Ssoct detects wavelengthresolved interference frin ges generated by a wavelength scanning laser. We present a characterization technique for coupled spacedivision multiplexed sdm amplifiers, that can measure the complex transfer matrix over the whole wavelength range of interest of an amplifier. Although this approach offers unrivaled precision, the periodic signal. Highaccuracy length metrology using multiple stage swept. Superresolved sweptwavelength interferometry using frequency estimation methods. Multiple wavelength interferometry mwi is a technique were the use of at least. The high signaltonoise ratios typical of sweptwavelength interferometry swi enable distance measurements to be superresolved with 2. Direct phase measurement interferometry and optical testing phasestepping and phaseshifting basic concept phase shifters algorithms phaseunwrapping phase shifter calibration errors. Building a sweptwavelength system requires a tunable laser source, the device under test, power sensors, and a dataacquisition system.
Sweptwavelength interferometry for sdm amplifier characterization. It is possible to change this amplitude by varying either the wavelength sweptfrequency interferometry, sihna 12 or the distance sweptdistance interferometry, mcclements 911. Newbury, and leo hollberg cavitymode wavelengths in air are determined by measuring a lasers frequency. Advances in sweptwavelength interferometry for precision. Dynamic absolute distance measurement by frequency sweeping interferometry based doppler beat frequency tracking model. Optical interferometry in astronomy 793 is resolved by an interferometer if the fringe contrast goes to zero at the longest baseline. These two beams are recombined by the beamsplitter to interfere. Estimated pdf of envelope amplitude sn at the passband central frequency fn 0 for different. A 780 nm diode laser sweptfrequency heterodyne facility is described and its use demonstrated for accurate determination of the optical path length of two stable fabryperot etalons. Sweptwavelength interferometric interrogation of fiber rayleigh. Typical interferometer the expanded beam exiting from the light source is divided by a beamsplitter into two beams.
Comprehensive comparison of axial length measurement with. In this work, we combine the sweptwavelength interferometry swi with a. Wavelengthtuning interferometry of intraocular distances f. Mcleod, superresolved sweptwavelength interferometry using frequency estimation methods, opt.
Characterization of coupledcore fiber amplifiers using swept wavelength interferometer juan carlos alvaradozacarias, charles mattebreton, roland ryf, nicolas k. Absolute distance metrology using frequency swept lasers oxford. Highspeed optical coherence tomography system using a. In this paper, a sweptwavelength interferometry swi based dofs technique is used to monitor the fatigue in a. We describe the use of swept wavelength interferometry for distributed fiberoptic strain and temperature sensing in single mode and gradient index multimode fiber. Wyant this paper describes a method to enhance the capability of twowavelength phaseshifting interferometry. The method is used to measure strain in a fourstrand multimode cable under twist. Swept wavelength interferometry allows measurement of the polarization resolved complex transfer function h. The sweptwavelength method for highresolution wavelength. Principles of interferometry interferometry primer evolution of solarmass stars eso garching, march 25, 2010 chris haniff astrophysics group, cavendish laboratory, university of cambridge, uk 1 march. Swept frequency acoustic interferometry remediation weekly. One beam is reflected from the reference mirror, and the other one from the sample.
Optical setup for two wavelength superheterodyne interferometry. Enhancing the resolution limits of spectral interferometric measurements with sweptwavelength interrogation by means of a reference interferometer nikolai ushakov,1, alexandr markvart,1 leonid liokumovich1 1 department of radiophysics, st. The spectral phase response of a reference gas cell in the vicinity of. They are conveniently divided into two main classes.
Sweptwavelength interferometric interrogation of fiber. The frequencysampling method is widely used to accommodate nonlinear electromagnetic source tuning in sweptwavelength interferometric techniques, such as optical frequency domain. One beam is reflected from the reference mirror, and the other one. Request pdf vibration tolerant swept wavelength interferometry we describe a vibration tolerant coherent interferometer. The high signaltonoise ratios typical of sweptwavelength interferometry.
