We report on low coherence, nearinfrared reflectometry applied to optical fibres, waveguides, and coupling devices to detect the echoes due to reflective propagation defects and measure their. A birefringentfiberbased dualchannel optical lowcoherence. Low coherence, highresolution optical reflectometry for fiber length measurement by jerome thomas b. In 1999, carl zeiss meditec ag introduced an optical biometry unit based on partial coherence interferometry pci, the iolmaster. Photoncounting optical coherencedomain reflectometry. Optical lowcoherence reflectometer for differential phase. Comparison of a new optical biometer and a standard. Osa polarizationsensitive lowcoherence reflectometer for.
Optical coherence tomography oct is an imaging technique that uses low coherence light to capture micrometerresolution, two and threedimensional images from within optical scattering media e. Optical low coherence reflectometry olcr is a whitelight interference technique. Optical low coherence domain reflectometry olcr has proven to be very effective for the measurement ofsmall closelyspaced optical reflections. Time domain reflectometry, a technique originally used in diagnosing cable. The low coherence reflectometer with the proposed optical delay line can perform a rapid scanning imaging and two dimensional. An otdr is the optical equivalent of an electronic time domain reflectometer. The analysis of the attenuation rate of the low coherence reflectometer signal depending on the probing depth provides additional information for the identification of skin morphologic changes and the analysis of the effect of immersion agents on the biotissue optical properties. Optical lowcoherence reflectometry of efficient bragg. Choosing the right optical time domain reflectometer otdr. Determination of birefringence and absolute optic axis orientation using polarizationsensitive optical coherence tomography with pm fibers jun zhang, shuguang guo, woonggyu jung, j. The aim of this study was to compare measurements using a new optical low coherence reflectometry olcr biometer oa2000 and the gold standard partial coherence interferometry pci. The deve loped measurement system is a combination of a profilometer and a tomographic imaging device, which makes the construction versatile and applicable in several paper measurement applications. Osa polarizationsensitive lowcoherence reflectometer.
Lowcoherence reflectometry and speckle polarimetry in the. Methods a prospective cohort study of 224 eyes of patients planned for cataract surgery was conducted in the period from january 2009 until july 2009. Optical low coherence reflectometer for differential phase. As shown in the diagram at left, a wideband optical light source is launched into a beam splitter and divided into. Optical lowcoherence reflectometry olcr is a technique based on interferometry which is design to detect and localize reflectorsl. Angleresolved low coherence interferometry alci is an emerging when. Small volumes located at the inside of the sample can be studied individually and with a high sensitivity. Lowcoherence, highresolution optical reflectometry for fiber length measurement by jerome thomas b. Differentiation of ex vivo human breast tissue using. Oct 17, 2016 biometry data and accurate intraocular lens iol calculations are very important in achieving the desired refractive outcomes. Twentytwo patients hospitalized at our eye clinic undergoing cataract surgery were. However, the envelopes of the interferograms are usually considered asthe. Optical lowcoherence reflectometry for nondestructive.
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. Scan speeds of 40 mms are achieved with a dynamic range of 90 db and a spatial resolution of 17 gm. The device is insensitive to the rotation of the sample in the plane perpendicular to ranging. Comparison of a new optical biometer and a standard biometer. A new optical low coherence reflectometry device for. The new haagstreit lenstar ls 900 measures all of the above parameters and additionally retinal thickness in the optical line utilising optical low coherence reflectometry olcr technology in a. Optical delay line for rapid scanning lowcoherence. Phasesensitive optical lowcoherence reflectometry for the detection of analyte concentrations kirill v.
Optical lowcoherence domain reflectometry olcr has proven to be very effective for the measurement ofsmall closelyspaced optical reflections. A generalized approach to optical lowcoherence reflectometry. The optical lowcoherence reflectometer olcr is a very powerful tool to characterize optical fibres and integrated optical components. An optical low coherence reflectometer is presented that uses a fiber michelson interferometer with a rotating cube to generate rapid depth scans at a high repetition rate. To evaluate optical ocular components in patients with pseudoexfoliation syndrome using optical low coherence reflectometry. The technology shows promise as a clinical tool for in situ detection of dysplastic, or precancerous tissue. A birefringentfiberbased dualchannel optical lowcoherence reflectometer capable of differential phase measurement is described. The eyes were in focus when the instrument head was approximately 6.
This thesis describes the applic ation of low coherence interferome try lci and optical coherence tomography oct in pape r measurements. Highresolution reflectometer aq7410b the aq7410b is a highresolution optical lowcoherence reflectometer based upon a michelson interferometer. Optical low coherence reflectometry for nondestructive process measurements summer lockerbie randall, anatol m. New mode for measuring axial length with an optical low. Oct 18, 2011 optical coherence tomography oct is a noninvasive high resolution optical imaging technology based on interference between signal from an object under investigation and a local reference signal. The lenstar was focused and aligned using the image of the eye on the computer monitor while the patient fixated on a flashing red light. In vivo pachymetry in normal eyes of rats, mice and. Sensitivity advantage of swept source and fourier domain.
