Abstract: A light control unit that combines and outputs a plurality of light beams, including: a light emission section capable of outputting three or more light beams swept in wavelength within different wavelength ranges from each other; a wavelength combining section having wavelength selectivity, that combines and outputs at least two of the three or more light beams; and a control section that performs control in the light emission section, or upstream or downstream of the wavelength combining section in the optical path of the light beams to cause at least one light beam is outputted during a time period which is different from a time period in which another one or more light beams are outputted, thereby two or more light beams having different wavelengths from each other are combined and outputted at the same time.

Abstract: A low-cost homodyne laser interferometer probe of simple structure is provided which allows predetermined performance to be easily obtained by a simple adjustment, and a displacement measurement system using the same is also disclosed. The homodyne laser interferometer probe includes an optical fiber (1) for guiding light, a collimator lens (2) that receives the light from the optical fiber (1), a ¼ wavelength plate (3) that receives light from the collimator lens (2) and that converts the light from linearly polarized light into circularly polarized light, a beam splitter (4) for dividing light from the ¼ wavelength plate (3) into reference light and measurement light, a first focal lens (5) that receives the reference light from the beam splitter (4), a reflection mirror (6) for reflecting the reference light from the first focal lens (5), and a second focal lens (7) that receives the measurement light from the beam splitter (4).

Abstract: A technique is disclosed which offers an improvement in the performance of an atom interferometric (AI) sensor, such as one that is used in an accelerometer or a gyroscope. The improvement is based on the recognition that the AI-based device, which is associated with superior low-frequency performance, can be augmented with a conventional device having a superior high-frequency performance, as well as a wider frequency response, compared with that of the AI-based device. The disclosed technique combines acceleration measurements from the AI-based device, which is characterized by transfer function G(s), with acceleration measurements from the conventional device that have been adjusted by a complementary function, 1??(s), where ?(s) is an approximation of G(s). The conventional device has a considerably wider bandwidth than that of the AI-based device, and the quasi-unity transfer function of the conventional device makes possible the 1??(s) adjustment of the measurements provided by the conventional device.

Abstract: An alignment interferometer telescope apparatus comprises a coherent laser source, a first beam splitter, a reference spherical mirror, a light source, first and second reticles, and a second beam splitter. At an interference location within the apparatus, a reference laser wave and a test laser wave are allowed to interfere to produce a combined laser wave.

Abstract: A semiconductor laser gyro including a photodetector and a semiconductor laser 10 that emits first and second laser lights. The photodetector is disposed in a position where interference fringes are formed by the first and second laser lights. The semiconductor laser 10 includes an active layer as well as first and second electrodes 13 and 14 for injecting carriers into the active layer. The first laser light is one obtained through emission of a part of laser light (L1) that circulates on a polygonal path in the active layer. The second laser light is one obtained through emission of a part of laser light (L2) that circulates on the polygonal path in the opposite direction to the laser light (L1).

Abstract: A pulsed laser system includes a modulator module configured to provide pulsed electrical signals and a plurality of solid-state seed sources coupled to the modulator module and configured to operate, responsive to the pulsed electrical signals, in a pulse mode. Each of the plurality of solid-state seed sources is tuned to a different frequency channel separated from any adjacent frequency channel by a frequency offset. The pulsed laser system also includes a combiner that combines outputs from each of the solid state seed sources into a single optical path and an optical doubler and demultiplexer coupled to the single optical path and providing each doubled seed frequency on a separate output path.

Abstract: A measurement method for measuring a shape of a target using an interference pattern includes the steps of converting a first interference pattern into a first shape of the target (S103 to S105), obtaining a second interference pattern at a position where the target moves in an optical axis direction of the reference surface (S107, S108), unwrapping the second interference pattern after aligning a phase of the first interference pattern with a phase of the second interference pattern (S109), converting the unwrapped second interference pattern into a second shape of the target (S110), determining whether or not the first shape of the target coincides with the second shape (S111), and calculating the shape of the target by adding the integral multiple of a wavelength of the light source to the unwrapped second interference pattern if the first shape does not coincide with the second shape (S112).

Abstract: An apparatus for measuring surface topography of an object includes an optical arrangement capable of directing a first light beam at a surface of the object, providing a second light beam coherent with and spatially phase-shifted relative to the first light beam, and generating an interference beam from the second light beam and a reflection of the first light beam from the surface of the object. The apparatus further includes at least one line scan sensor for detecting and measuring the interference beam.

Abstract: The present invention relates to a method of sensing a disturbance along an optical link including the steps of: using a first interferometer arrangement connected to an optical source so as to generate pairs of signal copies, which signal copies of a given pair are temporally delayed relative to one another; transmitting the time-displaced signal copies from the first interferometer arrangement onto the optical link; receiving the time-displaced signal copies transmitted over the optical link; and, using a second interferometer arrangement to temporally recombine the received signal copies from a given pair so as to generate an interferometer signal, which interferometer signal is representative of environmental effects on the optical link.

Abstract: Various systems and methods for analysis of optical pulses are provided. In one embodiment, an optical system is provided having an optical axis. The optical system includes a two-dimensional diffraction grating positioned along the optical axis, and a spectral filter positioned along the optical axis after the two-dimensional diffraction grating. The spectral filter is angularly offset about a vertical transverse angle associated with the optical system. The diffraction grating is angularly offset about the optical axis relative to the spectral filter, and an optical capture device positioned after the spectral filter.

Abstract: Disclosed are an apparatus and methods for determining electric field characteristics of pulses. In one example, a method is provided in which an unknown pulse is propagated through a first optical fiber. A reference pulse is propagated through a second optical fiber. The unknown pulse and the reference pulse are directed out of the first and second optical fibers into a spectrometer. The unknown pulse and the reference pulse propagate along a pair of crossing trajectories through the spectrometer to form an interferogram. The electric field of the unknown pulse is determined by processing this interferogram.

