1. Articles in category: Broadband Sources

    1-24 of 307 1 2 3 4 ... 11 12 13 »
    1. Low pump power coherent supercontinuum generation in heavy metal oxide solid-core photonic crystal fibers infiltrated with carbon tetrachloride covering 930–2500 nm

      Low pump power coherent supercontinuum generation in heavy metal oxide solid-core photonic crystal fibers infiltrated with carbon tetrachloride covering 930–2500 nm

      All-normal dispersion supercontinuum (ANDi SC) generation in a lead-bismuth-gallate glass solid-core photonic crystal fiber (PCF) with cladding air-holes infiltrated with carbon tetrachloride (CCl 4 ) is experimentally investigated and numerically verified. The liquid infiltration results in additional degrees of freedom that are complimentary to conventional dispersion engineering techniques and that allow the design of soft-glass ANDi fibers with an exceptionally flat near-zero dispersion profile. The unique combination of high nonlinearity and low normal dispersion enables the generation of a coherent, low-noise SC covering 0.93–2.5 µm requiring only 12.5 kW of pump peak power delivered by a standard ...

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      Mentions: Thorlabs
    2. Flattening the curve: Nano-film enhanced supercontinuum edition

      Flattening the curve: Nano-film enhanced supercontinuum edition

      Providing light with tailored properties through ultrafast supercontinuum generation represents an active field of nonlinear science research. A German-Australian research collaboration has presented a new concept that includes a longitudinally varying thickness nano-films in microstructured exposed core fibers. This offers low input energy, broadband and spectrally flattened spectra in the near infrared with high pulse-to-pulse stability, establishing a novel class of light sources for fields such as biophotonics, medical diagnostics, environmental sciences, or metrology.

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    3. Millimeter-scale chip-based supercontinuum generation

      Millimeter-scale chip-based supercontinuum generation

      In optics, when a collection of nonlinear processes act together on a pump beam, the resulting spectral broadening of the original pump beam gives rise to a supercontinuum . Supercontinuum sources for optical coherence tomography are of great interest since they provide a broad bandwidth for high resolution and high-power imaging sensitivity. For commercial fiber-based supercontinuum systems, researchers use high pump powers to generate a broad bandwidth and customized optical filters to modulate the spectra. In a new report now published on Science Advances , Xingchen Ji and a research team in electrical engineering, biomedical engineering and applied physics at the Columbia ...

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    4. Millimeter-scale chip–based supercontinuum generation for optical coherence tomography

      Millimeter-scale chip–based supercontinuum generation for optical coherence tomography

      Supercontinuum sources for optical coherence tomography (OCT) have raised great interest as they provide broad bandwidth to enable high resolution and high power to improve imaging sensitivity. Commercial fiber-based supercontinuum systems require high pump powers to generate broad bandwidth and customized optical filters to shape/attenuate the spectra. They also have limited sensitivity and depth performance. We introduce a supercontinuum platform based on a 1-mm 2 Si 3 N 4 photonic chip for OCT. We directly pump and efficiently generate supercontinuum near 1300 nm without any postfiltering. With a 25-pJ pump pulse, we generate a broadband spectrum with a flat ...

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    5. Microresonator-frequency-comb-based platform for clinical high-resolution optical coherence tomography

      Microresonator-frequency-comb-based platform for clinical high-resolution optical coherence tomography

      A method of providing optical coherence tomography (OCT) imaging may comprise using an on-chip frequency comb source interfaced with an OCT system by a circulator as an imaging source and reconstructing OCT images from resulting spectral data from target tissue illuminated by the imaging source.

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    6. White Paper on Superluminscent Diodes by Anritsu

      White Paper on Superluminscent Diodes  by Anritsu

      Sensing systems using optical fibers as well as spectroscopic techniques using light absorption in the near-infrared domain of organic molecules are making remarkable advances and the need for light sources for even higher-performance sensing is accelerating. In these circumstances, the Super Luminescent Diode (SLD) is being adopted as a light source for optical-fiber sensing applications due to its broad optical spectrum with an output power matching LDs and low coherence, while featuring excellent optical fiber coupling efficiency.

