1. Articles in category: Broadband Sources

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    1. 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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    2. 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
    3. 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
    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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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    10. 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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    11. 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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    12. 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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    13. 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
    14. 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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    15. 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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    16. 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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    17. Efficient supercontinuum generation enabled by dispersion engineering in a dual-core waveguide

      Efficient supercontinuum generation enabled by dispersion engineering in a dual-core waveguide

      A compact dual-core waveguide is proposed for efficient supercontinuum generation, in which the use of Si-rich nitride and titanium dioxide provides a large enough index contrast for dispersion engineering. Strong anomalous group velocity dispersion is obtained over a wide bandwidth of 1860 nm which greatly reduces the dispersion length. The nonlinear length can also be significantly decreased due to high nonlinear Kerr index of Si-rich nitride. As a consequence, it could facilitate octave-spanning supercontinuum generation from 1160 to 2385 nm in a greatly reduced propagation distance, as short as 165μm . It is more than one order of magnitude shorter ...

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    18. A Step-Index Silicate Nonlinear Fiber With All Normal Flattened Dispersion for Coherent Supercontinuum

      A Step-Index Silicate Nonlinear Fiber With All Normal Flattened Dispersion for Coherent Supercontinuum

      A step-index silicate fiber with all normal flat dispersion was fabricated. Coherent supercontinuum (SC) spectrum spanning 1200 to 2000 nm was generated in a 5 cm silicate fiber pumped at 1560 nm. The numerical simulation result agreed with the experiment result. Also, highly coherent SC spectrum spanning from 1100 to 2100 nm with flatness <7 dB generated in the fiber with 57 kW pumping power according to simulation. The step-index silicate fiber is not only easy to prepare but also a promising candidate to achieve all-fiber structure for coherent SC.

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    19. Numerical investigation on coherent mid-infrared supercontinuum generation in chalcogenide PCFs with near zero flattened all-normal dispersion profiles

      Numerical investigation on coherent mid-infrared supercontinuum generation in chalcogenide PCFs with near zero flattened all-normal dispersion profiles

      We present a novel design of all-normal flat near zero dispersion chalcogenide photonics crystal fiber (PCF) for mid-infrared supercontinuum (SC) generation. The proposed PCF with a core made of As<sub>2</sub>Se<sub>3</sub> glass and uniform air holes in the cladding is selectively filled with As<sub>2</sub>S<sub>5</sub> glass. By carefully engineering the PCF with an all-normal flat near zero dispersion profile, the anomalous-dispersion soliton effects are reduced, enabling broadband highly coherent SC generation. We also investigate the impacts of the pulse parameters on the SC generation. Broadband SCs covering 1 ...

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    20. Highly coherent supercontinuum generation in CS2 infiltrated single-core optical fiber

      Highly coherent supercontinuum generation in CS2 infiltrated single-core optical fiber

      As is generally known, broad-band near-infrared Supercontinuum (SC) is significant for the applications such as pump-probe spectroscopy, nonlinear spectroscopy, frequency combs, or nonlinear optical parametric amplification. We present the first detailed demonstration of approximate near-infrared, octave-spanning SC generation in all-normal dispersion CS2 single-hole liquid core optical fiber (LCOF). By solving the generalized nonlinear Schrödinger equation, the SC at different parameters can be calculated. The influence of important parameters including but not limited to fiber core-diameter, pump wavelength, pump power, and pulse width, on the supercontinuum generation (SCG) of CS2 infiltrated LCOF can be analyzed for optimization of near-infrared SC ...

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    21. Generation and characterization of mid-infrared supercontinuum in polarization maintained ZBLAN fibers

      Generation and characterization of mid-infrared supercontinuum in polarization maintained ZBLAN fibers

      We present mid-infrared (MIR) supercontinuum generation in polarization-maintained ZBLAN fibers pumped by 2 µm femtosecond pulses from a Tm:YAP regenerative amplifier. A stable supercontinuum that spreads from 380 nm to 4 µm was generated by coupling only 0.5 µJ pulse energy into an elliptical core ZBLAN fiber. The supercontinuum was characterized using cross-correlation frequency-resolved optical gating (XFROG). The complex structure of the XFROG trace due to the pulse-to-pulse spectrum instability have been fixed by reducing the length of the applied fibers or improving the quality of the incident pulse spectrum

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    22. Chalcogenide-glass polarization-maintaining photonic crystal fiber for mid-infrared supercontinuum generation

      Chalcogenide-glass polarization-maintaining photonic crystal fiber for mid-infrared supercontinuum generation

      In this paper, we report the design and fabrication of a highly birefringent polarization-maintaining photonic crystal fiber (PM-PCF) made from chalcogenide glass, and its application to linearly-polarized supercontinuum (SC) generation in the mid-infrared region. The fiber was drawn using the casting method from As38Se62 glass which features a transmission window from 2 to 10 µm and a high nonlinear index of 1.13×10-17 m2 /W. It has a zero-dispersion wavelength around 4.5 µm and, at this wavelength, a large birefringence of 6×10-4 and consequently strong polarization maintaining properties are expected. Using this fiber, we experimentally demonstrate supercontinuum ...

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    23. EXALOS Introduces RGB Modules for Augmented Reality and Head-up Display Applications

      EXALOS Introduces RGB Modules for Augmented Reality and Head-up Display Applications

      Schlieren, Switzerland, May 6 th , 2019. EXALOS, the world’s leading developer of visible Superluminescent Light Emitting Diodes (SLEDs), has expanded its product porfolio with the introduction of a compact RGB SLED module that will enable the advancement of micro-display architectures for augmented reality (AR) and head-up displays (HUDs). The RGB module constitutes three SLED chips housed in a 14-pin butterfly package (20.8 mm x 1.7 mm) with a total output power of about 30 mW (~ 10 mW/color), which corresponds to a total luminous flux of 5 lm. The individual chips (635 nm (R), 510 nm (G ...

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      Mentions: Exalos Kevin Hsu
    24. Supercontinuum light source comprising microstructured optical fiber

      Supercontinuum light source comprising microstructured optical fiber

      The invention relates to a microstructured optical fiber for generating supercontinuum light upon feeding of pump light. The light can be incoherent light. The microstructured optical fiber has a first section and a second section, where the first and second sections have one or more different features. The invention also relates to a supercontinuum source comprising a microstructured optical fiber according to the invention.

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      Mentions: NKT Photonics
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