Frequency: Quarterly E- ISSN: 2277-6303 P- ISSN: Awaited Abstracted/ Indexed in: Ulrich's International Periodical Directory, Google Scholar, SCIRUS
"Inventi Impact: Optical Technologies" is the peer reviewed journal of Engineering & Technology. It has the research and review paper related to optical engineering and technologies, optical instruments and computational optics useful to engineers, researchers, physicists and mathematicians.
This paper presents an automatic optical equalizer based on a pair of in-house developed high efficiency, acousto-optic variable\r\noptical attenuators (AO-VOAs). The system is polarization insensitive and presents a wide bandwidth compatible with coarse\r\nwavelength division multiplexing (CWDM) requirements: 340 nm. The system operation is automatic and bidirectional and\r\nequalization is obtained in one single iteration of algorithm loop....
OFDM modulated millimeter wave (mm-wave) at 60GHz. In order to improve transmission of this system, the discrete Fourier\ntransform spread (DFT-Spread) technology and the averaging of the channel frequency response (H-averaging) technology are\napplied. The DFT-Spread technology helps to reduce the peak-to-average power ratio (PAPR) of the OFDM signal, and the Haveraging\ntechnology helps to optimize channel estimation.This is the first time that the two kinds of technologywere used together\nin this reverse modulation system. According to the simulation, the 22Gbit/s 16QAM-OFDM at 60GHz can be generated and\ntransmitted for 90km fiber transmission under the soft decision forward error correction (SD-FEC) threshold 3.8Ã?10-3.The results\nshow that the two jointed DSP algorithms can improve the reverse modulation system transmission performance obviously...
The structural modification of Ba0.5Sr0.5TiO3 (BST) nanocatalyst was successfully synthesized via sol-gel process. The BST\ncatalyst was modified by A-site (A-BST), A-B-site (A-B-BST), and B-site (B-BST) in order to investigate the effect of structurally\nmodified BST catalyst for photocatalytic decolorization of methylene blue. The structurally modified BST catalysts can increase\nthe non radiation energy such as phonon energy compared to that of BST one. The partial incorporation of the A-BST catalyst\nwas evidenced by the higher-ordered structure by increasing number of Ti4+ ions and the lattice oxygen. The A-B-BST and ABST\ncatalysts were given more electron-transfer in the TiO6 than that of BST and B-BST catalysts, respectively. The A-B-BST\ncatalyst promoted the oxidation of the lattice oxygen by holes capturing to form the chemisorbed oxygen, presenting the highest\nphotobleaching activity of methylene blue. On the other hand, more oxygen vacancies recombination of BST catalyst compared to\nthat of structurally modified BST catalysts presented the reduction of photocatalytic activity....
A monochromatic continuous millimeter-wave imaging system coupled with an infrared temperature sensor has been used to investigate artistic objects such as painting artworks or antiquities preserved at the museum of Aquitaine. Especially, 2D and 3D analyses have been performed in order to reveal the internal structure of a nearly 3500-year-old sealed Egyptian jar....
Various applications require an antenna to provide coverage in the azimuthal plane while still retaining a\nlow profile. Transformation Optics method can be used to provide novel solutions to fulfill this objective. In this paper,\nthe design of dielectric superstrate inspired from Transformation Optics has been reported which completely reorients\nthe electromagnetic waves emanating from a directive antenna in the azimuthal plane. The physical space is modeled\nusing a virtual space composed of two opposed quarter circles. It is shown analytically that a dielectric-only solution\ncan be obtained from the transformation relations. Use of shift and compression factors has been applied to the\nmaterial parameter profile to achieve the reorientation. A full wave solution has been presented which reorients\nthe radiation pattern of a classical patch antenna in the azimuthal plane. The solution can be fabricated from isotropic\ndielectric materials....
This paper presents a method for gas concentration determination based on the measurement of the refractive index dispersion of a gas near the gas resonance in the near-infrared region (NIR). The gas refractive index dispersion line shape is reconstructed from the variation in the spectral interference fringesâ?? periods, which are generated by a low-finesse Fabry-Perot interferometer during the DFB diodeâ??s linear-over-time optical frequency sweep around the gas resonance frequency. The entire sensing system was modeled and then verified experimentally, for an example of a low concentration methane-air mixture. We demonstrate experimentally a refractive index dispersion measurement resolution of ..............
