1. Articles in category: Broadband Sources

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    1. Supercontinuum generation in silicon nanowire embedded photonic crystal fibers with different core geometries

      Supercontinuum generation in silicon nanowire embedded photonic crystal fibers with different core geometries

      We design various silicon nanowire embedded photonic crystal fibers (SN-PCFs) with different core geometries, namely, circular, rectangular and elliptical using finite element method. Further, we study the optical properties such as group velocity dispersion (GVD), third order dispersion (TOD) of x and y-polarized modes and effective nonlinearity for a wavelength range from 0.8 to 1.6 μm. The proposed structure exhibits almost flat GVD (0.8 to 1.2 μm wavelength), zero GVD (≈ 1.31 μm) and small TOD (0.00069 ps 3 /m) at 1.1 μm wavelength and high nonlinearity (2916 W -1 m -1 ) at 0 ...

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    2. Characterizing the resolvability of real superluminescent diode sources for application to optical coherence tomography using a low coherence interferometry model

      Characterizing the resolvability of real superluminescent diode sources for application to optical coherence tomography using a low coherence interferometry model

      The axial resolution is a critical parameter in determining whether optical coherent tomography (OCT) can be used to resolve specific features in a sample image. Typically, measures of resolution have been attributed to the light source characteristics only, including the coherence length and the point spread function (PSF) width of the OCT light sources. The need to cost effectively visualize the generated PSF and OCT cross-correlated interferogram (A-scan) using many OCT light sources have led to the extrinsic evolution of the OCT simulation model presented. This research indicated that empirical resolution in vivo , as well as depending on the light ...

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    3. Fabrication and Characteristics of Ce-Doped Fiber for High-Resolution OCT Source

      Fabrication and Characteristics of Ce-Doped Fiber for High-Resolution OCT Source

      The fabrication of Ce-doped fibers (CeDFs) is demonstrated by drawing-tower method employing rod-in-tube technique. The fluorescence spectrum of CeDFs with a 16-μm core exhibited a 160-nm broadband emission with 1.45-μm axial resolution. This CeDF may be functioned as a high-resolution light source for optical coherence tomography applications.

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    4. Yale University Receives NIH Grant for Development of a New Light Sources for Parallel Optical Coherence Tomography

      Yale University Receives NIH Grant for Development of a New Light Sources for Parallel Optical Coherence Tomography

      Yale University Receivesd a 2014 NIH Grant for $201,881 for Development of a New Light Sources for Parallel Optical Coherence Tomography. The principal investigator is Michel Choma. The program began in 2013 and ends in 2015. Below is a summary of the proposed work. The ability of optical coherence tomography (OCT) to perform high-speed, micron-scale, cross-sectional imaging has transformed ophthalmic medicine and has the potential to transform cardiovascular, gastrointestinal, pulmonary, and dermatological medicine. Current OCT systems use raster scanning, a serial method for acquiring depth reflectivity profiles at different locations on a sample. Shifting the paradigm fro serial to ...

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    5. Numerical analysis of AlGaAs/GaAs multi-quantum well superluminescent diodes

      Numerical analysis of AlGaAs/GaAs multi-quantum well superluminescent diodes

      In this paper, we have investigated numerically AlGaAs/GaAs multi-quantum well superluminescent diodes. In these devices the dependence of optical gain, output power on the cavity length and the density states have been analyzed. It is observed that the optical gain and its FWHM bandwidth increase with increasing the density state. Furthermore, the output power increases with increasing the cavity length, whereas the FWHM bandwidth decreases.

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    6. Feature Of The Week 6/29/14: Development of a high power supercontinuum source in the 1.7 um wavelength region for highly penetrative ultrahigh-resolution optical coherence tomography

      Feature Of The Week 6/29/14: Development of a high power supercontinuum source in the 1.7 um wavelength region for highly penetrative ultrahigh-resolution optical coherence tomography

      Optical coherence tomography (OCT) is an essential imaging technique especially in ophthalmology. However, the shallow penetration depth of about 1-2 mm limits the expansion of OCT applications. Recently, the OCT systems operating in 1.7 um wavelength region have been demonstrated to improve the penetration depth. In the longer wavelength region, the signal attenuation due to Rayleigh scattering is reduced compared to that in the conventional 0.8-1.3 um wavelength region. In this work, the authors developed a high power supercontinuum (SC) source at a center wavelength of 1.7 um to demonstrate highly penetrative ultrahigh resolution (UHR) OCT ...