Abstract: A device for performing polarization mode dispersion (PMD) measurements of an optical fiber is disclosed. The PMD measurement device employs a fixed analyzer method, and includes a tunable Fabry-Perot inferometer as the wavelength-selective element and an optical bandpass filter for spectrum calibration. A novel scanning algorithm, which performs multiple scans at different velocities, enables accurate PMD measurements, even of moving optical cable. The tunable Fabry-Perot interferometer is able to scan over a wide wavelength range and yet have a narrow linewidth, such that a wide range of PMD values can be measured.

Abstract: A probe is presented that includes a light source, a coherent fiber bundle, and a pattern selector. The pattern selector is disposed between the light source and the proximal end of the coherent fiber bundle. The pattern selector includes at least one patterned zone through which light from the light source passes to project at least one fringe set onto a surface. Each of the at least one fringe sets has a structured-light pattern. The probe further includes an imager for obtaining at least one image of the surface and a processing unit that is configured to perform phase-shift analysis on the at least one image. A method for projecting a plurality of fringe sets suitable for phase-shift analysis on a surface using a probe is presented.

Abstract: Methods and apparatus are provided for integrating various optical components onto a planar substrate using a single semiconductor material system to produce an accelerometer. A light beam is generated on the semiconductor optical accelerometer. The light beam is split to form two light beams using a multimode interference (MMI) coupler. One of the two light beams that is formed is directed towards a reference mirror and the other is directed towards a flexured mirror. The flexured mirror moves as a result of acceleration and thereby reflects the light beam with a different light beam characteristic. The light beams are combined by the MMI coupler to produce an interference light beam. A microprocessor measures acceleration based on the differences in light beam characteristics of the reflected light beams. Along the optical path light beam detectors measure various beam characteristics. The microprocessor accounts for characteristics measured by the detectors when computing acceleration.

Abstract: A ring-laser gyroscope system includes a ring-laser gyroscope (RLG) and at least one dispersive element optically coupled to the RLG's ring-shaped optical path. Each dispersive element has a resonant frequency that is approximately equal to the RLG's lasing frequency. A group index of refraction defined collectively by the dispersive element(s) has (i) a real portion that is greater than zero and less than one, and (ii) an imaginary portion that is less than zero.

Abstract: A phase-shifting interferometry (PSI) method and corresponding system including: (i) recording an interferogram for each phase in a sequence of phases between test light reflected from a test surface and reference light reflected from a reference surface, the test and reference light being derived from a common source, each interferogram corresponding to an intensity pattern produced by interfering the reflected test light with the reflected reference light, the interferograms defining an interferometry signal for each of different transverse locations of a cavity defined by the test and reference surfaces, each interferometry signal including a series of intensity values corresponding to the sequence of phases, with the difference between each pair of phases in the sequence defining a corresponding phase shift increment; (ii) calculating an initial phase map for the cavity based on at least some of the recorded interferograms; (iii) calculating an estimate for each of at least some of the phase shift increme

Abstract: A method is provided for measurement of dispersion or other optical and mechanical properties within a waveguide by inducing four-photon mixing at different locations within the waveguide by timing a pump signal to counter-collide with and abruptly amplify or attenuate one or both of a probe pulse and a signal pulse at each location. The measurement of the components of the resulting mixing signal created by each collision is used to calculate dispersion defined by the location at which the collision occurred. By combining the measurements from all of the locations, a spatial map of dispersion or other optical or mechanical properties within the waveguide can be generated.

Abstract: A phase-shifting interferometry (PSI) method and corresponding system including: (i) recording an interferogram for each phase in a sequence of phases between test light reflected from a test surface and reference light reflected from a reference surface, the test and reference light being derived from a common source, each interferogram corresponding to an intensity pattern produced by interfering the reflected test light with the reflected reference light, the interferograms defining an interferometry signal for each of different transverse locations of a cavity defined by the test and reference surfaces, each interferometry signal including a series of intensity values corresponding to the sequence of phases, with the difference between each pair of phases in the sequence defining a corresponding phase shift increment; (ii) calculating an initial phase map for the cavity based on at least some of the recorded interferograms; (iii) calculating an estimate for each of at least some of the phase shift increme

Abstract: A semiconductor ring laser gyro comprises: a semiconductor laser for emitting light from each of both ends thereof; a splitting means for splitting and guiding the light emitted from the semiconductor laser into two axis directions; a plurality of reflecting means for reflecting the light split and guided by the splitting means into the two axis directions; two optical circuits, in each of which the plurality of reflecting means cause the light to travel in a plane and to enter an end of the semiconductor laser opposite to the end from which the light is emitted; and a blocking means for blocking light traveling in one of the two optical circuits.

Abstract: The present invention is a tunable semiconductor laser for swept source optical coherence tomography, comprising a semiconductor substrate; a waveguide on top of said substrate with multiple sections of different band gap engineered multiple quantum wells (MQWs); a multiple of distributed feedback (DFB) gratings corresponding to each said band gap engineered MWQs, each DFB having a different Bragg grating period; and anti-reflection (AR) coating deposited on at least the laser emission facet of the laser to suppress the resonance of Fabry-Perot cavity modes. Each DFB MQWs section can be activated and tuned to lase across a fraction of the overall bandwidth as is achievable for a single DFB laser and all sections can be sequentially activated and tuned so as to collectively cover a broad bandwidth, or simultaneously activated and tuned to enable a tunable multi-wavelength laser.