Abstract: An interferometric environmental monitoring system having an active beam and a reference beam, each following an optical path, a detector system including a detector assembly, a pair of reflecting elements, the first reflecting element receiving the active beam and reflecting it, the second reflecting element receiving the reference beam and reflecting it. The reflected active and reflected reference beams are recombined into a recombined beam, which is directed to the detector assembly. The detector assembly monitors the central fringe of an interference pattern formed by interference when combining the active and the reference beams and providing an output signal related to the movement of the central fringe. The output signal being utilized to provide a signal representative of a condition which measurably affects the active beam.

Abstract: A high efficiency, broad bandwidth, volume holographic element for diffraction windows. This holographic element is fabricated so that it can passively track and diffract solar radiation throughout the course of a day. Such a hologram can effectively illuminate the interior of a building or room with sunlight. This invention can reduce both lighting costs and the cooling costs associated with generating artificial light.

Abstract: The Index Interferometric Instrument is a highly accurate instrument which can be utilized to measure the index of refraction, the dispersion, and the index profile of materials. The instrument provides the data necessary to measure the index of refraction of materials to five significant figures. The index profile can be measured at any chosen wavelength without any sample preparation. The instrument utilizes a 10 nm to a 400 nm bandwidth light source and a light source with a bandwidth of less than 10 nm in combination with an interferometer. Each light source creates interference patterns from the sample and a reference mirror which can be used to accurately calculate the index of refraction of an entire sample at any given point on the sample.

Abstract: A fiber optic cable connector for coupling together a pair of optical fibers having a pair of fixtures, each of the fixtures securing therein a respective optical fiber and having a magnification lens optically aligned with the end of the optical fiber. The lenses and fibers are so positioned relative to each other so as to focus a magnified or enlarged image of the end of each of the fibers to a predetermined position. A fastening means is utilized to removably attach the fixtures together in such a manner that the positions of the enlarged images of the fibers overlap thereby achieving excellent coupling of the adjacent fiber optic ends.

Abstract: A fiber Fourier spectrometer having a focusing element, a beamsplitter, a pair of monomode optical fibers, a block of electro-optic material defining a pair of optical paths and means for controlling the effective length of one of the optical paths. A source of electromagnetic radiation is focused through and reflected by the beamsplitter into the pair of monomode fibers, respectively, and from there to the respective optical paths within the electro-optic block of material. The outputs of the two optical paths are combined and received by an intensity detector. Varying the effective path length of one of the optical paths alters the phase of the beam passing therethrough. Because the source of electromagnetic radiation has different wavelengths, the spectral components of the source are phase retarded by different amounts as they pass through the electro-optic material and can therefore be analyzed by a conventional Fourier spectroscopy technique.

Abstract: An optical correlator having a series of optical elements necessary for providing the comparison or correlation of incoming optical signals and for providing a readout beam representive of the correlation between the input signals; and a detection system which is capable of rapidly and reliably detecting intensity peaks in the readout beam. These intensity peaks establish the actual correlation between the optical input signals. The detection system incorporates therein a pair of optical fibers, one of which having associated therewith an electro-optic component for effectively varying the length of that fiber. By varying the effective length of one of the fibers, an intensity detector can provide an output of the intensity peaks necessary in making the actual correlation determination between the optical input signals.

Abstract: An optical electromagnetic radiation detector having a probe for receiving nearby electromagnetic radiation. The probe includes a loop antenna connected to a pair of transparent electrodes deposited on the end surfaces of an electro-optic Fabry-Perot interferometer. When the loop antenna picks up the presence of electromagnetic radiation, a voltage will be developed across the crystal of the electro-optic Fabry-Perot interferometer thereby changing the optical length of the interferometer. A beam of light from a remote location is transmitted through an optical fiber onto the Fabry-Perot interferometer. The change in optical length of the Fabry-Perot interferometer alters the intensity of the beam of light as it is reflected from the Fabry-Perot interferometer back through the optical fiber to the remote location. A beamsplitter directs this reflected beam of light onto an intensity detector in order to provide an output indicative of the variations in intensity.

