We report an easy-to-build, compact, and low-cost optical fiber refractive index sensor. It consists of a single fiber loop whose transmission spectra exhibit a series of notches produced by the resonant coupling between the fundamental mode and the cladding modes in a uniformly bent fiber. The wavelength of the notches, distributed in a wavelength span from 1,400 to 1,700 nm, can be tuned by a...

As shown in Fig. 1, we have measured the spectral sensitivity functions for 28 cameras, including professional DSLRs, point-and-shoot, industrial and mobile cameras (i.e.Nokia N900), using a monochromator and a spectrometer PR655. At each wavelength, the camera spectral sensitivity in RGB channels is calculated by c(λ) = d(λ)/(r(λ) · t(λ)), where d is the raw data recorded by the camera, r is t...

Based on the well-known electron coherent tunneling phenomenon, by simulation, a photonic tunneling filter fabricated in an optical waveguide is proposed. The Bragg grating structure is applied as the photonic barrier. Two photonic barriers confine a coherent resonance cavity or photon-quantum-well. We report an asymmetric-barrier structure with opposite phase. In this configuration, the centra...

In hyperspectral remote sensing, sensors acquire reflectance values at many different wavelength bands, to cover a complete spectral interval. These measurements are strongly correlated and no new information might be added when increasing the spectral resolution. Moreover, the higher number of spectral bands increases the complexity of a classification task. Therefore, feature extraction is a ...

In this paper, design of the RII triple-clad structure as a dispersion flattened optical fiber including small pulse broadening factor as well as small dispersion and its slope applicable in broadband and fast communication is considered. The proposed optimization technique is based on the Genetic Algorithms (GA) consisting suitable fitness function for each application. The putting forward des...

The results of spectral measurements of the daily near-noon surface direct solar ultraviolet radiation in the wavelength range of 295–345 nm obtained in Irkutsk (East Siberia) for the time interval of 1998–2000 are presented. For the period under consideration, the seasonal UV radiation variations are analysed that are associated with the total ozone dynamics, the transition of cyclonic and ant...

In this paper, a new structure is provided for the dispersion compensating photonic crystal fibers in order to broaden the chromatic dispersion and increase the dispersion compensating capability in a wide wavelength range. In the structure, putting elliptical holes in the first ring of the inner core clad of a dispersion compensating fiber of the hexagonal lattice, increases the wavelength ran...