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    7. Short cavity active mode locking fiber laser for optical sensing and imaging

      Short cavity active mode locking fiber laser for optical sensing and imaging

      We demonstrate a highly linear wavenumber- swept active mode locking (AML) fiber laser for optical sensing and imaging without any wavenumber-space resampling process. In this all-electric AML wavenumber-swept mechanism, a conventional wavelength selection filter is eliminated and, instead, the suitable programmed electric modulation signal is directly applied to the gain medium. Various types of wavenumber (or wavelength) tunings can be implemented because of the filter-less cavity configuration. Therefore, we successfully demonstrate a linearly wavenumber-swept AML fiber laser with 26.5 mW of output power to obtain an in-vivo OCT image at the 100 kHz swept rate.

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    8. Supercontinuum generation in nonlinear fibers using high-energy figure-of-eight mode-locked fiber laser for SD-OCT application

      Supercontinuum generation in nonlinear fibers using high-energy figure-of-eight mode-locked fiber laser for SD-OCT application

      Generation of flat and broadband supercontinum is demonstrated in an all fiber system using the high-energy noise-like pulses from a stable figure-of-eight fiber laser and nonlinear fibers. This SC source is successfully applied to the spectral domain optical coherence tomography (SD-OCT). The axial resolution is significantly improved compared with the case of the superluminescent diode source. SD-OCT imaging is also demonstrated.

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    9. Maximizing the bandwidth of coherent, mid-IR supercontinuum using highly nonlinear aperiodic nanofibers

      Maximizing the bandwidth of coherent, mid-IR supercontinuum using highly nonlinear aperiodic nanofibers

      We describe in detail a new procedure of maximizing the bandwidth of mid-infrared (mid-IR) supercontinuum (SC) in highly nonlinear microstructured As 2 Se 3 and tellurite aperiodic nanofibers. By introducing aperiodic rings of first and secondary air holes into the cross-sections of our microstructured fiber designs, we achieve flattened and all-normal dispersion profiles over much broader bandwidths than would be possible with simple periodic designs. These fiber designs are optimized for efficient, broadband, and coherent SC generation in the mid-IR spectral region. Numerical simulations show that these designs enable the generation of a SC spanning over 2290 nm extending from ...

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    10. Supercontinuum generation in optical fibers and its biomedical applications

      Supercontinuum generation in optical fibers and its biomedical applications

      A microstructured optical fiber was first used in 2000 for supercontinuum generation. Since then, enormous progress has been made in understanding, controlling, and marketing fiber-based supercontinuum sources. In particular, biomedical applications of such sources are revolutionizing the field of medical imaging. In this talk I review the recent progress in this area and describe how a supercontinuum can be employed for biomedical imaging using the techniques known as coherent anti-Stokes Raman scattering, stimulated emission-depletion microscopy, and optical coherence tomography.

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    11. Supercontinuum Promises Game-Changing New Tools for Medicine, Research, More

      Supercontinuum Promises Game-Changing New Tools for Medicine, Research, More

      Supercontinuum generation has already found uses in chemistry and biology, but its discoverer says what's on the horizon is even more exciting. The technology is featured in new freely accessible multimedia presentations published by SPIE, the international society for optics and photonics.

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    12. Photonic Device And Optical Coherence Tomography Apparatus Including The Photonic Device As Light Source

      Photonic Device And Optical Coherence Tomography Apparatus Including The Photonic Device As Light Source

      Provided is a photonic device in which emission intensity in a short wavelength region is suppressed even in the case of increasing carrier injection density so as to obtain a wide spectrum half-maximum width as well as a high output. The photonic device includes: a first cladding layer; a second cladding layer; and an active layer including an emitting layer and a barrier layer and being provided between the first cladding layer and the second cladding layer, the emitting layer emitting light in a spectrum having a center wavelength λc and a spectrum half-maximum width Δλ, in which at least one ...

