Abstract: The method is used for the interferometric measurement, in particular for the interferometric absolute measurement, of non-rotationally symmetric wavefront errors on a specimen. The specimen can in this case be brought into a plurality of rotational positions, at least one measurement result being determined in each of the rotational positions. A mathematical evaluation of all measurement results is carried out in conclusion. The measurement is carried out in at least two measurement series (M, N). The measurement results (M1 . . . Mm, N1 . . . Nn) of each of the measurement series (M, N) are respectively determined in mutually equidistant rotational positions of the specimen. Each of the measurement series (M, N) comprises a specific number m, n of measurements. The individual numbers m, n are natural and mutually coprime numbers.

Abstract: The invention concerns an interferometric optical block for Fourier Transform spectrometers having three planar nominally parallel surfaces with the two outer surfaces adapted to act as beam reflectors for internal light and the third surface in operation acting as a beam splitter and beam combiner, the optical block having an input portion by means of which an input beam of light to be analysed can be input so as partially to pass through said third surface to be internally reflected by one of said outer reflectors, and partially to be reflected by said third surface so as then to be internally reflected by the other of said outer reflectors whereby light internally reflected by said outer reflectors is combined at said third surface to produce an exit beam, and wherein said outer surfaces have an inclination with respect to one another so as to make a variation in path lengths in the light forming the exit beam so as to generate an interference fringe field.

Abstract: The invention comprises a system and method for reducing a shot noise component of the Angle Random Walk Noise in a fiber optic sensor by providing a first optical amplifier prior to the photodetector of the sensor to increase the power seen at the detector. An optical amplifier and second detector may be provided to detect a source sample, which can be useful in reducing RIN noise. Optical isolators may be added at the optical amplifiers to prevent rear facet emissions from the optical amplifiers from affecting sensor signals. A coupler with an isolator, amplifier and detector may be provided to receive a sample of the facet emissions from the first optical amplifier, which may be subtracted from the sensor signal at the detector so as to eliminate the facet emissions from the sensor signals. Polarizers may be provided prior to each detector to further eliminate emissions.

Abstract: In the measurements of optical characteristics, such as measurements of group delay using an interferometric system, vibration noise can be at least partially offset by providing corrections on the basis of detecting light patterns that are indicative of the vibration noise. In each embodiment, light beams propagating through first and second paths are combined to form an interference signal, which is analyzed to provide the basis for the adjustments.

Abstract: A signal/vibration detecting technique employs a simple structure to identify a target optical fiber among many and carry out a bidirectional conversation through the target optical fiber. First ends of optical fibers (202A, 202B), one of which is a target optical fiber, are connected to an optical transceiver (201). Second ends of the optical fibers are connected to each other to form a loop. A local unit (203) is installed at the loop. The local unit vibrates the loop, and the optical transceiver emits lights so that the lights are oppositely propagated through the loop. The propagated lights are coupled together so that they interfere with each other. In the intensity of the interfering lights, a change corresponding to the vibration is detected to identify the target optical fiber. Once the target optical fiber is identified, it is used to carry out a conversation between the optical transceiver and the local unit.

Abstract: Methods and apparatus for chromatic dispersion compensation are provided. The apparatus includes a Gires-Tournois etalon, an optical beam separator, a GTE controller, an optical distortion analyzer, and a feedback controller.

Abstract: A modular interferometric imaging system includes a sensor array that senses a physical parameter and provides a plurality of first sensor array output signals indicative thereof. An analog die receives the plurality of first sensor array output signals, and digitizes and modulated each of the first sensor array signals to provide a plurality of digitized signals. A digital die receives the plurality of digitized signals to provide a plurality of received digitized signals, and demodulates the plurality of received digitized signals to provide a plurality of demodulated digitized signals indicative thereof. A processor receives and processes the demodulated digitized signals to provide an imaging system output signal.

Abstract: A retarder includes a birefringent film embedded in an adhesive between two plates. The adhesive is index matched to the birefringent film.

Abstract: An optical transmission system is provided by preparing a two-photon transition medium where efficiency of two-photon transition does not depend on polarization; splitting an optical pulse to be measured into a probe optical pulse and a gate optical pulse by a polarization independent beam splitter; after adding variable delay time to this gate optical pulse, entering the probe optical pulse and the gate optical pulse into a highly efficient two-photon absorption medium so that both of the pulses cross each other, and thereby generating an optical gate function; resolving a spectrum of the transmitted probe optical pulse, and detecting the spectrum by a photodetector; and measuring intensity of electric-field absorption of the probe optical pulse as a function of delay time and a frequency.

Abstract: An apparatus includes a multi-axis interferometer for measuring changes in a position of a measurement object. The interferometer is configured to receive a progenitor input beam, direct a first angle-measuring beam derived from the progenitor input beam to make a pass to a first point on the measurement object, direct a second angle-measuring beam derived from the progenitor input beam to make a pass to a second point on the measurement object, and then combine the angle-measuring beams to produce an angle-measuring output beam, wherein each angle-measuring beam makes only a single pass to the measurement object before being combined to form the angle-measuring output beam. The interferometer is further configured to direct another set of beams derived from the progenitor input beam along different paths and then combine them to produce another output beam comprising information about changes in the position of the measurement object.

Abstract: To accurately measure the position and posture of a stage apparatus used in an exposure apparatus or the like, the Z position and displacement of a top stage (27) are measured using as a reference a lens barrel support (35) independently of the top stage in terms of vibrations by an interferometer system which includes a projection optical system (34) for projecting a pattern formed on a master onto a substrate, stages (27, 31, 40) capable of moving with respect to the projection optical system (34) while holding the substrate or master, and a lens barrel support (35) that supports the projection optical system (34), and which uses a Z measuring mirror (30) that is arranged on a Y stage (31) and has a reflecting surface almost parallel to the XY plane, and a Z interferometer (25) arranged on the Y stage (31).

