Aim: Colorectal cancer (CRC) patients need CRC-specific dietary guidance, but often lack access to adequate nutritional information and support. This scoping review identified study interventions, online resources, which have been produced to support nutritional care self-management for CRC patients from diagnosis, through treatment and into survivorship and guidelines to underpin these.
Methods: The review was carried out in accordance with the JBI method for Scoping Reviews.
Digital phase-stepping shearography is a speckle interferometric technique that uses laser speckles to generate the phase map of the displacement derivatives of a stressed object, and hence can map the stresses of a deformed object directly. Conventional digital phase-stepping shearography relies on the use of video cameras of relatively lower resolution, in the order of 5 megapixels or lower, operating at a video rate. In the present work, we propose a novel method of performing high spatial resolution phase stepping shearography.
View Article and Find Full Text PDFWe report on the excitation and polarization preserved propagation of a very large effective-area (A ∼ 2240 μm) higher-order-mode in an optical fiber. A laser signal operating in the 1 μm wavelength region is transported in a Bessel-like LP mode over a 10 m long section of the polarization-maintaining higher-order-mode fiber. We observe that the light propagates through the fiber with >10 dB polarization-extinction-ratio as the fiber is coiled into circular loops of 40 cm diameter.
View Article and Find Full Text PDFWe demonstrate operation of a cladding-pumped hybrid ytterbium-doped HOM fiber amplifier and reconversion of the HOM output to Gaussian-like beam by using an axicon based reconversion system. The amplifier was constructed by concatenating single-mode and HOM ytterbium-doped double clad fibers, and was excited by a common multimode pump source. A continuous wave (cw) input signal of 97mW was amplified to 100W at the amplifier output, which yielded a gain of more than 30dB.
View Article and Find Full Text PDFHigher-order-mode (HOM) fibers guiding light in large-effective-area (A) Bessel-like modes have recently generated great interest for high-power laser applications. A polarization-maintaining (PM) version of HOM fibers can afford the added possibility of coherent beam combination, improved material processing, and polarization multiplexing of high-power fiber lasers. We report a PM-HOM fiber for guiding Bessel-like modes with A ranging from 1200-2800 μm.
View Article and Find Full Text PDFWe demonstrate a seven-core erbium-doped fiber amplifier in which all the cores were pumped simultaneously by a side-coupled tapered multimode fiber. The amplifier has multicore (MC) MC inputs and MC outputs, which can be readily spliced to MC transmission fiber for amplifying space division multiplexed signals. Gain over 25 dB was obtained in each of the cores over a 40-nm bandwidth covering the C-band.
View Article and Find Full Text PDFA cladding pumped multicore erbium-doped fiber amplifier for simultaneous amplification of 6 channels is demonstrated. Peak gain over 32 dB has been obtained at a wavelength of 1560 nm and the bandwidth measured at 20-dB gain was about 35 nm. Numerical modeling of cladding pumped multicore erbium-doped amplifier was also performed to study the properties of the amplifier.
View Article and Find Full Text PDFWe demonstrate parallel fabrication of seven fiber distributed feedback (DFB) lasers in a hexagonally arrayed multicore core Er doped fiber with 40 μm core spacing. DFB grating cavities 8 cm long and operating near 1545 nm were fabricated with a single UV inscription exposure. We observed dual polarization, single longitudinal mode operation with a linewidth below 300 kHz for each laser.
View Article and Find Full Text PDFElemental analyses of kohl (stone) samples collected from three different parts of the world were performed using laser-induced breakdown spectroscopy (LIBS). The analyses indicated that lead (Pb), copper (Cu), silver (Ag), iron (Fe), calcium (Ca), aluminum (Al), silicon (Si), and sodium (Na) were present in all the kohl samples. In addition to these elements, the sample from Madina, Kingdom of Saudi Arabia (KSA), contained the elements tin (Sn), zirconium (Zr), and antimony (Sb).
View Article and Find Full Text PDFWe experimentally demonstrate series of identical two, three, and five coupled high Q-factor surface nanoscale axial photonics (SNAP) microresonators formed by periodic nanoscale variation of the optical fiber radius. These microresonators are fabricated with a 100 μm period along an 18 μm radius optical fiber. The axial FWHM of these microresonators is 80 μm and their Q-factor exceeds 10(7).
View Article and Find Full Text PDFWe demonstrate a single-frequency Brillouin distributed feedback laser (DFB). The DFB laser cavity was a 12.4 cm long fiber Bragg grating with a π-phase shift offset from the grating center.
View Article and Find Full Text PDFRandom perturbations play an important role in the crosstalk of multicore fibers, and can be captured by statistical coupled-mode calculations. In this approach, phase matching contributes a multiplicative factor to the average crosstalk, depending on the perturbation statistics and any intentional heterogeneity of neighboring cores. The impact of perturbations is shown to be qualitatively different depending on whether they are gradually varying, or have short-length (centimeter-scale) variations.