Request pdf superresolved swept wavelength interferometry using frequency estimation methods the high signaltonoise ratios typical of swept wavelength interferometry swi enable distance. Osa characterization of coupledcore fiber amplifiers. Vibration tolerant swept wavelength interferometry. Characterization of coupledcore fiber amplifiers using swept. Insights into sweptwavelength characterization of passive fiberoptic components. Osa high resolution distributed strain or temperature. Mcleod originally developed for radar applications in the 1950s, swept wavelength interferometry swi at optical wavelengths has been an active area of research. The rayleigh scatter complex amplitude can be fourier. Sweptwavelength interferometry allows the rayleigh scatter amplitude and phase to be sampled with very high spatial resolution 10s of microns. Fatigue damage monitoring of a composite step lap joint. Dimensional metrology and frequency sweeping interferometry. Multiple wavelength interferometry mwi is a technique were the use of at least two different wavelengths allows the generation of a synthetic wavelength much longer than the two individual optical wavelengths, actually increasing the nonambiguity range nar for interferometry dandliker et al.
This paper reports the optimization possibilities of some nonlinear sources of limitations in the resolution and accuracy of an absolute distance interferometry setup using an external cavity laser. A method, system and apparatus for obtaining a parameter of interest from a plurality of sensors in a fiber optic cable deployed in a wellbore are disclosed. A straightforward means for manual polarization control. Interferometry introduction interferometers are devices employed in the study of interference patterns produced by various light sources. Wavelengthtuning interferometry of intraocular distances. Petersburg state polytechnical university, polytechnicheskaya, 29, 195251, st. Interferometry is a family of techniques in which waves, usually electromagnetic waves, are superimposed, causing the phenomenon of interference, which is used to extract information. Sweptwavelength interferometric analysis of multiport. Dynamic absolute distance measurement by frequency. Kulhavy we describe basic principles of wavelengthtuning interferometry and demonstrate its.
Direct phase measurement interferometry and optical testing. This invention relates generally to a system and method for detecting flashback events in a combustor of a gas turbine. A schematic illustration of a sweptwavelength interferometer for performing range. Influence of nonlinearities in wavelengthswept absolute. Pdf on may 1, 2012, alexandre cabral and others published dimensional. Fontaine, haoshuo chen, steffen wittek, hirotaka sakuma, takafumi ohtsuka, tetsuya hayashi, takemi hasegawa, sophie larochelle, and rodrigo amezcuacorrea. Wavelength references for interferometry in air richard w. Multiwavelength interferometry for length measurements using. Superresolved sweptwavelength interferometry using. Moore has been approved for the department of electrical, computer, and energy engineering robert r.
Astrophysics group, cavendish laboratory, university of. The broadsweepers series is a new family of tunable semiconductor lasers intended for applications that require fast and precision wavelength tuning with high sweeptosweep reproducibility of the. As motivated in the last paragraph, this occurs when the angular. The oa2000 is a biometer based on fourier domain technology by light interference using a sweptsource laser with a wavelength of 1,060 nm. At a given optical wavelength, an interference signal varies as a sinusoidal function of distance with a period equal to the wavelength. Absolute distance measurement using frequency sweeping. Coherent absolute distance interferometry is one of the most interesting techniques for length metrology. In frequency sweeping interferometry fsi, measurements are made without ambiguity, by using a. Advances in swept wavelength interferometry for precision measurements thesis directed by associate professor robert r. An approach for compensating the influence of the interrogator noises on the readings of interferometric sensors, interrogated by means of spectral interferometry with wavelength tuning is proposed.
The length result from one synthetic wavelength is typically used to determine the fringe order of the next shorter synthetic wavelength. A key component of an ssoct system is the light source. Osa superresolved sweptwavelength interferometry using. Pdf dimensional metrology and frequency sweeping interferometry. Optical coherence tomography oct is an imaging technique that uses lowcoherence light to capture micrometerresolution, two and threedimensional images from within optical scattering media e. Advances in sweptwavelength interferometry for precision measurements written by eric d. Swept wavelength laser s3 key features custom oem con. Originally developed for radar applications in the 1950s, sweptwavelength interferometry swi at optical wavelengths has been an active area. Known as swept frequency acoustic interferometry sfai, the technology utilizes high frequency sound waves to analyze and detect preprogrammed contaminants in water systems through metal, glass. Argos uses a 1,060 nm wavelength sweptsource technology and records a twodimensional oct image from the corneal apex to the macula. Multiplewavelength phaseshifting interferometry yeouyen cheng and james c. Us8592747b2 programmable filters for improving data.
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