Tunable Sources -Optical Coherence Tomography News

Articles in category: Tunable Sources

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1. Resolving absolute depth in circular-ranging optical coherence tomography by using a degenerate frequency comb
  
  Explore OSA | OSA Publishing Jan 12 2020 Tunable Sources
  
  In Fourier-domain optical coherence tomography, an interference signal is generated that spans an RF bandwidth proportional to the product of three parameters: the imaging range, the imaging speed, and the inverse of the axial resolution. Circular-ranging optical coherence tomography (CR-OCT) architectures were introduced to ease long-range imaging by decoupling the imaging range from the signal RF bandwidth. As a consequence, present CR-OCT systems resolve the relative, but not the absolute, depth location of the scatterers. We introduce here a modified implementation of CR-OCT that uses a degenerate frequency comb source that allows recovery of absolute depth information while only minimally ...
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  Mentions: Massachusetts General Hospital Harvard University Benjamin J. Vakoc
2. GaAs-Based InPBi Quantum Dots for High Efficiency Super-Luminescence Diodes
  
  Explore MDPI Open Access Journals Platform Dec 6 2019 Broadband Sources , Tunable Sources
  
  InPBi exhibits broad and strong photoluminescence at room temperature, and is a potential candidate for fabricating super-luminescence diodes applied in optical coherence tomography. In this paper, the strained InPBi quantum dot (QD) embedded in the AlGaAs barrier on a GaAs platform is proposed to enhance the light emission efficiency and further broaden the photoluminescence spectrum. The finite element method is used to calculate the strain distribution, band alignment and confined levels of InPBi QDs. The carrier recombinations between the ground states and the deep levels are systematically investigated. A high Bi content and a flat QD shape are found preferable ...
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3. Multimodality Imaging Approach for Combined Central Retinal Vein and Artery Occlusion: The Role of Optical Coherence Tomography Angiography
  
  Explore Karger Publishers Dec 4 2019 Ophthalmology , Tunable Sources
  
  Combined central retinal artery and vein occlusion is an uncommon vascular pathology that can cause severe and permanent visual impairment. Optical coherence tomography angiography (OCTA) is a newly available, noninvasive imaging technique that can potentially improve understanding of the structural and vascular implications and prognosis of this infrequent pathology. The present report describes the principal clinical findings in a case of combined central retinal artery and vein occlusion, as detected by the different imaging modalities available in a tertiary referral hospital. OCTA wide-field montage images identified an extensive area of nonperfusion on the macula with involvement of the entire retina ...
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4. Surface emitting laser, information obtaining apparatus, and imaging apparatus
  
  Explore uspto.gov Nov 26 2019 Patents , Tunable Sources
  
  The present invention provides a surface emitting laser the wavelength-tunable band of which is wide. The wavelength-tunable surface emitting laser includes a first reflector (101), an active layer (103) disposed on the first reflector (101), a beam portion (110) disposed over the active layer (103) with an air gap therebetween, and a second reflector (120) disposed on the beam portion (110). The second reflector (120) has a distributed Bragg reflector consisting of a stack of dielectric layers. The beam portion (110) has a distributed Bragg reflector consisting of a stack of conductive semiconductor layers.
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  Mentions: Canon Medical Systems
5. Method for signal processing in optical coherence tomography by means of a tunable light source
  
  Explore uspto.gov Nov 26 2019 Patents , Tunable Sources
  
  The invention relates to a method for signal processing in optical coherence tomography by means of a tunable light source (swept source), comprising the following steps: tuning the light source and sensing a signal intensity of the light source in linear dependence on the respective wave number (k) of the tunable light source and producing a signal intensity distribution in dependence on k; applying a window function to the sensed signal intensity distribution and producing a weighted signal intensity distribution; and applying a fast Fourier transform (FFT) to the weighted signal intensity distribution; and characterized in that, in the tuning ...
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  Mentions: Heidelberg Engineering
6. Thorlabs Extends MEMS-VCSEL Swept-Wavelength Laser Source Offering to Include 1060 nm
  
  Explore Optical Coherence Tomography News Nov 8 2019 Other Business News , Tunable Sources
  
  Thorlabs announced today that it has released next-generation versions of its MEMS-VCSEL Swept-Wavelength Laser Sources. The new SL10 series, centered at 1060 nm, complements the already well-established SL13 series at 1300 nm and is available with four different sweep rates ranging from 60 kHz to 400 kHz. Based on a patented microelectromechanical system (MEMS) tunable vertical cavity surface emitting laser (VCSEL), these light sources feature a record-breaking coherence length of over 100 mm and include an active power control that maintains constant output power over the lifetime of the laser. All drive electronics and trigger signals needed to seamlessly integrate ...
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  Mentions: Thorlabs
7. Acousto-optically tuned external-cavity laser diode for optical coherence tomography with continuous wavelet transform
  
