1. Articles in category: Tunable Sources

    1-24 of 390 1 2 3 4 ... 15 16 17 »
    1. Laser swept source with controlled mode locking for OCT medical imaging

      Laser swept source with controlled mode locking for OCT medical imaging

      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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    2. 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

      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

      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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    3. Convective Nozaki-Bekki holes in a long cavity OCT laser

      Convective Nozaki-Bekki holes in a long cavity OCT laser

      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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    4. Fourier-domain mode-locked laser combined with a master-oscillator power amplifier architecture

      Fourier-domain mode-locked laser combined with a master-oscillator power amplifier architecture

      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
    5. Agile imaging system

      Agile imaging system

      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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    6. Temperature stabilized phase reference for MEMS based swept sources

      Temperature stabilized phase reference for MEMS based swept 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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    7. Tunable 1060nm VCSEL co-packaged with pump and SOA for OCT and LiDAR

      Tunable 1060nm VCSEL co-packaged with pump and SOA for OCT and LiDAR

      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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    8. Swept light source and method for controlling the same

      Swept light source and method for controlling the same

      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
    9. OptoRes presents world-record 3 MHz swept laser at SPIE BiOS / Photonics West in San Francisco

      OptoRes presents world-record 3 MHz swept laser at SPIE BiOS / Photonics West in San Francisco

      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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    10. Ultrafast Wavenumber Linear-step-swept source Based on Synchronous Lightwave Synthesized Frequency Sweeper

      Ultrafast Wavenumber Linear-step-swept source Based on Synchronous Lightwave Synthesized Frequency Sweeper

      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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    11. Laser-Based Swept Light Source Octlight ApS

      Laser-Based Swept Light Source Octlight ApS

      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
    12. Extended Coherence Length and Depth Ranging Using a Fourier-Domain Mode-Locked Frequency Comb and Circular Interferometric Ranging

      Extended Coherence Length and Depth Ranging Using a Fourier-Domain Mode-Locked Frequency Comb and Circular Interferometric Ranging

      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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    13. Santec Announce a Record Wavelength Scan for an Electrically Pumped VCSEL

      Santec Announce a Record Wavelength Scan for an Electrically Pumped VCSEL

      Santec Corporation (JASDAQ: 6777) Santec, a leading manufacturer of tunable lasers, optical instruments, and fiber-optic components, announces a record 88nm wide continuous wavelength scan for an electrically pumped VCSEL (Vertical Cavity Surface Emitting Laser) light source. This performance record for a 1050nm centered VCSEL is a result of a collaborative effort between Santec, Tokyo Institute of Technology and Tokyo University’s Institute of Industrial Science. This result will be reported at the upcoming Photonics West 2019 meeting in San Francisco [1]. The High-speed Scanning Tunable VCSEL’s element is made up of two parts; the VCSEL, responsible for laser oscillation ...

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    14. Thorlabs Extends VEGA Swept Source OCT Offering

      Thorlabs Extends VEGA Swept Source OCT Offering

      Thorlabs announced today that it has added to its well‐established VEGA™ OCT line by releasing complete imaging systems, VEG210C1 and VEG220C1. Based on Thorlabs’ MEMS‐VCSEL swept‐wavelength laser source technology, these new systems are available in both 100 kHz (VEG210) and 200 kHz (VEG220) variants. Both offer the same low roll‐off and high sensitivity performance found in previous members of the VEGA OCT family. The MEMS‐VCSEL swept source and the imaging module are both packaged into a single housing including the scanning electronics and an interferometer with a balanced detector. Several key hardware controls can be ...

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    15. Dual laser frequency sweep interferometry system and method

      Dual laser frequency sweep interferometry system and method

      An optical arrangement, method and measurement system are disclosed. The arrangement includes a first input to receive a first beam from a frequency swept laser, a second input to receive a second beam from a fixed frequency pump laser source. A non-linear optical artifact receives and intermodulates the first and second beams to generate a third beam, the third being an inverted copy of the first beam mirrored relative to the fixed frequency of the pump laser source. A selective combining element outputs the first and third beams. The non-linear artifact or one or both of the lasers is selected ...

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    16. OCT swept laser with cavity length compensation

      OCT swept laser with cavity length compensation

      An optical coherence tomography system utilizes an optical swept laser that has cavity length compensator that changes an optical length of the laser cavity for different optical frequencies to increase the length of the laser cavity for lower optical frequencies. Specifically, a spectral separation between longitudinal cavity modes of the laser cavity is shortened or alternatively lengthened as a passband of a cavity tuning element sweeps through a scanband of the swept optical signal. In some examples, the compensator is implemented as two gratings. In others, it is implemented as a chirped grating device.

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    17. Long-to-short wavelength swept source

      Long-to-short wavelength swept source

      Most swept external cavity diode lasers tune in the short-to-long wavelength direction (red tuning). Lower relative intensity noise (RIN) and higher output power are typically possible in this direction. We show here that long-to-short tuning (blue tuning) is possible for a short, linear cavity laser that has both low noise and high power. This mode of operation is made possible by nonlinear frequency broadening in the semiconductor optical amplifier (SOA) followed by clipping of the red portion of the spectrum by the micro-electro-mechanical systems (MEMS) tunable Fabry-Perot filter. Blue shifting during gain recovery is an important broadening mechanism. There is ...

