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0030-4026

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    Optical solitons with generalized anti–cubic nonlinearity having multiplicative white noise by Itô Calculus

    Zayed E.M.E.Shohib R.M.A.Alngar M.E.M.Biswas A....
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHObjective: The current work is about recovering solitons with generalized anti–cubic nonlinearity as well as multiplicative white noise by the usage of Itô Calculus for the first time. Methods: The Jacobi's elliptic function approach and the modified Kudryashov's algorithm are collectively implemented to acquire optical solitons that are exhibited after a thorough discussion on the intro to the model together with the prelims on mathematical analysis. Results: Dark, singular, bright–singular and bright solitons stem from the integration approaches. These solitons are extracted with the usage of the certain constraints. Conclusion: A governing model equation is newly structured in the current work. The phase component of the solitons is where the effect of white noise gets reflected. Later, this work would be extended to birefringent fibers as modeled by AC nonlinearity with the effect of white noise included. Further along, the results would be recovered for the model with DWDM topology.
      原文链接:
    • NSTL

    The role of Ag NPs in PVA electrospun NFs for ultra-high sensitivity photodetector

    Hawy H.M.Ali I.M.
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHThis work aimed to produce PVA and PVA/Ag nanofibers ultra-high sensitivity photodetector by electrospinning. The electrospinning process was used to successfully prepare PVA nanofibers and a PVA-Ag nanofiber composite. FE-SEM, XRD, UV, I-V characterizations are used to study the morphological, structural, optical, and electrical properties of the material. In contrast, the PVA-Ag nanofiber composite film displayed a cubic structure with favored orientation (200) that indicated the presence of Ag NPs in the PVA-Ag nanofibers film. While the optical energy gap for PVA was 3.96 eV, it was only 2.14 eV for PVA-Ag nanofibers composite film, making this composite sensitive to visible light, particularly green light at 550 nm with a 65% photosensitivity. The optical energy gap of PVA-Ag nanofibers composite was used to tailor this film from the ultraviolet to the visible spectrum.
      原文链接:
    • NSTL

    Temporal evolution characteristics and mechanism analysis of CCD breakdown induced by nanosecond and picosecond pulse lasers

    Kou Z.Li Y.Wang G.Li K....
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHStudies on the interaction between laser irradiation and charge-coupled devices (CCDs) have been reported to potentially bring new opportunities in the field of photoelectric countermeasures. It is known that the complete failure of CCD caused by pulsed laser originates from the destruction of CCD internal structure, but the detailed damage mechanism of laser-induced CCD breakdown is still a dilemma. Here, the thermal-mechanical coupling model of CCD irradiated by laser is established by finite element method, and the damage threshold and damage characteristics of CCD in point damage, line damage, black-and-white split screen and complete damage stages are characterized. The results show that the temperature rise effect of silicon substrate damage is predominant in the lateral direction, which increases by 300–3000 K; while it only increases by 300–400 K in the longitudinal direction. The complete damage threshold of CCD irradiated by nanosecond laser is 509 mJ/cm2; while that irradiated by picosecond laser is 190 mJ/cm2. When the silicon dioxide insulation layer is completely ablated, CCD completely fails due to the clock confusion caused by a short circuit between silicon electrodes.
      原文链接:
    • NSTL

    Investigation on the optical characteristic of calcite crystal and α-BBO crystal in direct third-harmonic generation process

    Shi M.Pan J.Lin W.
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHCalcite crystal and α-BBO crystal of which the microstructure possesses symmetric center with delocalized π bond were selected to produce phase-matched direct third-harmonic. In order to obtain a high third-order nonlinear conversion efficiency, the parameters including the walk-off angles, phase-matching angles, acceptance angles, acceptance wavelengths and group-velocity index in calcite crystal and α-BBO crystal were calculated within I (ooo→e), II (ooe→e) and III (oee→e) phase-matching types. The tinier walk-off angle and the larger acceptance angle in α-BBO crystal may lead to a better third-order nonlinear interaction in UV region. The smaller phase-matching angle in calcite crystal makes it possible to produce third-harmonic with shorter wavelength even in deep UV region. In the experiment, phase-matching angles and phase-mismatching angles of type-II which was the most efficient phase-matching type were measured in calcite crystal and α-BBO crystal. The results may provide a reference for further study on direct third-harmonic generation.
      原文链接:
    • NSTL