  Explore SPIE Digital Library Oct 30 2019 Tunable Sources
  
  We propose an acousto-optically tuned external-cavity laser diode (ECLD) based on the Littrow configuration to expand the wavelength-scanning range and eliminate mechanical motions. The scanning range and tuning rate of our prototype were 68.85 nm and more than 100 kHz, respectively, without any mode hop. Moreover, we implemented this improved ECLD in an optical coherence tomography imaging system and conducted a measurement of the two-dimensional thickness distribution of a thin glass plate via continuous wavelet transform analysis.
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8. Highly-stable, multi-megahertz circular-ranging optical coherence tomography at 1.3 µm based on a chirped fiber Bragg grating
  
  Explore arxiv.org Oct 26 2019 Tunable Sources
  
  In Fourier-domain optical coherence tomography (OCT), the finite bandwidth of the acquisition electronics constrains the depth range and speed of the system. Circular-ranging (CR) OCT methods use optical-domain compression to surpass this limit. However, the CR-OCT system architectures of prior reports were limited by poor stability and were confined to the 1.55 µm wavelength range. In this work, we describe a novel CR-OCT architecture that is free from these limitations. To ensure stable operation, temperature sensitive optical modules within the system were replaced; the kilometer-length fiber spools used in the stretched-pulse mode-locked (SPML) laser was eliminated in favor of ...
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  Mentions: Brett E. Bouma Massachusetts General Hospital Harvard University
9. Marie Curie PhD Studentship: VCSELs for Optical Coherence Tomography
  
  Explore EURAXESS Oct 8 2019 Tunable Sources , Jobs & Studentships
  
  Two Marie Curie Early Stage Researcher/PhD positions for 36 months starting from 1st February and 1st of April 2020, respectively, are available within the Institute for Microwave Engineering and Photonics (Photonics group/ Terahertz Devices and Systems group). These are supported by an EU funded Marie Curie Innovative Training Network, 860807, jointly organised with 14 other universities, companies and hospitals in Europe. Students will spend most of their time in Darmstadt, Germany with secondments to at least one University and one industrial partner each. Research will focus on innovative solutions for swept sources for optical coherence tomography based on widely ...
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10. Wavelength tunable laser device
  
  Explore uspto.gov Sep 24 2019 Patents , Tunable Sources
  
  A photonic integrated circuit wavelength tunable laser device includes a gain element integrated into a photonic integrated circuit. The gain element provides optical gain to an optical signal. A tunable filter is integrated into the photonic integrated circuit. A modulator is integrated into the photonic integrated circuit that modulates the optical signal as a function of time, wherein the gain element, the tunable filter, and the modulator form a wavelength tunable laser device having a wavelength that tunes as a function of time.
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  Mentions: Eric A. Swanson
11. Surface emitting laser, information acquiring apparatus, imaging apparatus, laser array, and method of manufacturing surface emitting laser
  
  Explore uspto.gov Sep 17 2019 Patents , Tunable Sources
  
  A surface emitting laser having a wide wavelength tunable band is provided. A surface emitting laser includes a first reflecting mirror (102); a second reflecting mirror (116); and an active layer (104) arranged between the first reflecting mirror (102) and the second reflecting mirror (116), a gap being formed between the second reflecting mirror (116) and the active layer (104), an oscillation wavelength being tunable. The second reflecting mirror (116) includes a beam (108) comprising a single-crystal semiconductor, and a dielectric multilayer film (110) supported by the beam (108), and the dielectric multilayer film (110) is arranged in an opening ...
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  Mentions: Canon Medical Systems
12. Real time FPGA resampling for swept source optical coherence tomography
  
  Explore uspto.gov Aug 27 2019 Patents , Tunable Sources
  
  Real-time swept source OCT data is most often sampled using a specially cut hardware k-clock. The present invention involves mathematically resampling signals within an FPGA-based data acquisition board based on data sampled from a wide free spectral range reference interferometer. The FPGA can then multiply up the reference clock rate to achieve greater imaging depth. The Nyquist fold-over depth can thus be programmed from a standard reference to an arbitrary depth, much as PLL frequency synthesizer can produce many frequencies from a standard stable reference. The system is also capable of real-time performance.
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  Mentions: Axsun Technologies Brian D. Goldberg Bart Johnson
13. Laser swept source with controlled mode locking for OCT medical imaging
  