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    13. Light Source And Optical Coherence Tomography Apparatus Including The Light Source

      Light Source And Optical Coherence Tomography Apparatus Including The Light Source

      A light source includes an upper electrode layer, a lower electrode layer, and an active layer interposed therebetween. At least one of the upper and lower electrode layers is divided into a plurality of electrodes separated from each other in an in-plane direction of the active layer. The separated electrodes independently inject current into a plurality of different regions in the active layer. The light source emits light by injecting current from the upper and lower electrode layers into the active layer, guide the light in the in-plane direction, and output the light. The plurality of different regions in the ...

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    14. Optical Semiconductor Device, Driving Method Thereof, And Optical Coherence Tomography Apparatus Having The Optical Semiconductor Device

      Optical Semiconductor Device, Driving Method Thereof, And Optical Coherence Tomography Apparatus Having The Optical Semiconductor Device

      The present invention provides an optical semiconductor device which can make a wavelength band of emitted light wider than that of a conventional optical semiconductor device. The optical semiconductor device includes: an active layer including a multiple quantum well structure; and at least one electrode pair for injecting an electric current into the active layer, wherein the multiple quantum well structure has a first quantum well and a second quantum well which is different from the first quantum well, and the first quantum well and the second quantum well are mutually different in at least two out of a composition ...

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    15. Filtered ASE swept source for OCT medical imaging

      Filtered ASE swept source for OCT medical imaging

      An integrated swept wavelength optical source uses a filtered ASE signal with an optical amplifier and tracking filter. This source comprises a micro optical bench, a source for generating broadband light, a first tunable Fabry Perot filter, installed on the bench, for spectrally filtering the broadband light from the broadband source to generate a narrowband tunable signal, an amplifier, installed on the bench, for amplifying the tunable signal, and a second tunable Fabry Perot filter, installed on the bench, for spectrally filtering the amplified tunable signal from the amplifier. A self-tracking arrangement is also possible where a single tunable filter ...

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    16. Development of a high power supercontinuum source in the 1.7 μm wavelength region for highly penetrative ultrahigh-resolution optical coherence tomography

      Development of a high power supercontinuum source in the 1.7 μm wavelength region for highly penetrative ultrahigh-resolution optical coherence tomography

      We developed a high power supercontinuum source at a center wavelength of 1.7 μm to demonstrate highly penetrative ultrahigh-resolution optical coherence tomography (UHR-OCT). A single-wall carbon nanotube dispersed in polyimide film was used as a transparent saturable absorber in the cavity configuration and a high-repetition-rate ultrashort-pulse fiber laser was realized. The developed SC source had an output power of 60 mW, a bandwidth of 242 nm full-width at half maximum, and a repetition rate of 110 MHz. The average power and repetition rate were approximately twice as large as those of our previous SC source [ 20 ]. Using the developed ...

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    17. III-V Quantum Dot Lasers Grown Directly on Silicon

      III-V Quantum Dot Lasers Grown Directly on Silicon

      The University of California Santa Barbara (UCSB) has grown 1.3 μm-wavelength indium arsenide (InAs) quantum dot (QD) lasers directly on silicon, with record device performance. The breakthrough approach promises an alternative to wafer bonding lasers grown on native substrates, which, in return, could help advance silicon photonics by way of cheap large-scale growth and high-performing QD optoelectronics. The new QD lasers consist of billions of nanometer-sized indium arsenide (InAs) quantum dots, cladded on either side by gallium-arsenide-(GaAs)-related compounds. The structure is grown using a technique called molecular beam epitaxy (MBE) on germanium/silicon substrates. “The excitement from ...

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    18. NKT Photonics releases World’s most affordable supercontinuum laser

      NKT Photonics releases World’s most affordable  supercontinuum laser

      NKT Photonics, the leading manufacturer of supercontinuum sources, releases new SuperK COMPACT – the World’s most affordable supercontinuum fiber laser. The new source provides single mode, fiber delivered light in the entire 450-2400nm range and, unlike most supercontinuum sources on the market, the laser can be triggered externally and synced with low jitter from single shot up to 20 kHz. The previous generation COMPACT can be found in laboratories around the World where it is the daily driver within applications like component characterization, test & measurement and spectroscopy, or simply as a general purpose laboratory white light source. However, the low ...