    Novel pumping scheme of Holmium doped fiber amplifiers operating around 2μm using 1.48μm lasers exploiting cascaded fiber lasers

    Mirza J.Atieh A.Kanwal B.Ghafoor S....
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHThe optical communication window around 2μm is attracting significant research attention for future optical communication systems as an extension to the C-, L-, and U-bands. One of the research topics in the 2μm region is optical amplifiers. Holmium-doped fiber amplifier (HDFA) is a suitable candidate for amplifying signals in this region. However, the pump laser for Holmium-doped fiber (HDF) is expensive and not widely available. In this work, we propose through numerical simulations, a novel pumping scheme to pump the HDF using commercially available 1.48μm lasers by exploiting cascaded fiber lasers made up of Erbium-doped fiber (EDF) and Thulium-doped fiber (TDF). The first fiber uses a commercially available 1.48μm laser to pump a piece of EDF to generate a 1.62μm continuous wave (CW) laser. This 1.62μm CW laser is used to pump a piece of TDF in the second fiber laser to create a 1.95μm CW laser that is used to pump the HDF. The HDFA can be used to amplify modulated optical signals in the 2μm wavelength range. A small-signal gain of 52.5 dB, 46.2 dB, and 32.6 dB can be achieved for input signal powers of −30 dBm, −15 dBm, and 0 dBm, respectively, at 2.032μm using a 5 W laser diode pump at 1.48μm. A noise figure (NF) of 7.5 dB, 6.6 dB, and 5.58 dB has been observed for input signal power of −30 dBm, −15 dBm, and 0 dBm, respectively at 2.032μm.
      原文链接:
    • NSTL

    A simple model for studying the effects of activation treatment on the defects structure of cadmium telluride solar cells

    Guillermo H.Abelenda A.Rimmaudo I.Lopez-Sanchez A....
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHThis work presents a SCAPS software model based on defect concentration profiles for the CdTe absorber layer in a CdS/CdTe solar cell. It considers three different phenomena which influence the net free carrier concentration (doping, recombination, and compensation), by assigning them a generic defect level. The model has been successfully tested by simulating JV measurements in dark and light of simple CdS/CdTe devices treated with different CdCl2 and CHClF2-treatments and showing different efficiencies. We found that the obtained defect profiles vary with different treatments as expected, and the results are in good agreement with the literature reports. This indicates that the model may be useful as a simple method for studying and optimizing thin-film solar cells.
      原文链接:
    • NSTL

    Analysis of a multi-Fano plasmonic split-ring structure using characteristic mode theory for optical applications

    Gholami A.Ahmadi-Shokouh J.Dashti H.
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHMulti-Fano plasmonic structures are attractive for sensing and energy harvesting due to their ability to adjust resonances at several wavelengths and the high electric field enhancement. In this paper, the Characteristic Mode Theory (CMT) is used to get a multi-Fano structure, for the first time. For this purpose, the results of CMT in the Heptamer consisting of nanorings, are used. It has been shown that modes can resonate and couple together at the same time if the bending frequency of their eigenvalues is between their resonant frequencies (1470 nm for bending, 1382 and 1600 nm for the two modes) which has not been reviewed anywhere before. Then, to create more couplings between the modes and to produce a multi-Fano structure, the modes with coupling ability and their characteristic current distribution are considered. Some gaps have been created in the location of the smallest currents for increasing the coupling and intensifying the electric field (unlike trial and error methods previously used to improve the performance of the structures), and so, two split-ring Heptamer structures are created as multi-Fano structures. It has been shown that the proposed structure has a significant electric field enhancement of |450|2 which is a good choice for energy harvesting. In addition, these structures can be used for sensors with the most sensitivity of 840 nm / RIU, which has a significant sensitivity than similar structures.
      原文链接:
    • NSTL

