretic displays described herein affects an optical property of the display.

Abstract: A display system includes a transparent tapered plate comprising a first face, a second face, and a third face. The first face is substantially smaller than the second face and the third face. The display system also includes a row of tiltable mirror plates each comprising a reflective surface. Each of the mirror plates is configured to tilt to an “on” position to reflect incident light in an “on” direction or to tilt to an “off” position to reflect incident light in an “off” direction. An optical scanning system is configured to control the direction of the light reflected by the mirror plates in the “on” direction. The row of the tiltable mirror plates, optical scanning system and the tapered plate are configured to allow the light reflected by the row of mirror plates in the “on” direction to enter the tapered plate at the first face, be reflected by the second face, and produce a line of image pixels on the third face.

Abstract: The present invention relates to a system for detection and identification of airborne biological, chemical and/or nuclear threats such as toxins, spores, bacteria, and viruses in real time at distances from a few meters to several kilometers. Compact femtosecond terawatt laser technology is combined with spectroscopic and mathematical methods for spectral sensing of airborne warfare agents such as bio-aerosols. Trigger sensors and standoff devices based on mobile terawatt femtosecond laser systems are provided that may be placed at strategic monitoring locations. Furthermore, the invention relates to the propagation of airborne ultra-short, ultra-intense laser pulses giving rise to plasma channels (filamentation) producing white light supercontinuum ranging from the ultraviolet (UV), visible (VIS), near infra-red (NE) and middle infra-red (MIR).

Abstract: A high extraction efficiency laser system. The novel laser system includes a master oscillator for providing a laser beam, an amplifier adapted to amplify the laser beam, and an aberrator for aberrating the laser beam to prevent the formation of caustic intensity patterns within the amplifier. In an illustrative embodiment, the laser system also includes a depolarizer disposed between the master oscillator and the amplifier to reduce the contrast of speckle intensity patterns in the amplifier, and a mechanism adapted to rotate or otherwise move the aberrator to time-vary the aberrations in the beam in order to increase the spatial homogenization of saturation and extraction patterns in the amplifier. In a preferred embodiment, the coherence length of the beam is also shortened to reduce interference fringes in the amplifier.

Abstract: The invention pertains to optical fiber transmission systems, and is particularly relevant to optical transport systems employing Raman optical amplifiers. In particular the invention teaches an apparatus and method to provide initial tuning of a Raman pump module. In the present invention, improvements to Raman gain control are taught in order to provide for an advantageous Raman gain spectral profile.

Abstract: The present invention relates to an optical amplifier and, in particular, it relates to multistage optical amplification having a feature for compensating for the tilt that is generated when a signal having a plurality of optical wavelengths and the like according to a wavelength division multiplexing (WDM) method is amplified in a wide bandwidth. The multistage optical amplifier comprises: a plurality of optical amplifiers that are connected in a multistage manner; and a common control section for commonly controlling pumping light powers of said plurality of optical amplifiers, wherein said common control section includes: tilt detection means for detecting amounts of tilt of each of said plurality of optical amplifiers; and tilt cancellation means for controlling the pumping light powers of said plurality of optical amplifiers so that the amounts of tilt of each of the optical amplifiers detected by said tilt detection means cancel each other.

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Abstract: The invention provides an optical fiber amplifier which assures stable operation of a pump light source and efficiently makes use of residual pump power to achieve improvement in conversion efficiency. The optical fiber amplifier includes a rare earth doped fiber. Pump light from a pump light source is introduced into one end of the rare earth doped fiber by way of a first optical coupler, and residual pump light originating from the pump light and arriving at the other end of the rare earth doped fiber is applied to the other rare earth doped fiber amplifier or the loss compensation of a dispersion compensating fiber by Raman amplification.