Journals >Optoelectronics Letters
Contents
2012
Volume: 8 Issue 2
18 Article(s)
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Research Article
Synthesis and characterization of ball milled Fe-doped ZnO diluted magnetic semiconductor
Elilarassi R., and Chrasekaran G.
Fe-doped ZnO (Zn0.99Fe0.01O) powders are successfully prepared by ball milling with different milling time, and are investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet-visible (UV-VIS) spectroscopy, vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR) speFe-doped ZnO (Zn0.99Fe0.01O) powders are successfully prepared by ball milling with different milling time, and are investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet-visible (UV-VIS) spectroscopy, vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR) spectroscopy. The structural analysis using XRD reveals that the Fe-doped ZnO milled at different milling time can crystallize in a wurtzite structure, and in the XRD patterns, the secondary phase related to Fe cluster with the sensitivity of the XRD instrument can not be found. The SEM image of the sample milled for 24 h shows the presence of spherical nanoparticles. From the optical analysis, the optical band gap is found to decrease with increasing the milling time, which indicates the incorporation of Fe2+ ions into the ZnO lattice. The magnetization measurement using VSM reveals that the nanoparticles exhibit ferromagnetic behavior at room temperature, and the magnetization increases gradually with increasing the milling time. The conclusion is further confirmed by the electron paramagnetic resonance of the nanoparticles examined at room temperature, which shows an intense and broad ferromagnetic resonance signal related to Fe ions..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, -1 (2012)
Porous silicon biosensor for detection of variable domain of heavy-chain of HCAb antibody
Hong-yan ZHANG, Xiao-yi LU, Zhen-hong JIA, Jiang-wei LI, and Fu-chun ZHANG
In this paper, we produce porous silicon (PSi) by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain of heavy-chain antibody (VHH). The binding of hen egg white lysozyme (HEWL) and VHH causes a red shift inIn this paper, we produce porous silicon (PSi) by electrochemical etching, and it is the first time to evaluate the performance of label-free porous silicon biosensor for detection of variable domain of heavy chain of heavy-chain antibody (VHH). The binding of hen egg white lysozyme (HEWL) and VHH causes a red shift in the reflection spectrum of the biosensor. The red shift is proportional to the VHH concentration in the range from 14 μg?ml-1 to 30 μg?ml-1 with a detection limit of 0.648 μg?ml-1. The research is useful for the development of label-free biosensor applied in the rapid and sensitive determination of small molecules..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 81 (2012)
Characteristic analysis of a novel F-P interferometer based on a pair of FBGs with built-in LPFGs
Chun-bao WANG, Wei-gang ZHANG, Juan RUAN, Jia-bin SHANG, and Ai-dong YAN
The transmission characteristics of a Fabry-Pérot (F-P) interferometer based on a fiber Bragg grating (FBG) pair with a built-in long-period fiber grating (LPFG) are theoretically analyzed, and the shift of transmission interference fringe as a function of environmental refractive index is acquired. The influence The transmission characteristics of a Fabry-Pérot (F-P) interferometer based on a fiber Bragg grating (FBG) pair with a built-in long-period fiber grating (LPFG) are theoretically analyzed, and the shift of transmission interference fringe as a function of environmental refractive index is acquired. The influence of the lengths of F-P cavity, LPFG and FBG on the transmission characteristics of the proposed interferometer has been numerically investigated, and the simulation results indicate that the sensitivity of refractive index reaches 2.27×10-6 for an optical spectrum analyzer (OSA) with a resolution of 1 pm..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 84 (2012)
All-optical ultra-wideband doublet signal source based on the cross-gain modulation in a semiconductor optical amplifier
Zan-shan ZHAO, Pei-li LI, Jia-jin ZHENG, Ting-ting PAN, Shi-jie HUANG, and You-hong LUO