The key technology and main difficulty for optical fiber intrusion pre-warning systems\n(OFIPS) is the extraction of harmful-intrusion signals. After being processed by a phase-sensitive\noptical time-domain reflectometer (-OTDR), vibration signals can be preliminarily extracted.\nGenerally, these include noises and intrusions. Here, intrusions can be divided into harmful and\nharmless intrusions. With respect to the close study of signal characteristics, an effective extraction\nmethod of harmful intrusion is proposed in the paper. Firstly, in the part of the background\nreconstruction, all intrusion signals are first detected by a constant false alarm rate (CFAR). We then\nreconstruct the backgrounds by extracting two-part information of alarm points, time and amplitude.\nThis ensures that the detection background consists of intrusion signals. Secondly, in the part of the\ntwo-dimensional Kolmogorov-Smirnov (K-S) test, in order to extract harmful ones from all extracted\nintrusions, we design a separation method. It is based on the signal characteristics of harmful\nintrusion, which are shorter time interval and higher amplitude. In the actual OFIPS, the detection\nmethod is used in some typical scenes, which includes a lot of harmless intrusions, for example\nconstruction sites and busy roads. Results show that we can effectively extract harmful intrusions....
The work presented in this paper shows that Fiber Bragg Grating (FBG) optical fiber sensors\ncan potentially be used as receivers in a long-range guided wave torsional-mode pipe inspection\nsystem. Benefits over the conventional pulse-echo method arise due to reduced total travel distance\nof the ultrasonic guided wave reflections, since reflections from defects and structural features do not\nneed to propagate a full round trip back to the transmitting collar. This is especially important in\npipe configurations with high attenuation, such as coated and buried pipelines. The use of FBGs as\nreceivers instead of conventional piezoelectric or magnetostrictive elements also significantly reduces\ncabling, since multiple FBG receivers can be placed along a single optical fiber which has a diameter\non the order of only around 100 �¼m. The basic approach and sample results are presented in the\npaper. Additionally, a brief overview of some topics in ultrasonic guided waves is presented as a\nbackground to understand the inspection problem presented here....
In this work, a linear birefringence measurement method is proposed for an optical fiber\ncurrent sensor (OFCS). First, the optical configuration of the measurement system is presented.\nThen, the elimination method of the effect of the azimuth angles between the sensing fiber and the\ntwo polarizers is demonstrated. Moreover, the relationship of the linear birefringence, the Faraday\nrotation angle and the final output is determined. On these bases, the multi-valued problem on\nthe linear birefringence is simulated and its solution is illustrated when the linear birefringence is\nunknown. Finally, the experiments are conducted to prove the feasibility of the proposed method.\nWhen the numbers of turns of the sensing fiber in the OFCS are about 15, 19, 23, 27, 31, 35, and 39,\nthe measured linear birefringence obtained by the proposed method are about 1.3577, 1.8425, 2.0983,\n2.5914, 2.7891, 3.2003 and 3.5198 rad. Two typical methods provide the references for the proposed\nmethod. The proposed method is proven to be suitable for the linear birefringence measurement in\nthe full range without the limitation that the linear birefringence must be smaller than Ãâ?¬/2....
A new method for detecting the sound pressure in air, which uses the total internal reflection at the curved interface between glass and air, is proposed, and its application to microphone is discussed. The critical angle for total reflection changes by the refractive index of air, which depends on the air density. The density changes by the sound pressure. Therefore, the sound pressure is measurable by detecting the intensity of the reflected light from the total reflection area. The sound pressure sensitivity of the proposed method is investigated theoretically and experimentally. Experimental results show that the microphone using the method is feasible though its sensitivity is low in the present stage. When the sensitivity is improved dramatically for practical use, the microphone becomes very sensitive to the surrounding conditions. A method to compensate the fluctuation of atmospheric pressure or temperature is presented....
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