Tunable Sources -Optical Coherence Tomography News

Articles in category: Tunable Sources

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1. Unfolding displacement measurement method for the aliasing interferometer signal of a wavelength-comb-swept laser
  
  Explore OSA | OSA Publishing Mar 5 2018 Tunable Sources
  
  We demonstrate an unfolding displacement measurement method to overcome the aliasing problem of wavelength-comb-swept laser (WCSL). Compared to the conventional wavelength-swept laser (WSL), the WCSL exhibits an extended coherence length, owing to the narrowing spectral linewidth of the etalon filter. However, the aliasing interference signal induces an unexpected back-bounced phenomenon during displacement measurement because of the discretely distributed comb-like periodic spectra of the etalon filter. By using the dual-reference interferometry method, the back-bounced displacement measurement can be successfully unfolded to extend the measurement range by two times. In addition, we demonstrate a longer-range surface profiling image over 18 mm within ...
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  Mentions: Chang-Seok Kim Pusan National University Samsung
2. Widely tunable short cavity laser
  
  Explore uspto.gov Dec 12 2017 Patents , Tunable Sources
  
  A tunable source includes a short-cavity laser optimized for performance and reliability in SSOCT imaging systems, spectroscopic detection systems, and other types of detection and sensing systems. The short cavity laser has a large free spectral range cavity, fast tuning response and single transverse, longitudinal and polarization mode operation, and includes embodiments for fast and wide tuning, and optimized spectral shaping. Disclosed are both electrical and optical pumping in a MEMS-VCSEL geometry with mirror and gain regions optimized for wide tuning, high output power, and a variety of preferred wavelength ranges; and a semiconductor optical amplifier, combined with the short-cavity ...
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  Mentions: Thorlabs Alex E. Cable Benjamin M. Potsaid
3. High-resolution retinal swept source optical coherence tomography with an ultra-wideband Fourier-domain mode-locked laser at MHz A-scan rates
  
  Explore OSA | OSA Publishing Dec 9 2017 Ophthalmology , Tunable Sources
  
  We present a new 1060 nm Fourier domain mode locked laser (FDML laser) with a record 143 nm sweep bandwidth at 2∙ 417 kHz = 834 kHz and 120 nm at 1.67 MHz, respectively. We show that not only the bandwidth alone, but also the shape of the spectrum is critical for the resulting axial resolution, because of the specific wavelength-dependent absorption of the vitreous. The theoretical limit of our setup lies at 5.9 µm axial resolution. In vivo MHz-OCT imaging of human retina is performed and the image quality is compared to the previous results acquired with 70 ...
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  Mentions: Robert A. Huber University of Lübeck Tom Pfeiffer
4. Direct experimental measurement of single-mode and mode-hopping dynamics in frequency swept lasers
  
  Explore OSA | OSA Publishing Oct 30 2017 Tunable Sources
  
  A time-resolved study is presented of the single-mode and mode-switching dynamics observed in swept source vertical cavity surfing emitting lasers and swept wavelength short external cavity lasers. A self-delayed interferometric technique is used to experimentally measure the phase and intensity of these frequency swept lasers, allowing direct examination of the modal dynamics. Visualisation of the instantaneous optical spectrum reveals mode-hop free single mode lasing in the case of the vertical cavity laser, with a tuning rate of 6.3 GHz/ns. More complex mode-switching behaviour occurs in the external cavity laser, with the mode-hopping dynamics found to be dominated by ...
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  Mentions: University College Cork Bryan Kelleher
5. Swept source OCT system and method with phase-locked detection
  
  Explore uspto.gov Oct 10 2017 Patents , Tunable Sources
  
  A swept source OCT system and related method are disclosed. The system comprises a control device for operating a tunable light source in response to an electronic sweep control signal such that the tunable light source carries out wave length sweeps with a repetition rate f.sub.sweep, which depends on the frequency of the sweep control signal. The system further comprises a detection device for the time-resolved detection of an interference signal from a sample beam and a reference beam with the help of a detection cycle signal. The sweep control signal and the detection cycle signal are phase-locked ...
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  Mentions: Robert A. Huber Wolfgang Wieser Thomas Klein
6. Widely tunable swept source
  
  Explore uspto.gov Sep 26 2017 Patents , Tunable Sources
  
  A high-speed, single-mode, high power, reliable and manufacturable wavelength-tunable light source operative to emit wavelength tunable radiation over a wavelength range contained in a wavelength span between about 950 nm and about 1150 nm, including a vertical cavity laser (VCL), the VCL having a gain region with at least one compressively strained quantum well containing Indium, Gallium, and Arsenic.
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  Mentions: Thorlabs Alex E. Cable Praevium Research
7. Eckhaus Instability in the Fourier-Domain Mode Locked Fiber Laser Cavity
  