We propose a novel scheme to generate the ultra-wideband (UWB) doublet signal pulse based on the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). In the scheme, only an optical source and an SOA are needed. As there is only one wavelength included in the output doublet signal pulse, no time diffeWe propose a novel scheme to generate the ultra-wideband (UWB) doublet signal pulse based on the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). In the scheme, only an optical source and an SOA are needed. As there is only one wavelength included in the output doublet signal pulse, no time difference between the upper and down pulses is introduced during the transmission process. By using the software of Optisystem 7.0, the impacts of the optical power, the SOA current, the wavelength and the input signal pulse width on the generated doublet pulse are simulated and tudied numerically. The results show that when the pulse width of the input signal pulse is larger, the output signal pulse is better, and is insensitive to the change of wavelength. In addition, the ultra-wideband positive and negative monocycles can be generated by choosing suitable optical source power and SOA current..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 89 (2012)
Optimization and degradation of rubrene/C70 heterojunction solar cells
Zi-guo CHEN, Peng-yi LIU, Lin-tao HOU, Wen-jie MAI, and Bing WU
Small molecule organic solar cells (OSCs) with the structure of indium tin oxide (ITO)/molybdenum trioxide (MoO3) (5 nm)/rubrene (x nm)/fullerene (C70) (y nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) (6 nm)/aluminum (Al) (150 nm) are fabricated. The thickness of active layer for the devices is investigateSmall molecule organic solar cells (OSCs) with the structure of indium tin oxide (ITO)/molybdenum trioxide (MoO3) (5 nm)/rubrene (x nm)/fullerene (C70) (y nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) (6 nm)/aluminum (Al) (150 nm) are fabricated. The thickness of active layer for the devices is investigated in details. The results show that the optimum thicknesses of rubrene layer and C70 layer are 30 nm and 25 nm, respectively. The degradation of the device is also investigated. The result indicates that the open-circuit voltage (Voc) does not change, while the short-circuit current density (Jsc), fill factor (FF) and power conversion efficiency (PCE) decrease continuously with time. The degradation can be attributed to the oxygen in ambient diffusing and infiltrating into the active materials and reacting with C70 in cells, which can result in the increase of interfacial series resistance..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 93 (2012)
Fabrication and characteristics of low loss and single-mode channel waveguides based on DNA-HCTAC biopolymer material
Fei-yan ZHANG, Zhen-yong WANG, Cheng-en YAN, and Jun ZHOU
A novel biopolymer, deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-HCTAC), is used as the core layer material in optical waveguide, and the cleanroom technology is successfully applied to fabricate the single-mode channel waveguides with low propagation loss. The prepared DNA-HCTAC material shows high oA novel biopolymer, deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-HCTAC), is used as the core layer material in optical waveguide, and the cleanroom technology is successfully applied to fabricate the single-mode channel waveguides with low propagation loss. The prepared DNA-HCTAC material shows high optical quality at the optical telecommunication wavelengths, such as high transparency, relatively high refractive index and low birefringence. In the fabrication approach, polymethyl methacrylate (PMMA) is used as a barrier layer to protect the DNA-HCTAC material from the corrosive of photoresist developer, and the etching conditions are optimized to form the smooth wall and sharp cross-section of the waveguide. Lastly, the optical characteristics of DNA-HCTAC channel waveguides are measured. The results show that the DNA-HCTAC waveguide operates with single-mode propagation and has a low optical loss..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 97 (2012)
Refractive index and temperature dependent displacementsof resonant peaks of long period grating inscribed in hydrogen loaded SMF-28 fiber
Libish T. M., Bobby M. C., Linesh J., Mathew S., Pradeep C., N Nampoori V. P., and Radhakrishnan P.