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    7. Shot-noise limited, supercontinuum-based optical coherence tomography

      Shot-noise limited, supercontinuum-based optical coherence tomography

      We present the first demonstration of shot-noise limited supercontinuum-based spectral domain optical coherence tomography (SD-OCT) with an axial resolution of 5.9 μm at a center wavelength of 1370 nm. Current supercontinuum-based SD-OCT systems cannot be operated in the shot-noise limited detection regime because of severe pulse-to-pulse relative intensity noise of the supercontinuum source. To overcome this disadvantage, we have developed a low-noise supercontinuum source based on an all-normal dispersion (ANDi) fiber, pumped by a femtosecond laser. The noise performance of our 90 MHz ANDi fiber-based supercontinuum source is compared to that of two commercial sources operating at 80 and ...

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    8. Optical coherence hyperspectral microscopy with a single supercontinuum light source

      Optical coherence hyperspectral microscopy with a single supercontinuum light source

      In the paper, we have developed an optical coherence hyperspectral microscopy with a single supercontinuum light source. The microscopy consists of optical coherence tomography (OCT) and hyperspectral imaging (HSI), which can visualize the structural and functional characteristics of biological tissues. The 500-700 nm band is selected for HSI and OCT imaging, where HSI enables imaging of oxygen saturation and hemoglobin (Hb) content, while OCT acquires structural characteristics to assess the morphology of biological tissues. The system performance of the optical coherence hyperspectral microscopy is verified by normal mice ears, and the practical applications of the microscopy is further performed in ...

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    9. Soliton microcomb based spectral domain optical coherence tomography

      Soliton microcomb based spectral domain optical coherence tomography

      Spectral domain optical coherence tomography (OCT) is a widely employed, minimally invasive bio-medical imaging technique, which requires a broadband light source, typically implemented by super-luminescent diodes. Recent advances in soliton based photonic integrated frequency combs (soliton microcombs) have enabled the development of low-noise, broadband chipscale frequency comb sources, whose potential for OCT imaging has not yet been unexplored. Here, we explore the use of dissipative Kerr soliton microcombs in spectral domain OCT and show that, by using photonic chipscale Si 3 N 4 resonators in conjunction with 1300 nm pump lasers, spectral bandwidths exceeding those of commercial OCT sources are ...

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    10. Nanoplus Launches Superluminescent Eiodes (SLD) in the Spectral Band from 760 nm to 2900 nm

      Nanoplus Launches Superluminescent Eiodes (SLD) in the Spectral Band from 760 nm to 2900 nm

      nanoplus , a German manufacturer ( sales@nanoplus.us ), launches superluminescent diodes (SLD) in the spectral band from 760 nm to 2900 nm. The devices complement nanoplus well-known product portfolio of Distributed Feedback Lasers (DFB). They used their expertise as technology leader for DFB lasers to create broadband light sources in the near infrared. For more than 20 years, we have been manufacturing DFB and Fabry Perot (FP) lasers with excellent performance - the same technology is used for our SLDs. The new SLD devices combine the proven beam quality of nanoplus DFB lasers with the large spectrum of LEDs. The figures show ...

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      Mentions: Nanoplus
    11. SUPERLUM's SLD-261 modules are now available at below 660 nm wavelength

      SUPERLUM's SLD-261 modules are now available at below 660 nm wavelength

      Superlum announces an expansion of the SLD-26 wavelength to below 660 nm . They are now available at 675 nm, 665 nm and 655 nm . Compact 3-SLD lightsources with output power of 8-10 mW and spectrum width of 30 nm , currently the broadest SLD-based lightsources at this band , may be assembled by combining these SLDs by appropriate fiber couplers. Superlum is also planning introduction of a new P/N at this band, namely, medium power SLDs with spectrum width exceeding 10 nm.

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      Mentions: Superlum
    12. High-speed Time-stretch Optical Coherence Tomography (Thesis)

      High-speed Time-stretch Optical Coherence Tomography (Thesis)

      Supercontinuum sources have great potential in optical coherence tomography due to their ultrabroad spectra, which provide ultrahigh resolution images. High intensity noise of conventional supercontinuum sources, however, has been the limiting factor of widespread adoption, but the emergence of low noise supercontinuum sources promise to change this. In this thesis, both types of supercontinuum sources are tested in a spectrometer-based optical coherence tomography setup, where it is found that the low noise supercontinuum is able to produce the shot noise limited images, a feat that is not replicated by the conventional supercontinuum. Furthermore, the two types of supercontinuum sources are ...