  Explore arxiv.org Aug 17 2017 Tunable Sources
  
  High frequency fluctuation in the optical signal generated in Fourier-Domain Mode Locked fiber laser (FDML-FL), which is the major problem and degrades the laser performance, is not yet fully analyzed or studied. The basic theory which is causing this high frequency fluctuation is required to clearly understand its dynamics and to control it for various applications. In this letter, by analyzing the signal and system dynamics of FDML-FL, we theoretically demonstrate that the high frequency fluctuation is induced by the intrinsic instability of frequency offset of the signal in cavity with nonlinear gain and spectral filter. Unlike the instabilities observed ...
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  Mentions: University of Washington University of Aberdeen Hong Kong Polytechnic University
8. Highly phase-stable 200 kHz swept-source optical coherence tomography based on KTN electro-optic deflector
  
  Explore OSA | OSA Publishing Jul 18 2017 Tunable Sources
  
  The rapid advance in swept-source optical coherence tomography (SS-OCT) technology has enabled exciting new applications in elastography, angiography, and vibrometry, where both high temporal resolution and phase stability are highly sought-after. In this paper, we present a 200 kHz SS-OCT system centered at 1321 nm by using an electro-optically tuned swept source. The proposed system’s performance was fully characterized, and it possesses superior phase stability (0.0012% scanning variability and <1 ns timing jitter) that is promising for many phase-sensitive imaging applications. Biological experiments were demonstrated within ex vivo human tracheobronchial ciliated epithelium where both the ciliary motion and ...
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  Mentions: Columbia University Christine Hendon
9. Downhole sensing via swept source lasers
  
  Explore uspto.gov Jul 11 2017 Other Non-Medical , Patents , Tunable Sources
  
  Systems and methods for performing downhole analysis within a well bore employ a swept source laser that can be sent downhole to generate high resolution images of the well bore. Various embodiments can also determine other physical properties of a below ground structure. The swept source lasers can create images using low-coherence interferometry or optical coherence tomography. Systems and methods may also be used to determine fluid flow rates towards the sensor at discrete points, such as individual perforations, by measuring the Doppler effect on the light back-scattered from the fluid. Fluid flow information could also be extracted by measuring ...
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10. Broadband wavelength-swept light source system and apparatus employing the same
  
  Explore uspto.gov Jul 11 2017 Patents , Tunable Sources
  
  A light source system includes: a plurality of gain mediums configured to output a corresponding plurality of lights having different center wavelengths from each other; a first light source part configured to connect the plurality of gain mediums to each other in parallel and emit the plurality of lights; a wavelength-swept filter unit configured to sweep wavelengths of the plurality of lights output by the plurality of gain mediums and compensate for spectroscopic optical paths of the plurality of lights; a second light source part configured to connect the first light source part to the wavelength-swept filter unit in series ...
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  Mentions: Samsung
11. Tunable laser array system
  
  Explore uspto.gov Jul 4 2017 Patents , Tunable Sources
  
  A system for swept source optical coherence tomography, the system including a light source emitting multiplexed wavelength-swept radiation over a total wavelength range, the light source including N wavelength-swept vertical cavity lasers (VCL) emitting N tunable VCL outputs having N wavelength trajectories, a combiner for combining the N tunable VCL optical outputs into a common optical path to create the multiplexed wavelength-swept radiation, a splitter for splitting the multiplexed wavelength-swept radiation to a sample and a reference path, an optical detector for detecting an interference signal created by an optical interference between a reflection from the sample and light traversing ...
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  Mentions: Thorlabs Alex E. Cable Benjamin M. Potsaid
12. 16 MHz wavelength-swept and wavelength-stepped laser architectures based on stretched-pulse active mode locking with a single continuously chirped fiber Bragg grating
  
  Explore OSA | OSA Publishing Jun 26 2017 Tunable Sources
  
  We demonstrate a novel high-speed and broadband laser architecture based on stretched pulse active mode locking that provides a wavelength-swept and wavelength-stepped output. The laser utilizes a single intracavity 8.3 meter chirped fiber Bragg grating to generate positive and negative dispersion, and can be operated with or without an intracavity fixed Fabry–Perot etalon to generate wavelength-swept and wavelength-stepped (frequency comb) outputs, respectively. Using a four-path delay line at the output, we achieved 16.3 MHz repetition rates and a 62 nm lasing bandwidth centered at 1550 nm. Single-sided double-pass coherence lengths of 1.25 mm for the wavelength-swept ...
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  Mentions: Massachusetts Institute of Technology Massachusetts General Hospital Harvard University
13. System, apparatus and method for utilizing optical dispersion for fourier-domain optical coherence tomography
  