In this paper, the effects of refractive index (RI) of surrounding medium and ambient temperature on the transmission characteristics of a long period grating (LPG) are experimentally analyzed. The spectral behavior of LPG is investigated when the ambient index is higher or lower than that of the cladding material. TheIn this paper, the effects of refractive index (RI) of surrounding medium and ambient temperature on the transmission characteristics of a long period grating (LPG) are experimentally analyzed. The spectral behavior of LPG is investigated when the ambient index is higher or lower than that of the cladding material. The results show that the refractive index sensitivity of lower order attenuation bands is very low compared with that of the highest order attenuation band. But in the case of temperature, the lower order attenuation bands of the LPG can also exhibit good sensitivity like the higher-order bands..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 101 (2012)
Analysis of false alarm for imaging space-based laser warning system
Hong-jun DONG, Zhong-liang ZHOU, and Fu-yu HUANG
In view of the problem of false alarm in imaging space-based laser warning system, the effects of sunlight and lightning on the threaten laser detection and attack event determination are studied by analyzing and calculating the radiant energy density and space-time feature of imaging spot, respectively. The results shIn view of the problem of false alarm in imaging space-based laser warning system, the effects of sunlight and lightning on the threaten laser detection and attack event determination are studied by analyzing and calculating the radiant energy density and space-time feature of imaging spot, respectively. The results show that the main false alarm resourses of spacebased laser warning system are sunlight and lightning. The sunlight should exposure the detector directly in one ninth of the satillite orbital period, and the imaging spot of sun is similar to the attack laser. The lightning imaging spot is similar to the illumination laser. About 1.4 lightning events can occur in the field of view (FOV) of the warning system per second. It could not discriminate spots of sun, lightning and threaten laser by the frame subtraction technology..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 105 (2012)
Visible photoluminescence from ZnO/diamond-like carbon thin films
Li-chun ZHANG, Qing-shan LI, Yan-feng DONG, and Zi-xia MA
ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD) on Si (111) wafer. Visible room-temperature photoluminescence (PL) is observed from ZnO/DLC thin films by fluorescence spectrophotometer. The Gaussian curve fitting of PL spectra reveals that the broadband visible emission contains ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD) on Si (111) wafer. Visible room-temperature photoluminescence (PL) is observed from ZnO/DLC thin films by fluorescence spectrophotometer. The Gaussian curve fitting of PL spectra reveals that the broadband visible emission contains three components with λ=508 nm, 554 nm and 698 nm. The origin and possible mechanism of the visible PL are discussed, and they can be attributed to the PL recombination of ZnO and DLC thin films..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 113 (2012)
Research on the piezoelectric response of cubic and hexagonal boron nitride films
Xi-ming CHEN, Lian-jie SUN, Bao-he YANG, Yan GUO, and Xiao-guo WU
Boron nitride (BN) films for high-frequency surface acoustic wave (SAW) devices are deposited on Ti/Al/Si(111) wafers by radio frequency (RF) magnetron sputtering. The structure of BN films is investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) spectra, and the surface morphology Boron nitride (BN) films for high-frequency surface acoustic wave (SAW) devices are deposited on Ti/Al/Si(111) wafers by radio frequency (RF) magnetron sputtering. The structure of BN films is investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) spectra, and the surface morphology and piezoelectric properties of BN films are characterized by atomic force microscopy (AFM). The results show that when the flow ratio of nitrogen and argon is 2:18, the cubic BN (c-BN) film is deposited with high purity and c-axis orientation, and when the flow ratio of nitrogen and argon is 4:20, the hexagonal BN (h-BN) film is deposited with high c-axis orientation. Both particles are uniform and compact, and the roughnesses are 1.5 nm and 2.29 nm, respectively. The h-BN films have better piezoelectric response and distribution than the c-BN films..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 117 (2012)
Composite failure prediction of π-joint structures under bending
Hong-mei HUANG, and Shen-fang YUAN