Extendedrangeopticallowcoherence reflectometryusinga. Optical low coherence reflectometry olcr is applied to the precise characterization of bragg gratings in optical fibers. Birefringence measurement of the retinal nerve fiber layer. New developments find, read and cite all the research you need. However, this is a very complex setup and in addition to. New mode for measuring axial length with an optical lowcoherence reflectometer in eyes with dense cataract.
In contrast, optical techniques such as optical coherence tomography oct, partial. Optical delay line for rapid scanning lowcoherence reflectometer. Boppart1,2,3,4, 1beckman institute for advanced science and technology, 405 n mathews avenue, urbana, il 61801, usa 2department of electrical and computer engineering, 306 n wright street. Optical lowcoherence reflectometry olcr is a whitelight interference technique.
We present theoretical and experimental results which. Pdf a new optical low coherence reflectometry device for ocular. Reflectometry ocdr, optical low coherence reflectometry olcr, and. As shown in the diagram at left, a wideband optical light source is launched into a beam splitter and divided into two. The experimental results are in good agreement with the theoretical predictions of the path length variation model. It uses optical lowcoherence reflectometry olcr with a 820 nm laser. A swept source polarizationsensitive optical coherence tomography sspsoct instrument has been designed, constructed, and verified to provide high sensitivity depthresolved birefringence and phase retardation measurements of the retinal nerve fiber layer. Over the past decade, optical coherencedomain techniques such as optical coherencedomain reflectometry ocdr and optical coherence tomography oct have come into their own for use in biological imaging 1,2. Lowcoherence, highresolution optical reflectometry for. Lowcoherence interferometry lci is a noncontact optical sensing technology an optical probe directs a beam of lowcoherence light at a sample surface and sends reflected light signals to an interferometric detector interferometer via an optical fiber for interpretation. Differentiation of ex vivo human breast tissue using polarizationsensitive optical coherence tomography fredrick a. High resolution optical low coherence reflectometry in. Oct 17, 2016 cataract surgery is the most common surgical procedure in ophthalmology.
Cataract surgery is the most common surgical procedure in ophthalmology. Low coherence interferometry and optical coherence. It injects a series of optical pulses into the fiber under test and extracts, from the same end of the fiber, light that is scattered rayleigh backscatter or reflected back from points along the fiber. The otdr launches a series of high speed optical pulses into the fiber to be measured. When, as in the diagram, the measured sample consists of a stack of semitransparent material layers, light.
Capabilities and limitations of coherent optical frequencydomain reflectometry ofdr instrument based on the use of a tunable ber laser with a very narrow linewidth 10 khz tuned mechanically by a piezoelectric transducer makes possible. A 3 db fused coupler was used to couple the low coherence signal to the sensor array and the reflected signals to the autocorrelator. Olcr stands for optical lowcoherence reflectometry. Strong reflections in the measurement range do not affect peaks from weaker reflections. Angleresolved lowcoherence interferometry alci is an emerging when.
These techniques operate on interferometric principles and use heterodyne detection to achieve high detection sensitivity. Milner, polarizationmaintaining fiberbased optical low coherence reflectometer for characterization and ranging of birefringence, opt. Biometry data and accurate intraocular lens iol calculations are very important in achieving the desired refractive outcomes. Metaanalysis of optical lowcoherence reflectometry versus partial.
An optical timedomain reflectometer otdr is an optoelectronic instrument used to characterize an optical fiber. That is because of the vacancy of technologies capable to perform images with. Development and applications 411 organizing this data by areas of knowledge and looking only for the most expressive ones, fig. Robust and rapid optical lowcoherence reflectometer using. Full range polarizationsensitive fourier domain optical.
Determination of birefringence and absolute optic axis. We present a polarizationsensitive optical coherencedomain reflectometer capable of characterizing the phase retardation between orthogonal linear polarization modes at each reflection point in a birefringent sample. Low coherence interferometry lci is a noncontact optical sensing technology an optical probe directs a beam of low coherence light at a sample surface and sends reflected light signals to an interferometric detector interferometer via an optical fiber for interpretation. Axial and peripheral eye length measured with optical low.
Phase noise owing to environmental perturbations that is common to both channels is canceled, resulting in accurate measurement of the phase difference between light backscattered from two spatially separated sites. Sensitivity advantage of swept source and fourier domain optical coherence tomography michael a. The aim of our study was to report the accuracy of olcr biometry obtained from the lenstar ls900 haagstreit ag, koniz, switzerland in predicting post operative refraction in eyes undergoing phacovitrectomy for macular pathology erm or mh. Optical lowcoherence reflectometry how is optical low. Validation of optical low coherence reflectometry retinal and. Olcr is defined as optical lowcoherence reflectometry somewhat frequently. Olcr abbreviation stands for optical lowcoherence reflectometry. Mirrors m 3 and m 4 are mounted on a manual translation stage, which. An optical time domain reflectometer otdr is a precision instrument used to locate events or faults along a fiber link, typically within an optical communications network. The aim of this study was to compare measurements using a new optical low coherence reflectometry olcr biometer oa2000 and the gold standard partial coherence interferometry pci optical biometer iolmaster 500.