Abstract: An interferometric system for general use to measure the angular relationship of two surfaces of the same object, or of different objects, or the relative angular change of one surface with respect to another. This device uses coherent light, a set of mirrors aligned as a Ludman Interferometer, and a reference pair of mirrors with a well known fixed angle similar to that of the angle of the sample pair to be measured. In preferred embodiments, the fixed angle mirror pair has a fine tilt adjustment to facilitate the interpretation of the output fringe pattern.

Abstract: A fiber stellar interferometer having a pair of adjustably movable focusing lenses, a pair of monomode optical fibers, a block of electro-optic material defining a pair of optical paths, means for controlling the effective path length of one of the optical paths and an intensity detector. Electromagnetic radiation emanating from a source, such as a star, is received at two separate locations by the focusing lenses which direct this electromagnetic radiation into two separate beams which are focused into each of the pair of monomode fibers, respectively. The monomode fibers direct these two beams into respective optical paths within the electro-optic block of material. The outputs from the two optical paths are combined and received by the intensity detector. Varying the effective path length of one of the optical paths alters the phase of the beam passing therethrough. As a consequence thereof the intensity of the output received by the detector varies accordingly.

Abstract: A fiber optic directional coupler having a holographic element incorported therein. A single optical signal impinges on the holographic element and is separated into a plurality of individual signals which are coupled to a plurality of individual optical fibers. Only a fraction of the incident electromagnetic radiation incident on the holographic element is transmitted to any one of the plurality of fibers. Reversing the direction of the radiation causes all the energy emanating from the combined plurality of fibers to be coupled to the single receiving fiber.

Abstract: A holographic coupler for fiber optic systems having a holographic element utilized in conjunction with an optical source and an optical fiber in order to direct and couple the beam emanating from the optical source into the fiber. The holographic element, source and optical fiber have the same relative position with respect to each other as (1), a photosensitive medium, (2) a means for sizing and shaping a beam of temporally and spatially coherent radiation to the same geometry as the optical source before the beam impinges upon the photosensitive medium, and (3) the focal point of a converging beam of temporally and spatially coherent radiation impinging upon the photosensitive medium during the making of the holographic element used with the coupler.

Abstract: An improved method of manufacturing holographic elements for fiber and integrated optic systems in which a spatially and temporally coherent beam of electromagnetic radiation is divided into two beam paths. The first beam path and the second beam path are optically aligned with each other so that the beams impinge upon a photosensitive medium and interfere therein. Additionally, a spherically diverging wavefront is formed within one of the paths while an identical polarization is maintained in the beams of the two beam paths. By appropriate processing of the photosensitive medium a holographic element is formed which is substantially improved over holographic elements for fiber and integrated optic systems produced by manufacturing techniques of the past.

Abstract: A multiplexer/demultiplexer having a holographically formed reflective grating incorporated therein. In operation as a demultiplexer a single signal having a plurality of wavelengths impinges upon the holographic reflective grating in an appropriate manner and is separated into a plurality of signals, each being of a different one of the wavelengths. In the multiplexing mode of operation, a plurality of signals, each being of a different wavelength impinges upon the holographic reflective grating in an appropriate manner and emerges therefrom as a single signal having all of the different wavelengths.

Abstract: A multiplexer/demultiplexer having a holographic element made using a single exposure of a photosensitive medium incorporated therein. In operation as a demultiplexer a single signal having a plurality of wavelengths impinges upon the holographic element in an appropriate manner and is separated into a plurality of signals, each being of a different one of the wavelengths. In the multiplexing mode of operation, a plurality of signals, each being of a different wavelength impinges upon the holographic element in an appropriate manner and emerges therefrom as a single signal having all of said different wavelengths.

Abstract: An interferometer optical system for general use to measure optical parallelism or relative rotational or joint translational positions of the two spaced subject mirrors uses coherent light split into two beams which are directed, one normal to one of the two mirrors and the other normal to the other of the two mirrors. The reflections of these two beams are then superimposed on a target which reveals a light interference pattern indicative of the parallelism or relative rotation or joint translation of the two mirrors. In preferred embodiments, in order to compensate for the mutual tilt of the subject mirrors with respect to the plane of the beams incident thereon, the path of one of the beams to and from the subject mirror includes a corner mirror, or retrodirective mirror, and the path of the other beam includes at least one adjustable mirror.