  Explore uspto.gov Aug 6 2019 Patents , Tunable Sources
  
  An optical coherence analysis system uses a laser swept source that is constrained to operate in a mode locked condition. This is accomplished by synchronously changing the laser cavity's gain and/or phase based on the round trip travel time of light in the cavity. Many high-speed wavelength swept laser sources emit pulses synchronized with the round trip time of the cavity as part of a nonlinear optical frequency red shifting process. Stable pulsation is associated with smooth tuning and low relative intensity noise. Addition of mode-locking methods to this class of lasers can control and stabilize these lasers ...
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  Mentions: Axsun Technologies Dale Flanders Bart Johnson
14. Praevium Research Inc Receives a 2019 NIH Grant for $497,982 for Manufacturable and Reliable Electrically-Pumped Micro-Electromechanically Tunable VCSELs for Low-Cost Ophthalmic SS-OCT
  
  Explore Optical Coherence Tomography News Jul 23 2019 Funding , Tunable Sources
  
  Praevium Research Inc Receives a 2019 NIH Grant for $497,982 for Manufacturable and Reliable Electrically-Pumped Micro-Electromechanically Tunable Vertical Cavity Surface Emitting Lasers for Low-Cost Ophthalmic Swept Source Optical Coherence Tomography. The principal investigator is Christopher Burgner. The program began in 2012 and ends in 2020. Below is a summary of the proposed work. The ultimate goal of this effort is to bring advanced ophthalmic swept source optical coherence tomography (SS-OCT) imaging to low cost broadly accessible environments. SS-OCT is a powerful non-invasive diagnostic imaging modality, and an increasingly valuable tool in the early detection and monitoring of a number ...
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  Mentions: Praevium Research
15. Convective Nozaki-Bekki holes in a long cavity OCT laser
  
  Explore OSA | OSA Publishing Jun 6 2019 Tunable Sources
  
  We show, both experimentally and theoretically, that the loss of coherence of a long cavity optical coherence tomography (OCT) laser can be described as a transition from laminar to turbulent flows. We demonstrate that in this strongly dissipative system, the transition happens either via an absolute or a convective instability depending on the laser parameters. In the latter case, the transition occurs via formation of localised structures in the laminar regime, which trigger the formation of growing and drifting puffs of turbulence. Experimentally, we demonstrate that these turbulent bursts are seeded by appearance of Nozaki-Bekki holes, characterised by the zero ...
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16. Fourier-domain mode-locked laser combined with a master-oscillator power amplifier architecture
  
  Explore OSA | OSA Publishing Apr 14 2019 Tunable Sources
  
  Originally introduced in 2005 for high-speed optical coherence tomography, the rapidly wavelength-swept Fourier-domain mode-locked (FDML) laser still, to this day, enables highest imaging speeds through a very high-speed spectral tuning capability. The FDML laser achieves a tuning bandwidth of over 1/10th of its center wavelength and can sweep this entire bandwidth in less than a microsecond. Interestingly, even though it covers a very broad spectral range, instantaneously it has a narrow spectral linewidth that puts it in a unique space compared to other high-speed broadband laser sources, e.g., mode-locked lasers or supercontinuum sources. Although it has been applied ...
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  Mentions: Bahram Jalali UCLA
17. Agile imaging system
  
  Explore uspto.gov Feb 26 2019 Patents , Tunable Sources
  
  An agile optical imaging system for optical coherence tomography imaging using a tunable source comprising a wavelength tunable VCL laser is disclosed. The tunable source has long coherence length and is capable of high sweep repetition rate, as well as changing the sweep trajectory, sweep speed, sweep repetition rate, sweep linearity, and emission wavelength range on the fly to support multiple modes of OCT imaging. The imaging system also offers new enhanced dynamic range imaging capability for accommodating bright reflections. Multiscale imaging capability allows measurement over orders of magnitude dimensional scales. The imaging system and methods for generating the waveforms ...
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  Mentions: Thorlabs Alex E. Cable Benjamin M. Potsaid
18. Temperature stabilized phase reference for MEMS based swept sources
  
  Explore SPIE Digital Library Feb 23 2019 Tunable Sources
  
  MEMS tunable lasers are not inherently phase stable because Brownian motion and drive electronics noise make the starting wavelength of the sweep unstable with respect to the electrical sweep trigger. A typical solution to the problem is to use a fiber Bragg reflector wavelength trigger. That is a sub-optimal solution since environmental changes can move both the Bragg peak and the k-clock phase. We have packaged temperature controlled trigger and clock etalons in a butterfly package to solve this environmental problem. By making the wide FSR trigger etalon from silicon and the narrow FSR clock etalon from fused silica, the ...
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  Mentions: Axsun Technologies Bart Johnson
19. Tunable 1060nm VCSEL co-packaged with pump and SOA for OCT and LiDAR
  