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      Mentions: NKT Photonics
    19. Ultrahigh-Resolution Optical Coherence Tomography with LED-Phosphor-Based Broadband Light Source

      Ultrahigh-Resolution Optical Coherence Tomography with LED-Phosphor-Based Broadband Light Source

      This study proposed and demonstrated the potential use of LED phosphors as a simple light source for ultrahigh-resolution spectral-domain optical coherence tomography (SD-OCT) in the visible regime. Excited by a 405 nm diode laser, broadband spontaneous emission from three different LED phosphors was generated. The best axial resolution was 1.7 µm in air, and finally, corresponding three-dimensional (3D) ultrahigh-resolution SD-OCT imaging was performed with the proposed broadband light source.

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    20. Novel waveguide increases superluminescent output

      Novel waveguide increases superluminescent output

      A partnershipbetween Polish and Japanese researchers claims to have set a new benchmark for the combination of output power and smoothness of spectral output for GaN superluminescent diodes. This team’s emitter features a ‘J-shaped’ waveguide and could be used in fibre-optic gyroscopes and optical coherence tomography. Both applications require a light source that combines a high degree of spatial coherence with low time coherence. These conditions are met with the superluminescent diodes. They were developed in the arsenide material system in the 1970s, but the shorter wavelengths emitted by GaN-based materials are beneficial.

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    21. Laser plus phosphor emits white light without

      Laser plus phosphor emits white light without

      Combining a blue-emitting indium gallium nitride (InGaN) LED with a yellow YAG phosphor has produced one of most successful commercial photonic devices ever—the white-light LED. But there is a problem: InGaN LEDs suffer from efficiency droop, in which their efficiency at high currents, and therefore high optical outputs, is lower than that for low currents and optical outputs. However, other InGaN light sources—blue- and near-UV-emitting laser diodes—do not suffer from this problem. With this in mind, researchers at the University of California, Santa Barbara (UCSB), led by material scientists Kristin Denault and Michael Cantore, have combined laser ...

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    22. High-Optical-Power InGaN Superluminescent Diodes with “j-shape” Waveguide

      High-Optical-Power InGaN Superluminescent Diodes with “j-shape” Waveguide

      We demonstrate blue-violet InGaN superluminescent diodes (SLDs) with bent-waveguide (j-shape) geometry, emitting optical power exceeding 200 mW for SLD with 1-mm-long waveguide. The adopted j-shape geometry prevents devices from lasing, even at the highest applied currents (450 mA). However, high-resolution measurements reveal the appearance of spectral ripples at currents on the order of 250 mA. The maximum output power increases with the waveguide length

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    23. Coherent Launches Turnkey 550 mW, Sub-10 fs Laser

      Coherent Launches Turnkey 550 mW, Sub-10 fs Laser

      The latest member of the Vitara family ofextreme performance, closed-box, ultrafast oscillators from Coherent, Inc. (Santa Clara, CA) – the Vitara UBB –provides hands-free access to pulsewidths under 10 femtoseconds, with options below 8 fs on request. Vitara UBB (Ultra BroadBand) achieves its short transform-limited pulsewidths because of its very broad bandwidth (> 200 nm at the -10 dB point). Its unique combination of short pulsewidths, broad bandwidth, high reliability and ease-of-use make Vitara UBB the ideal laser for applications in terahertz pulse generation, optical coherence tomography (OCT), pump-probe spectroscopy, multiplexed CARS spectroscopy, non-linear microscopic imaging and seeding short-pulse amplifiers. By integrating ...

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    24. Broadband wavelength swept source combining a quantum dot and a quantum well SOA in the wavelength range of 1153–1366 nm

      Broadband wavelength swept source combining a quantum dot and a quantum well SOA in the wavelength range of 1153–1366 nm

      wide tuning range wavelength swept laser for high axial resolution optical coherence tomography reported. Here, a parallel configuration of a quantum dot semiconductor optical amplifier (SOA) and a quantum well SOA is utilised for broadband optical source. The total scanning range of over 210 nm (192 nm at 10 dB) from 1153 to 1366 nm is reported. To investigate the feasiblity of the swept light source, demonstrated is an optical frequency domain imaging (OFDI) system. The system sensitivity of 101 dB is reported and axial resolution of 6.0 µm in air is achieved. Finally, ex vivo OFDI imaging of ...

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      Mentions: Samsung
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