Phasesensitive optical lowcoherence reflectometry for. Pdf on sep 22, 1999, cyril lupi and others published optical low coherence reflectometry. Optical low coherence reflectometry olcr is a technique that permits to measure the absolute position and to determine optical properties. Grating with lengths below two millimeters have been fabricated in standard telecommunication fibers. The scan rate and scan range of the reflectometer are measured to be 2. A birefringentfiberbased dualchannel optical low coherence reflectometer capable of differential phase measurement is described. Olcr optical lowcoherence reflectometry acronymfinder. The twoelement scanning system is used to generate rapid signal acquisition in an optical lowcoherence reflectometer. The lowcoherence reflectometer with the proposed optical delay line can perform a rapid scanning imaging and two dimensional. Twentytwo patients hospitalized at our eye clinic undergoing cataract surgery were assigned to. Osa rapid and scalable scans at 21 ms in optical low. Such reflections are often encountered in optical fiberbased communications systems and can cause degraded performance.
The optical low coherence reflectometer olcr is a very powerful tool to characterize optical fibres and integrated optical components. Validation of optical low coherence reflectometry retinal. Comparison of optical lowcoherence reflectometry and. Optical coherence tomography oct is a noninvasive high resolution optical imaging technology based on interference between signal from an object under investigation and a local reference signal. The aim of this study was to compare measurements using a new optical low coherence reflectometry olcr biometer oa2000 and the gold standard partial coherence interferometry pci optical. Domain reflectometry in order to touchenable thin, modu lar, and deformable. Lowcoherence, highresolution optical reflectometry. Engineering structured light from lasers also inside. Optical coherence tomographyprinciples and applications. Introduction optical coherence tomography oct is a noninvasive, noncontact imaging modality that. Goldblumcomparison and evaluation of ocular biometry using a new noncontact optical lowcoherence reflectometer. Angleresolved lowcoherence interferometry wikipedia. Optical low coherence reflectometry olcr is a technique based on interferometry which is design to detect and localize reflectorsl. Meter measures the level of reflected optical power z that is inherent to the.
It is now possible to scan samples with high spatial resolution and constant high speed 2. Sep 18, 2010 the aim of the study was to determine whether the innovative noncontact optical lowcoherence reflectometry method utilized by the lenstar ls 900 agrees sufficiently with applanation ultrasound ascan technique in routine biometric measurement and intraocular lens power calculation to replace it. Highresolution reflectometer aq7410b the aq7410b is a highresolution optical low coherence reflectometer based upon a michelson interferometer. Photoncounting optical coherencedomain reflectometry using. The ior converts the time that the otdr measures to distance and displays. Optical lowcoherence reflectometry for nondestructive process measurements summer lockerbie randall, anatol m. What is the abbreviation for optical lowcoherence reflectometry. Photoncounting optical coherencedomain reflectometry using superconducting singlephoton detectors nishant mohan1, olga minaeva2,3, gregory n. Osa optical lowcoherence reflectometer for differential. Green center for process analytical chemistry university of washington box 351700 seattle, wa 981951700 abstract.
It is used for medical imaging and industrial nondestructive testing ndt. Optical lowcoherence reflectometry how is optical lowcoherence reflectometry abbreviated. Optical lowcoherence reflectometry has been used extensively in ranging of optical components1,2 and more. Robust and rapid optical lowcoherence reflectometer using a.
Optical low coherence reflectometry and the ofdr optical frequency. Meet the newly elected members of the board of governors 20192021 hot topics at the ieee photonics conference ieee photonics society at the national society of black physicists conference. In the 1990s, ultrasound derivation of al and manual keratometry. Analysis of opticalinjected distributed feedback lasers. Optical lowcoherence reflectometer for differential. A commercially available optical lowcoherence reflectometer hp 8504a precision reflectometer performed the autocorrelation function.
The analysis of the attenuation rate of the lowcoherence reflectometer signal depending on the probing depth provides additional information for the identification of skin morphologic changes and the analysis of the effect of immersion agents on the biotissue optical properties. Clemetson ia, tappeiner c, goldblum d 2009 comparison and evaluation of ocular biometry using a new noncontact optical lowcoherence reflectometer. Oct can produce in real time a crosssection image of the object, i. Optical lowcoherence reflectometry enables preoperative detection of zonular weakness in pseudoexfoliation syndrome. The optical delay line possesses the benefits that it is compact, easy to fabricate and can avoid walkoff problem during scanning. It is based on an interferometric method that uses a probe light characterized by a broad spectrum. Birefringence measurement of the retinal nerve fiber layer by. Low cost good for characterization of devices with low to high reflectivity. Optical lowcoherence reflectometry enables preoperative. Pdf a new commercially available optical low coherence reflectometry device lenstar, haagstreit or allegro biograph, wavelight provides. Thickness measurements with a repetitiveness of 384 hz and a longitudinal scanning speed of 21 ms in.
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