Abstract: A manifold for providing the simultaneous processing of a plurality of laser block assemblies. In one embodiment, the manifold includes a hollow passage formed along the length of the manifold, and a plurality of passages extending between the hollow chamber and the exterior of the manifold. A laser block assembly is mounted to each of the plurality of passages of manifold. The assemblies can be arranged in a flat or parallel spaced arrangement relative to each other, and are mounted to the manifold with a fitting that is adapted to be easily severed after processing of the assemblies is completed. The manifold is mounted to a station of a processing tool, and a plurality of processing applications are performed on the plurality of laser block assemblies in a simultaneous fashion.

Abstract: A polarization independent optical spectrum analyzer comprises an inherently polarization sensitive angle-tuned filter element and polarization-maintaining multi-pass optics for directing a light beam to and fro through the tunable filter element while maintaining its linear state of polarization. The optical spectrum analyzer comprises such a tunable optical filter in combination with a polarization control unit for decomposing a light beam for analysis into first and second beams having mutually orthogonal states of polarization (SOPs) and then adjusting one or both SOPs so that they are parallel to each other and to one of the principal axes of the angle-tuned filter which selects different wavelengths of the first and second light beams. The first and second light beams are passed through the filter repeatedly by multi-pass polarization-maintaining optics.

Abstract: A tilt compensator and delay element for use in an interferometer. The interferometer can be a scanning or a non-scanning interferometer. For example, the interferometer can be a Michelson-Morley interferometer or a Mach-Zehnder interferometer having a scanning mirror. The tilt compensator and delay element removes the tilt effects of the scanning mirror in two axes. The interferometer receives light and passes the light through a beam splitter. The light passed through the beam splitter is reflected by at least two mirrors. The beam splitter and the mirrors are positioned in a first plane. The tilt compensator and delay element of the present invention is provided with an odd number of mirrors. The odd number of mirrors includes at least three mirrors. For example, the odd number of mirrors in the tilt compensator and delay element can include three mirrors, five mirrors, seven mirrors, nine mirrors, etc.

Abstract: A fiber optic monitor that utilizes optical phase interferometry to monitor a patient's vital signs such as respiration, cardiac activity, blood pressure and body's physical movement. The monitor, which is non-invasive, comprises an optical fiber interferometer that includes an optical fiber proximately situated to the patient so that time varying acousto-mechanical signals from the patient are coupled into the optical fiber. Responsive thereto, the interferometer generates a time-varying optical intensity resulting from the interference of optical signals, which are detected at a photo-detector. A signal processor coupled to the optical detector provides one or more processed output signals indicative of the vital functions. The monitor system has broad applicability, from routine monitoring of infants at home to detection of apnea, arrhythmia, blood pressure and trauma.

Abstract: A spectrometer may include a radiant source configured to emit radiation and an optical amplifier configured to amply the radiation emitted by the radiant source to produce amplified radiation. A number of optical elements may be configured to produce an interference pattern from the amplified radiation. A detector may detect the interference pattern and generate data from the interference pattern. A processor may be configured to measure one or more from the data.

Abstract: The present invention concerns an interferometric measurement apparatus for wavelength calibration, having a laser light source (1), a detector (2), and an interferometer (3), the laser light source (1) emitting light of at least one wavelength, the interferometer (3) separating the light of the laser light source (1) into two sub-beams (4, 5)—a reference beam (4) and a measurement beam (5)—and combining the sub-beams (4, 5) again after at least one reflection at one reflection means (6) each, and the path length difference between the reference beam (4) and measurement beam (5) defining a constant wavelength calibration distance. In order to increase the measurement accuracy and reduce measurement errors, the measurement beam distance can be extended, but without causing problems in terms of manufacture, assembly, and/or alignment.

Abstract: A method and system for calibrating an interferometric optical network analyzer is disclosed. Specifically, a plurality of interferometric measurements for a control optical element using first polarized lightwaves of a first amplitude and second polarized lightwaves of a second amplitude are received in accordance with the invention. Next, a calibration result is derived using the plurality of interferometric measurements in accordance with the present invention. With this calibration result, the optical properties of a device under test (DUT) measured using the first polarized lightwaves of the first amplitude and the second polarized lightwaves of the second amplitude can be determined with reduced uncertainty due to intrinsic optical characteristics of the interferometric optical network analyzer.

Abstract: The present invention relates to determination of a property of an optical device under test, e.g. the group-delay of the optical device under test, by: tuning an optical frequency &lgr; of an optical beam, deriving a dependency of the optical frequency &lgr; of the optical beam over a first time period t, deriving a dependency of the optical property of the device under test over a second time period t+&Dgr;t, synchronizing the time dependency of the optical frequency &lgr; of the optical beam with the time dependency of the optical property of the device under test, and deriving the frequency dependency of the optical property of the device under test from the synchronized time dependencies.

Abstract: A profiling method compensates for phase changes associated with the presence of multiple or varying material in the area to be measured. The profiling method measures at least a portion of the height profile of the area of interest. The phase of the different materials in the region are also obtained and used to generate a correction factor. Depending on the type of material in the region of interest, the correction factor may be the material specific phase difference of the materials in the region, e g., when at least one of the materials is opaque to the wavelength of light used to measure the height profile, or the relationship between the thickness and phase of the material for a desired thickness range, e.g., when one or more of the materials is transparent to the wavelengths used to measure the height profile. The correction factor is then used to correct and/or convert the measured phase profile to an actual height profile.