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    13. VIS-OCT needs stable, versatile light sources

      VIS-OCT needs stable, versatile light sources

      Optical coherence tomography (OCT) is the gold standard for noninvasive retinal imaging, enabling ophthalmologists to diagnose and treat multiple ocular diseases. Compared to traditional OCT, which uses near-infrared (NIR) wavelengths of light, visible-light OCT (VIS-OCT) offers superior spatial resolution and novel functional imaging capabilities. VIS-OCT provides the most accurate means for measuring retinal oxygen saturation, a key biomarker for understanding changes in tissue metabolism associated with the pathology of various retinal diseases. Traditional OCT has dominated ophthalmic diagnostics for the past 30 years. Thanks to investment in and development of key OCT components, there is an opportunity to accelerate adoption ...

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    14. Extreme Raman red shift: ultrafast multimode nonlinear space-time dynamics, pulse compression, and broadly tunable frequency conversion

      Extreme Raman red shift: ultrafast multimode nonlinear space-time dynamics, pulse compression, and broadly tunable frequency conversion

      Ultrashort high-energy pulses at wavelengths longer than 1 µm are now desirable for a vast variety of applications in ultrafast and strong-field physics. To date, the main answer to the wavelength tunability for energetic, broadband pulses still relies on optical parametric amplification (OPA), which often requires multiple and complex stages, may feature imperfect beam quality, and has limited conversion efficiency into one of the amplified waves. In this work, we present a completely different strategy to realize an energy-efficient and scalable laser frequency shifter. This relies on the continuous red shift provided by stimulated Raman scattering (SRS) over a long ...

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    15. Electrically pumped continuous-wave O-band quantum-dot superluminescent diode on silicon

      Electrically pumped continuous-wave O-band quantum-dot superluminescent diode on silicon

      High-power, broadband quantum-dot (QD) superluminescent diodes (SLDs) are ideal light sources for optical coherence tomography (OCT) imaging systems but have previously mainly been fabricated on native GaAs- or InP-based substrates. Recently, significant progress has been made to emigrate QD SLDs from native substrates to silicon substrates. Here, we demonstrate electrically pumped continuous-wave InAs QD SLDs monolithically grown on silicon substrates with significantly improved performance thanks to the achievement of a low density of defects in the III-V epilayers. The fabricated narrow-ridge-waveguide device exhibits a maximum 3 dB bandwidth of 103 nm emission spectrum centered at the O-band together with a ...

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    16. Bandwidth enhancement in an InGaN/GaN three-section superluminescent diode for optical coherence tomography

      Bandwidth enhancement in an InGaN/GaN three-section superluminescent diode for optical coherence tomography

      In this paper, the optoelectronic properties of InGaN-based blue (430 nm) superluminescent light-emitting diodes with a multi-section, three contact design are reported. The bias conditions of the rear absorber section and gain sections are explored in terms of enhancing and maximizing spectral bandwidth. We demonstrate that broader emission can be obtained with a short circuit, rather than an open circuit absorber section, and with two active regions at different current densities as opposed to a single active contact. Under optimal drive conditions, a −3 dB linewidth of 20 nm is obtained at 430 nm. Analysis of the device emission spectrum ...

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    17. Study of low-peak-power highly coherent broadband supercontinuum generation through a dispersion-engineered Si-rich silicon nitride waveguide

      Study of low-peak-power highly coherent broadband supercontinuum generation through a dispersion-engineered Si-rich silicon nitride waveguide

      Since the first observation by Alfano and Shapiro in the 1970s [Phys. Rev. Lett. 24 , 584 (1970) [ CrossRef ] ], supercontinuum generation study has become an attractive research area in the field of broadband light source design, including its use in various applications associated with nonlinear optics in recent years. In this work, the numerical demonstration of ultrabroadband supercontinuum generation in the mid-infrared (MIR) region via the use of complementary metal-oxide semiconductor compatible Si-rich silicon nitride as the core in a planar waveguide design employing one of two materials, either L i N b O 3 LiNbO3 or M g F 2 ...

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    18. Noise reduction in supercontinuum sources for OCT by single-pulse spectral normalization

      Noise reduction in supercontinuum sources for OCT by single-pulse spectral normalization

      Supercontinuum (SC) sources offer high illumination power from a single-mode fiber with large spectral bandwidth including the visible spectrum, which is a growing application area for optical coherence tomography (OCT). However, SC spectra suffer from pulse-to-pulse variations, increasing noise in the resulting images. By simultaneously collecting a normalization spectrum, OCT image noise can be reduced by more than half (7 dB) for single pulses without any pulse averaging using only simple optical components.