  Explore uspto.gov Jun 6 2017 Patents , Tunable Sources
  
  An apparatus can be provided which can include a laser arrangement which can be configured to provide a laser radiation, and can include an optical cavity. The optical cavity can include a dispersive optical first arrangement which can be configured to receive and disperse at least one first electro-magnetic radiation so as to provide at least one second electro-magnetic radiation. Such cavity can also include an active optical modulator second arrangement which can be configured to receive and modulate the at least one second radiation so as to provide at least one third electro-magnetic radiation. The optical cavity can further ...
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  Mentions: Massachusetts General Hospital Harvard University Benjamin J. Vakoc
14. Extended bandwidth wavelength swept laser source for high resolution optical frequency domain imaging
  
  Explore OSA | OSA Publishing Apr 4 2017 Tunable Sources
  
  Improving the axial resolution by providing wider bandwidth wavelength swept lasers remains an important issue for optical frequency domain imaging (OFDI). Here, we demonstrate a wide tuning range, all-fiber wavelength swept laser at a center wavelength of 1250 nm by combining two ring cavities that share a single Fabry-Perot tunable filter. The two cavities contain semiconductor optical amplifiers with central wavelengths of 1190 nm and 1292 nm, respectively. To avoid disturbing interference effects in the overlapping spectral region, we modulated the amplifiers in order to obtain consecutive wavelength sweeps in the two spectral regions. The two sweeps were fused together ...
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  Mentions: Brett E. Bouma Massachusetts General Hospital Harvard University
15. Phase-noise analysis of swept-source optical coherence tomography systems
  
  Explore OSA | OSA Publishing Mar 23 2017 Tunable Sources
  
  We propose a new model to characterize the phase noise in swept-source optical coherence tomography (SS-OCT). The new model explicitly incorporates scanning variability, timing jitter, and sample location in addition to intensity noise (shot noise). The model was analyzed and validated by using both Monte Carlo methods and experiments. We suggest that the proposed model can be used as a guideline for future SS-OCT experimental designs.
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  Mentions: Columbia University Christine Hendon
16. Analysis of polygonal scanning heads: from industrial to high-end applications in swept sources for OCT
  
  Explore Conference Proceedings Mar 18 2017 Tunable Sources
  
  An analysis of polygonal mirror (PM) scanning heads has been performed, in order to provide a tool for their optimal design. The theory developed brings under the same umbrella applications that range from industrial dimensional measurements to high-end biomedical imaging, for example for broadband laser sources swept in frequency for Swept Source Optical Coherence Tomography (SS-OCT). The different characteristic parameters of the PM scanning heads were considered in order to achieve a rigorous analysis: number of PM facets, inner radius of the PM, eccentricity of the PM pivot with regard to the incident fixed laser beam, distance from this beam ...
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  Mentions: Virgil-Florin Duma
17. Wavelength tunable laser device and optical coherence tomography apparatus
  
  Explore uspto.gov Mar 14 2017 Patents , Tunable Sources
  
  A wavelength tunable laser device, including: a first reflector; a second reflector; an active layer formed between the first reflector and the second reflector; a quantum well structure layer that exhibits a quantum confined stark effect; and an electrode configured to apply a reverse bias voltage to the quantum well structure layer, wherein the active layer and the second reflector have a gap formed therebetween, the gap having a length to be changed to thereby sweep a resonance wavelength, and wherein the electrode is further configured to change application of the reverse bias voltage to be applied to the quantum ...
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  Mentions: Canon Medical Systems
18. A linearly frequency-swept high-speed-rate multi-wavelength laser for optical coherence tomography
  
  Explore Conference Proceedings Mar 1 2017 Tunable Sources
  
  We proposed and demonstrated a linearly frequency-swept multi-wavelength laser source for optical coherence tomography (OCT) eliminating the need of wavenumber space resampling in the postprocessing progress. The source consists of a multi-wavelength fiber laser source (MFS) and an optical sweeping loop. In this novel laser source, an equally spaced multi-wavelength laser is swept simultaneously by a certain step each time in the frequency domain in the optical sweeping loop. The sweeping step is determined by radio frequency (RF) signal which can be precisely controlled. Thus the sweeping behavior strictly maintains a linear relationship between time and frequency. We experimentally achieved ...
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  Mentions: Tianjin University
19. Stable wavelength-swept light source designed for industrial applications using KTN beam-scanning technology
  