    A dual-channel microwave photonic mixer with large dynamic range

    Fan Y.Gao Y.Shi F.
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHA microwave photonic mixer has the advantages of large transmission bandwidth, good frequency tunability, high isolation, and anti-electromagnetic interference. For the practical application of the multi-input multi-output (MIMO) communication system, a dual-channel, large dynamic range microwave photonic mixer is proposed in this paper. By controlling the bias angle of the modulator and applying a dual-polarization coherent receiver, the quadrature modulation and demodulation of the dual-channel radio frequency (RF) signal is realized. By constructing a heterodyne polarization light source and adjusting the laser power difference, the third-order intermodulation distortion (IMD3) component in the dual-channel frequency conversion signal can be suppressed. Moreover, due to the balanced detection technology, the second-order spurious-free dynamic range (SFDR2) and the third-order spurious-free dynamic range (SFDR3) of the system are simultaneously improved. Simulation results show that this scheme can obtain local oscillator-radio frequency (LO-RF) isolation of more than 40 dB, SFDR2 of more than 98 dB·Hz1/2, and SFDR3 of more than 115 dB·Hz2/3. In the 16quadrature amplitude modulation (QAM) vector signal test with 450 MHz bandwidth, the adjacent channel power ratio (ACPR) of the system is up to 53 dB and the error vector amplitude (EVM) is as low as 0.3%. Finally, the error analysis of the system is also carried out.
      原文链接:
    • NSTL

    A compact four-peak MIM filter based on asymmetric distribution of resonators

    Fang D.Wang L.Liu C.Zhang J....
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHWe theoretically propose and numerically analyze a compact Metal-Insulator-Metal(MIM) filter based on an asymmetric structure which can produce four peaks in the spectrum. The filter can generate four transmission peaks while the maximum transmission coefficient of each peak is above 90%, and each transmission peak can be individually tuned by changing the coupling angle between the resonators and the waveguide. The structure consists of a pair of asymmetric cavities above and below the waveguide. By adjusting the coupling angle between the cavities and waveguide, each cavity can filter out light of a specific wavelength. The transmittance of the lowest transmission peak could be 3% and each transmission peak has a narrow frequency width. The quality factor (Q) of the resonances are 29.5, 42.9, 17.3 and 77.1, respectively. The sensitivities are 500nm/RIU, 588 nm/RIU, 659 nm/RIU and 827 nm/RIU. The FOMs are 26.3, 39.2, 15.3, 75.2. Multimode interference coupled-mode theory (MICMT) is used for numerical calculation and theoretical analysis. The structure is compact and easy to be fabricated and has potential applications in nano-optical communication.
      原文链接:
    • NSTL

    Investigation of irradiation parameters on fluid flow in microchannels fabricated on polymethyl methacrylate by a KrF laser

    Vesal M.Ghafary B.Mollabashi M.Pazokian H....
    5页
    查看更多>>摘要：© 2022 Elsevier GmbHDue to the increasing importance of microfluidic chips in medical, nuclear, and chemical industries, we focused on improving various parameters in manufacturing their components, most importantly microchannels. Channels with a length of several hundred microns are constructed based on two crucial factors: substrates and the procedure. Numerous substrates can be employed, amongst which PMMA polymer has been chosen due to its transparency, flexibility, and cheapness with respect to glass. As for the procedure, laser ablation is commonly used for manufacturing microchannels. Nanosecond KrF laser is used to advantage from not only its high absorption of polymeric material in ultra-violet wavelengths but also its higher accessibility and cost-effectiveness. In this paper, irradiation parameters are optimized including the scanning speed of the laser, laser fluence, and repetition rate of the laser pulse in the fabrication of microchannels on PMMA polymer. The fluidic properties of the fabricated channels such as hydraulic diameter, Reynolds number, and the regime of water flow are also investigated. Results confirm the domination of the laminar regime for water flow in these microchannels.
      原文链接:
    • NSTL