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    19. Sources of optical radiation and methods for providing low-speckle optical radiation, and systems and methods using them

      Sources of optical radiation and methods for providing low-speckle optical radiation, and systems and methods using them

      The present disclosure relates more particularly to active optical fibers, amplified spontaneous emission (ASE) sources using such active optical fibers, and imaging and detection systems and methods using such ASE sources. In one aspect, the disclosure provides an active optical fiber that includes a rare earth-doped gain core configured to emit radiation at at least a peak wavelength emitted wavelength when pumped with pump radiation having a pump wavelength; a pump core surrounding the gain core; and a cladding surrounding the pump core, wherein the value M=16R.sup.2(NA).sup.2/.lamda..sup.2 in which R is ...

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    20. Supercontinuum generation in a chalcogenide all-solid hybrid microstructured optical fiber

      Supercontinuum generation in a chalcogenide all-solid hybrid microstructured optical fiber

      We report the fabrication of a chalcogenide all-solid hybrid microstructured optical fiber and its application in supercontinuum generation for the first time, to the best of our knowledge. The fiber possesses all-normal and flattened chromatic dispersion, making it highly potential for broad and coherent supercontinuum generation. By pumping the fiber with a femtosecond laser at 3, 4, and 5 µm, broad supercontinua with good spectral flatness are generated. The broadest SC spectrum extending from 2.2 to 10 µm at -20 dB level was obtained when the fiber was pumped at 5 µm with an input power of 3.9 ...

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    21. Supercontinuum light source comprising tapered microstructured optical fiber

      Supercontinuum light source comprising tapered microstructured optical fiber

      The invention relates to a supercontinuum light source comprising a microstructured optical fiber and a pump light source. The microstructured optical fiber comprises a core and a cladding region surrounding the core, as well as a first fiber length section, a second fiber length section and an intermediate fiber length section between said first and second fiber length sections. The first fiber length section comprises a core with a first characteristic core diameter. The second fiber length section comprises a core with a second characteristic core diameter, smaller than said first characteristic core diameter, where said second characteristic core diameter ...

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      Mentions: NKT Photonics
    22. Broadened Bandwidth Amplified Spontaneous Emission from Blue GaN-Based Short-Cavity Superluminescent Light-Emitting Diodes

      Broadened Bandwidth Amplified Spontaneous Emission from Blue GaN-Based Short-Cavity Superluminescent Light-Emitting Diodes

      We report broad bandwidth blue superluminescent light-emitting diodes (SLEDs) based on a short-cavity active region. The dependencies of amplified spontaneous emission (ASE) output power and gain bandwidth on cavity length were investigated in devices whose gain medium consists of a ridge waveguide with embedded InGaN/GaN quantum wells sandwiched between one etched facet coated with a high reflectivity distributed Bragg mirror and one cleaved facet with an anti-reflection coating. 250 μm-long blue SLEDs exhibit a spectral bandwidth up to 7.5 nm at 1.72 mW output power at a wavelength of 427 nm. As cavity length decreases, the bandwidth ...

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    23. GaAs-Based InPBi Quantum Dots for High Efficiency Super-Luminescence Diodes

      GaAs-Based InPBi Quantum Dots for High Efficiency Super-Luminescence Diodes

      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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    24. Ultrahigh-resolution optical coherence tomography/angiography with an economic and compact supercontinuum laser

      Ultrahigh-resolution optical coherence tomography/angiography with an economic and compact supercontinuum laser

      In this study, a Q-switch pumped supercontinuum laser (QS-SCL) is used as a light source for in vivo imaging via ultrahigh-resolution optical coherence tomography and angiography (UHR-OCT/OCTA). For this purpose, an OCT system based on a spectral-domain detection scheme is constructed, and a spectrometer with a spectral range of 635 − 875 nm is designed. The effective full-width at half maximum of spectrum covers 150 nm, and the corresponding axial and transverse resolutions are 2 and 10 µm in air, respectively. The relative intensity noise of the QS-SCL and mode-locked SCL is quantitatively compared. Furthermore, a special processing algorithm is ...

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