In this article, the composite π-joint is investigated under bending loads. The “L” preform is the critical component regarding composite π-joint failure. The study is presented in the failure detection of a carbon fiber composite π-joint structure under bending loads using fiber Bragg grating (FBG) sensor. Firstly, baIn this article, the composite π-joint is investigated under bending loads. The “L” preform is the critical component regarding composite π-joint failure. The study is presented in the failure detection of a carbon fiber composite π-joint structure under bending loads using fiber Bragg grating (FBG) sensor. Firstly, based on the general finite element method (FEM) software, the 3-D finite element (FE) model of composite π-joint is established, and the failure process and every lamina failure load of composite π-joint are investigated by maximum stress criteria. Then, strain distributions along the length of FBG are extracted, and the reflection spectra of FBG are calculated according to the strain distribution. Finally, to verify the numerical results, a test scheme is performed and the experimental spectra of FBG are recorded. The experimental results indicate that the failure sequence and the corresponding critical loads of failure are consistent with the numerical predictions, and the computational error of failure load is less than 6.4%. Furthermore, it also verifies the feasibility of the damage detection system..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 121 (2012)
Propagation characteristics of six-core photonic liquid crystal fibers
Xiao-qi LIU, Yong-jun LIU, Wei-min SUN, Yu JIANG, Qi YAN, and Hai-jiao YU
We demonstrate a new kind of multi-core photonic liquid crystal fibers (PLCFs) which have six liquid crystal cores arrayed in the ring-type geometry and separated by the air holes. Through analyzing the structure of this kind of PLCFs, it can be found that they have the ability to resist the structure deformation. Due We demonstrate a new kind of multi-core photonic liquid crystal fibers (PLCFs) which have six liquid crystal cores arrayed in the ring-type geometry and separated by the air holes. Through analyzing the structure of this kind of PLCFs, it can be found that they have the ability to resist the structure deformation. Due to the effective index of the liquid crystal can be adjusted by temperature and wavelength, the energy in the six liquid crystal cores is increased with the temperature increasing and wavelength decreasing. The effective index of the PLCFs is decreased, the effective fundamental mode area is increased and the dispersion properties are gently affected with the wavelength increasing and temperature decreasing..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 125 (2012)
A novel orthogonal modulation format of D8PSK/ASK with differential bi-phase encoding and its application in a label switching optical network
Xing ZHANG, Xiao-lei ZHANG, Yong-jun WANG, Xiang-jun XIN, Xiao-li YIN, Ling LI, and Ji-jun ZHAO
The principle of a novel orthogonal modulation format of differential 8-level phase-shift keying amplitude-shift keying (D8PSK/ASK) with differential bi-phase encoding (DBC) is introduced. Based on it, an optical labeling scheme, in which the payload is 100 Gbit/s D8PSK signal and the label is 10 Gbit/s DBC-ASK signal,The principle of a novel orthogonal modulation format of differential 8-level phase-shift keying amplitude-shift keying (D8PSK/ASK) with differential bi-phase encoding (DBC) is introduced. Based on it, an optical labeling scheme, in which the payload is 100 Gbit/s D8PSK signal and the label is 10 Gbit/s DBC-ASK signal, is proposed and simulated. The results are compared with other current schemes, and the effects of transmission range, modulation extinction ratio (ER) and received power on system performance are analyzed, respectively. The results show that the spectrum efficiency and bit error rate (BER) are improved greatly, and when the modulation ER is increased to 11 dB, the balanced performance between the payload and label is achieved..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 129 (2012)
A novel duplex WDM-PON with DPSK modulated downstream and re-modulation of the downlink signal for OOK upstream
Hussain Aftab, Chong-xiu YU, Xiang-jun XIN, Quan-xin YUAN, Bo LIU, Hussain Ashiq, Latif Abdul, Munir Abid, Khan Yousaf, and Afridi Idress
We experimentally demonstrate and analyze a 10 Gbit/s full duplex wavelength division multiplexing passive optical network (WDM-PON) system. A non-return-to-zero differential phase shift keying (NRZ-DPSK) modulation technique is first utilized for downlink direction, and then the downlink signal is re-modulated for theWe experimentally demonstrate and analyze a 10 Gbit/s full duplex wavelength division multiplexing passive optical network (WDM-PON) system. A non-return-to-zero differential phase shift keying (NRZ-DPSK) modulation technique is first utilized for downlink direction, and then the downlink signal is re-modulated for the uplink direction using intensity modulation technique of on-off keying (OOK) with a data rate of 10 Gbit/s per channel. An effective colorless WDM-PON full duplex transmission system is achieved for the data rate of 10 Gbit/s per channel with a channel spacing of 60 GHz over the distance of 25 km with low power penalty..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 134 (2012)