  Explore Conference Proceedings Mar 1 2017 Tunable Sources
  
  Using light-beam scanning technology based on a potassium tantalate niobate (KTa 1-x Nb x O 3 , KTN) single crystal, we constructed a wavelength-swept light source for industrial applications. The KTN crystal is placed in an external cavity as an electro-optic deflector for wavelength scanning without any mechanical operation. Cavity arrangement and mechanism elements are specially designed for long-term stability and environmental robustness. In addition, we updated the handling of the KTN crystal. We used a pair of thermistors for accurate temperature monitoring, and weakly irradiated the crystal with a 405-nm light during operation to achieve drift suppression. We selected a ...
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  Mentions: Hamamatsu Photonics NTT
20. Analysis of FDML lasers with meter range coherence
  
  Explore Conference Proceedings Mar 1 2017 Tunable Sources
  
  FDML lasers provide sweep rates in the MHz range at wide optical bandwidths, making them ideal sources for high speed OCT. Recently, at lower speed, ultralong-range swept-source OCT has been demonstrated using a tunable vertical cavity surface emitting laser (VCSEL) and also using a Vernier-tunable laser. These sources provide relatively high sweep rates and meter range coherence lengths. In order to achieve similar coherence, we developed an extremely well dispersion compensated Fourier Domain Mode Locked (FDML) laser, running at 3.2 MHz sweep rate and 120 nm spectral bandwidth. We demonstrate that this laser offers meter range coherence and enables ...
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  Mentions: Robert A. Huber Wolfgang Wieser University of Lübeck
21. High frame-rate en face optical coherence tomography system using KTN optical beam deflector
  
  Explore Conference Proceedings Feb 23 2017 Tunable Sources
  
  We developed high frame-rate en face optical coherence tomography (OCT) system using KTa 1-x Nb x O 3 (KTN) optical beam deflector. In the imaging system, the fast scanning was performed at 200 kHz by the KTN optical beam deflector, while the slow scanning was performed at 800 Hz by the galvanometer mirror. As a preliminary experiment, we succeeded in obtaining en face OCT images of human fingerprint with a frame rate of 800 fps. This is the highest frame-rate obtained using time-domain (TD) en face OCT imaging. The 3D-OCT image of sweat gland was also obtained by our imaging ...
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  Mentions: NTT Osaka University
22. Dependence on fiber Fabry-Pérot tunable filter characteristics in an all-fiber swept-wavelength laser for use in an optical coherence tomography system
  
  Explore Conference Proceedings Feb 23 2017 Tunable Sources
  
  Optical coherence tomography (OCT) has become a useful and common diagnostic tool within the field of ophthalmology. Although presently a commercial technology, research continues in improving image quality and applying the imaging method to other tissue types. Swept-wavelength lasers based upon fiber ring cavities containing fiber Fabry-P´erot tunable filters (FFP-TF), as an intracavity element, provide swept-source optical coherence tomography (SS-OCT) systems with a robust and scalable platform. The FFP-TF can be fabricated within a large range of operating wavelengths, free spectral ranges (FSR), and finesses. To date, FFP-TFs have been fabricated at operating wavelengths from 400 nm to 2 ...
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  Mentions: Micron Optics
23. Integrated dual swept source alternating same scan band for OCT medical imaging
  
  Explore uspto.gov Feb 21 2017 Patents , Tunable Sources
  
  An optical coherence analysis system comprising: a first swept source that generates a first optical signal that is tuned over a first spectral scan band, a second swept source that generates a second optical signal that is tuned over a second spectral scan band, a combiner for combining the first optical signal and the second optical signal to form a combined optical signal, an interferometer for dividing the combined optical signal between a reference arm leading to a reference reflector and a sample arm leading to a sample, and a detector system for detecting an interference signal generated from the ...
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  Mentions: Axsun Technologies Dale Flanders Bart Johnson
24. Frequency shifting optical swept lightsource system and apparatus to which the system is applied
  
  Explore uspto.gov Feb 21 2017 Tunable Sources
  
  Provided is a frequency shifting optical swept light source system. The system includes a light source that emits light; an amplifier that amplifies the light output from the light source; an optical converter that shifts a frequency of the amplified light and compresses a spectrum of the amplified light; and a controller that controls a current signal applied to the light source such that a repetition rate of the light output from the light source is adjusted, so that an intensity of the amplified light is adjusted, to thereby adjust a position of the compressed spectrum with respect to a ...
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  Mentions: Yoonchan Jeong Samsung
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