  Explore SPIE Digital Library Feb 23 2019 Tunable Sources
  
  A 1060 nm optically pumped tunable VCSEL was formed from an InGaAs/AlGaAs/GaAs half-VCSEL bonded to a MEMS movable mirror on a silicon substrate. The VCSEL was co-packaged in a 14-pin butterfly module with an 825 nm pump laser and a 1060 nm semiconductor optical amplifier. The co-packaged device exhibited shot-noise-limited sensitivity with up to 50 mW output power and 75 nm tunability. Ophthalmic OCT, especially whole-eye imaging and ocular biometry, is considered the primary application of this device. However, we have also investigated LiDAR to greater than 10 meter ranges with non-mechanical beam steering through angular diffraction from ...
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  Mentions: Axsun Technologies Bart Johnson
20. Swept light source and method for controlling the same
  
  Explore uspto.gov Feb 12 2019 Patents , Tunable Sources
  
  Provided is a swept light source including one end surface coupled to a wavelength filter constituted of a diffraction grating and an end mirror via a light deflector and another end surface including a gain medium facing an output coupling mirror and which configures a laser cavity between the end mirror and the output coupling mirror, wherein a drive voltage having an AC voltage on which a DC bias voltage is superimposed is output from a control voltage source of the light deflector to an electrode pair of an electro-optic crystal, light is radiated from a light emitter to the ...
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  Mentions: NTT
21. OptoRes presents world-record 3 MHz swept laser at SPIE BiOS / Photonics West in San Francisco
  
  Explore Optical Coherence Tomography News Jan 31 2019 Other Business News , Tunable Sources
  
  Ideally suited for optical coherence tomography, Optores‘ FDML laser with 3 MHz sweep rate is more than 10x faster than competition. Optores GmbH announces the latest upgrade to its NG-FDML series of wavelength-swept lasers. The SPIE Photonics West conference marks the launch of the new 3 MHz imaging speed option: Double as fast as previously, and more than 10x faster than any other commercially available swept laser. The new device is ideal for optical coherence tomography (OCT) in medicine, biology and industrial inspection. “Multi-MHz sweep rates are necessary for high-resolution 4D-OCT, which shows three-dimensional tissue structure live and in real ...
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  Mentions: James G. Fujimoto Robert A. Huber University of Lübeck
22. Ultrafast Wavenumber Linear-step-swept source Based on Synchronous Lightwave Synthesized Frequency Sweeper
  
  Explore IEEE Xplore Jan 28 2019 Tunable Sources
  
  An ultrafast wavenumber linear-step-swept source based on a synchronous lightwave synthesized frequency sweeper (SLSFS) is demonstrated. A multi-wavelength source is used as a seed source. In SLSFS, the swept range of different wavelength components is precisely controlled by a stable programmable radio frequency (RF) signal applied on a dual-parallel Mach-Zehnder modulator (DP-MZM) instead of a conventional wavelength filter. The identical frequency shifting step of all the wavelength components promises high linear sweeping in frequency domain. The key significance of this technique is that the swept rate and the swept range increases as the number of the seed wavelengths increases. Experimentally ...
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  Mentions: Tianjin University Nankai University
23. Laser-Based Swept Light Source Octlight ApS
  
  Explore Octlight Jan 22 2019 Tunable Sources
  
  CT Swept Source product Caliper targeting biometry in connection with cataract surgery OCTLIGHT ApS announces that it will release its first product Caliper at the SPIE Photonics West 2019 Exhibition at the Moscone Center in San Francisco, US, February 5 th . Caliper is an OCT swept source with application in 3D measurements of the eye geometry – so-called biometry – which finds its use in the treatment of cataract. OEM samples will be available 2019 to meet demand for VCSEL based OCT Swept Source The release of the Caliper product follows years of testing prototypes with potential customers within Ophthalmology. OCTLIGHT is ...
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  Mentions: OCTLIGHT
24. Extended Coherence Length and Depth Ranging Using a Fourier-Domain Mode-Locked Frequency Comb and Circular Interferometric Ranging
  
  Explore journals.aps.org Jan 10 2019 Tunable Sources
  
  Fourier-domain mode locking has been a popular laser design for high-speed optical-frequency-domain imaging (OFDI), but achieving long coherence lengths, and therefore imaging range, has been challenging. The narrow linewidth of a Fourier-domain mode-locked (FDML) frequency-comb (FC) laser could provide an attractive platform for high-speed as well as long-range OFDI. Unfortunately, aliasing artifacts arising from signals beyond the principal measurement depth of the free spectral range have prohibited the use of an FDML FC laser for imaging so far. To make the increased coherence length of an FDML FC laser available, methods to manage such artifacts are required. Recently, coherent circular ...
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  Mentions: Brett E. Bouma Massachusetts Institute of Technology Massachusetts General Hospital
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