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    18. Voltage Noise and Jitter Analysis for Swept Source Optical Coherence Tomography using KTa1-xNbxO3 Deflector

      Voltage Noise and Jitter Analysis for Swept Source Optical Coherence Tomography using KTa1-xNbxO3 Deflector

      This paper describes voltage noise and jitter analysis for the depth deviation of a point spread function in a swept source optical coherence tomography system using a KTa1-xNbxO3 deflector. An interference waveform with voltage noise and jitter was simulated according to a previous report. Typical values for the voltage noise ΔVTYP and jitter ΔtTYPwere also obtained from a previous report and experiment. It was determined that the depth deviation is limited by the ΔtTYP of the system. Therefore, the quality of the tomographic image can be efficiently improved by reducing jitter.

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      Mentions: NTT
    19. SS-OCT enables increased speed, deeper penetration, but steeper cost

      SS-OCT enables increased speed, deeper penetration, but steeper cost

      Swept source OCT has many benefits over spectral domain OCT, but its biggest obstacle today is cost, according to Jay S. Du k er at the American Academy of Optometry annual meeting. SS-OCT is a form of fourier domain detection, which is how the echo time delay is calculated in the device, he said. The SS light source is a tunable laser that rapidly changes the wavelength, which is very expensive, he added. The reflections of depth are detected with photodetectors, not with a camera as with SD-OCT. The longer wavelength of SS-OCT images (1,000 nm to 1,300 ...

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    20. Spectrally tunable illumination system based on acousto-optic diffraction of light

      Spectrally tunable illumination system based on acousto-optic diffraction of light

      Spectrally tunable illumination is widely used for spectral imaging, spectroscopy, spectral-domain optical coherence tomography and other applications. Most of swept-wavelength light sources are based on mechanical change of narrow-band filters or on a supercontinuum laser coupled with a tunable filter. Such commercially available sources suffer either from a limited number of spectral channels or from a spatial noise caused by parasitic interferences. Here, we describe an alternative solution, which is free from the mentioned disadvantages and provides speckle-free uniform illumination. It is based on acousto-optic (AO) diffraction of a wide-band light. AO tunable filters (AOTFs) are fully software-controlled solid-state devices ...

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    21. Extended coherence length and depth ranging using a Fourier domain mode-locked frequency comb and circular interferometric ranging

      Extended coherence length and depth ranging using a Fourier domain mode-locked frequency comb and circular interferometric ranging

      Fourier domain mode-locking (FDML) 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 instantaneous linewidth of a frequency comb (FC) FDML laser could provide an attractive platform for high speed as well as long range OFDI. Unfortunately, aliasing artifacts arising from signals beyond the principle measurement depth of the free spectral range have prohibited the use of a FC FDML for imaging so far. To make the enhanced coherence length of FC FDML laser available, methods to manage such artifacts are ...

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    22. OCT system with bonded MEMS tunable mirror VCSEL swept source

      OCT system with bonded MEMS tunable mirror VCSEL swept source

      A microelectromechanical systems (MEMS)-tunable vertical-cavity surface-emitting laser (VCSEL) in which the MEMS mirror is bonded to the active region. This allows for a separate electrostatic cavity that is outside the laser's optical resonant cavity. Moreover, the use of this cavity configuration allows the MEMS mirror to be tuned by pulling the mirror away from the active region. This reduces the risk of snap down. Moreover, since the MEMS mirror is now bonded to the active region, much wider latitude is available in the technologies that are used to fabricate the MEMS mirror. This is preferably deployed as a ...

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    23. Thorlabs Releases New MEMS‐VCSEL Swept‐Wavelength Laser Sources

      Thorlabs Releases New MEMS‐VCSEL Swept‐Wavelength Laser Sources

      Thorlabs announced today that it has released next‐generation versions of its 1300 nm MEMS‐VCSEL Swept‐Wavelength Laser Sources. With a record‐breaking coherence length of over 100 mm and sweep rates of either 100 kHz or 200 kHz, the SL131090 and SL132120 are the only commercially available MEMS‐VCSEL laser sources on the market. Based on a patented microelectromechanical system (MEMS) tunable vertical cavity surface emitting laser (VCSEL), these light sources 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 these ...

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      Mentions: Thorlabs
    24. Ultra low noise Fourier domain mode locked laser for high quality megahertz optical coherence tomography

      Ultra low noise Fourier domain mode locked laser for high quality megahertz optical coherence tomography

      We investigate the origin of high frequency noise in Fourier domain mode locked (FDML) lasers and present an extremely well dispersion compensated setup which virtually eliminates intensity noise and dramatically improves coherence properties. We show optical coherence tomography (OCT) imaging at 3.2 MHz A-scan rate and demonstrate the positive impact of the described improvements on the image quality. Especially in highly scattering samples, at specular reflections and for strong signals at large depth, the noise in optical coherence tomography images is significantly reduced. We also describe a simple model that suggests a passive physical stabilizing mechanism that leads to ...

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    1-24 of 390 1 2 3 4 ... 15 16 17 »
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