Numerical analysis of intermodal delay in few-mode fibers for mode division multiplexing in optical fiber communication systems
Munir Abid, Xiang-jun XIN, Bo LIU, Latif Abdul, Hussain Aftab, and Niazi Shahab Ahmad
In order to achieve higher spectral efficiency, mode division multiplexing (MDM) in few-mode fibers is a new research area. The idea faces lots of technical issues including intermodal delay and mode coupling which limit the achievable length of the system. This paper is designated to complete the analysis of intermodaIn order to achieve higher spectral efficiency, mode division multiplexing (MDM) in few-mode fibers is a new research area. The idea faces lots of technical issues including intermodal delay and mode coupling which limit the achievable length of the system. This paper is designated to complete the analysis of intermodal delay in step-index few-mode fibers. We analyze numerically all the parameters of fiber, which could impact intermodal delay in few-mode fibers and identify the conditions which can increase the number of multiplex modes without significant increase in maximum intermodal delay..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 138 (2012)
Design and experiment of post-equalization for OOK-NRZ visible light communication system
Shuang-zuo ZHANG, Chuan-tao ZHENG, Yan-ting LI, Wei-lin YE, and Yang LIU
Considering that the white LED’s spectral response decreases exponentially with the increase of carrier frequency for the on-off-keying non-return-to-zero (OOK-NRZ) visible light communication (VLC) data links, a first-order RC high-pass filter is designed and fabricated as a post-equalizer (PE) to compensate the LED sConsidering that the white LED’s spectral response decreases exponentially with the increase of carrier frequency for the on-off-keying non-return-to-zero (OOK-NRZ) visible light communication (VLC) data links, a first-order RC high-pass filter is designed and fabricated as a post-equalizer (PE) to compensate the LED spectral response. Formulation and simulation are both available for illustrating the VLC performance with and without PE. Experiments are performed in detail for the fabricated OOK-NRZ VLC system integrated with PE. The data transmission results show that by using PE, the measured carrier bandwidth is enhanced from 0.8 (0.4-1.2) MHz to 1.7 (0-1.7) MHz, and the bit-error-rate (BER) is less than 10-9. It proves the feasibility of the proposed scheme in OOK-NRZ VLC data links..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 142 (2012)
A rotating inertial navigation system with the rotating axis error compensation consisting of fiber optic gyros
Feng ZHA, Bai-qing HU, Fang-jun QIN, and Yin-bo LUO
An effective and flexible rotation and compensation scheme is designed to improve the accuracy of rotating inertial navigation system (RINS). The accuracy of single-axial RINS is limited by the errors on the rotating axis. A novel inertial measurement unit (IMU) scheme with error compensation for the rotating axis of fAn effective and flexible rotation and compensation scheme is designed to improve the accuracy of rotating inertial navigation system (RINS). The accuracy of single-axial RINS is limited by the errors on the rotating axis. A novel inertial measurement unit (IMU) scheme with error compensation for the rotating axis of fiber optic gyros (FOG) RINS is presented. In the scheme, two couples of inertial sensors with similar error characteristics are mounted oppositely on the rotating axes to compensate the sensors error. Without any change for the rotation cycle, this scheme improves the system’s precision and reliability, and also offers the redundancy for the system. The results of 36 h navigation simulation prove that the accuracy of the system is improved notably compared with normal strapdown INS, besides the heading accuracy is increased by 3 times compared with single-axial RINS, and the position accuracy is improved by 1 order of magnitude..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 146 (2012)
Generation of four-photon GHZ states based on interaction between a four-level atom and two bimodal cavities
Deng-yu ZHANG, Shi-qing TANG, Xin-wen WANG, Li-jun XIE, Xiao-gui ZHAN, and Yin-hua CHEN
A simple scheme is presented for generating four-photon Greenberger-Horne-Zeilinger (GHZ) states with interaction between a four-level atom and two bimodal cavities. In the proposed protocol, the quantum information is encoded on Fock states of the cavity fields. The detection of the atom can collapse the cavity to theA simple scheme is presented for generating four-photon Greenberger-Horne-Zeilinger (GHZ) states with interaction between a four-level atom and two bimodal cavities. In the proposed protocol, the quantum information is encoded on Fock states of the cavity fields. The detection of the atom can collapse the cavity to the desired state. The experimental feasibility of our proposal is also discussed..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 2, 150 (2012)
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