View Article and Find Full Text PDFA multicore erbium-doped fiber (MC-EDF) amplifier for simultaneous amplification in the 7-cores has been developed, and the gain and noise properties of individual cores have been studied. The pump and signal radiation were coupled to individual cores of MC-EDF using two tapered fiber bundled (TFB) couplers with low insertion loss. For a pump power of 146 mW, the average gain achieved in the MC-EDF fiber was 30 dB, and noise figure was less than 4 dB.
View Article and Find Full Text PDFWe demonstrate fiber distributed feedback (DFB) lasers using Raman gain in two germanosilicate fibers. Our DFB cavities were 124 mm uniform fiber Bragg gratings with a π phase shift offset from the grating center. Our pump was at 1480 nm and the DFB lasers operated on a single longitudinal mode near 1584 nm.
View Article and Find Full Text PDFOpt Express
September 2010
We propose and experimentally demonstrate monitoring of a fiber fuse in real time using an optical time domain reflectometer (OTDR). When a fuse starts, a weak reflection of light occurs from the leading edge of the fuse where plasma and voids are being formed in the core. In this work, we examined the possibility of monitoring a fiber fuse from a remote location using an OTDR.
View Article and Find Full Text PDFWe report broadening in spectrum as light is backreflected from a propagating fiber fuse. The formation of micrometer-size voids results in periodic changes in Fresnel reflection occurring in the leading part of the fuse. High-resolution measurement of the optical spectrum via heterodyne detection revealed an upshift (Doppler shift) in the optical frequency and discrete frequency components that are characteristic of amplitude modulation due to periodic void formation.
View Article and Find Full Text PDFThe properties of backreflected light due to voids in a fiber fuse were studied using optical coherence-domain reflectometry of a damaged fiber and real-time monitoring of the electrical (RF) and optical frequency spectrum. Light reflected backward at the interface of a propagating fiber fuse acquired low-frequency broadband amplitude modulation, which can be detected remotely at the source end, using an RF spectrum analyzer. For the light backreflected during propagation of a fuse, we derived an analytical expression that well explained the spectral features observed experimentally in the RF spectrum.
View Article and Find Full Text PDFIn this paper, we discuss the multicast efficiency issue in the optical layer multicast. A 1-to-8 phase-preserved different phase-shifted keying (DPSK) wavelength multicast is experimentally demonstrated using four-wave mixing (FWM) in a piece of Bismuth highly nonlinear fiber (Bi- HNLF). DPSK signal is successfully delivered from one wavelength to up to eight different wavelengths using only three pumps.
View Article and Find Full Text PDFAll-optical cross-phase modulation through the intersubband transition in an InGaAs/AlAsSb coupled quantum well was examined by using a sinusoidal intensity-modulated pump. For probe waves in the wavelength range of 1330-1620 nm and a pump modulation at a repetition rate of 76 GHz, cross-phase modulation (XPM) occurred with an efficiency eta, of 0.653-0.
View Article and Find Full Text PDFWe demonstrate superluminal propagation of optical pulses with amplification in optical fibers based on stimulated Brillouin scattering. A triple gain peak configuration is used for the generation of narrowband anomalous dispersion in 2 m tellurite glass fiber, where the group index change as much as -1.19 is achieved with 6.
View Article and Find Full Text PDFMid-infrared radiation in the 5-18-mum range has been obtained by difference frequency generation in a AgGaSe(2) crystal by pumping with the output of a type I LiNbO(3) optical parametric oscillator (OPO). Here we suggest the use of a LiTaO(3) retarder to achieve an orthogonal state of polarization between OPO outputs that are necessary for efficient pumping of a AgGaSe(2) crystal. Several tens of kilowatts of peak power near 8 mum and continuously tunable operation in the above range have been obtained.
View Article and Find Full Text PDFWe demonstrate the generation of optical pulses at a repetition rate of 64 GHz directly from a frequency-modulated (FM) mode-locked fiber laser. This is achieved by phase modulation at 16 GHz and by initiating of higher-order FM mode locking by use of an intracavity Fabry-Perot filter with a free spectral range of 64 GHz. This process yielded transform-limited pulses with a width of 3.
View Article and Find Full Text PDFFourier synthesis of optical-pulse trains based on optical phase locking of three cw semiconductor lasers has been demonstrated by use of a semiconductor optical amplifier as a four-wave mixer. The temporal waveforms of the pulse trains were directly observed at a repetition rate of 9.6 GHz by a fast sampling oscilloscope.
View Article and Find Full Text PDFWe describe a novel method, based on asymmetric modulation in a Sagnac interferometer, that measures the chromatic dispersion of single-mode fibers. The interferometer incorporates a phase modulator and a test fiber, so the dispersion can be determined from the interference fringe seen when a sweep rf signal is applied to the modulator. This technique provides picosecond temporal resolution without the need for any fast diagnostic equipment and is capable of accurately measuring the average dispersion of fibers several kilometers long.
View Article and Find Full Text PDFFourier synthesis of ultrafast optical-pulse trains was demonstrated based on optical phase locking of three independent continuous-wave semiconductor lasers. Pulse repetition frequencies as high as 1.81 THz were limited by the gain bandwidth of an erbium-doped fiber amplifier.
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