Journals >Optoelectronics Letters
Contents
2012
Volume: 8 Issue 4
20 Article(s)
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Research Article
Synthesis and photoluminescent properties of ZnO:Cu/ZnO core/shell nanocrystals
Mei-hui LI, Xi-ming CHEN, Jian-ping XU, Xiao-song ZHANG, Yan-yu WU, Ping LI, Xi-ping NIU, Cheng-yuan LUO, and Lan LI
ZnO:Cu/ZnO core/shell nanocrystals are synthesized by a two-step solution-phase process. The morphology, structure and optical properties of the samples are detected by scanning electron microscopy, Raman, absorption and luminescence spectroscopy. The increase of particle size confirms the growth of ZnO shell. The segrZnO:Cu/ZnO core/shell nanocrystals are synthesized by a two-step solution-phase process. The morphology, structure and optical properties of the samples are detected by scanning electron microscopy, Raman, absorption and luminescence spectroscopy. The increase of particle size confirms the growth of ZnO shell. The segregation of CuO phase observed in ZnO: Cu core is not detected in ZnO:Cu/ZnO core/shell nanocrystals from Raman spectra. It is suggested that some Cu ions can be segregated from ZnO nanocrystals, and the separated Cu ions can be incorporated inside ZnO shell after the growth of ZnO shell. The visible emission mechanism is discussed in detail, and the photoluminescence analysis indicates that the core/shell structure helps to eliminate the surface-related emission..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 241 (2012)
Theoretical and experimental researches on a PCF-based SPR sensor
Pi-bin BING, Zhong-yang LI, Jian-quan YAO, Ying LU, Zhi-gang DI, and Xin YAN
A photonic crystal fiber based surface plasmon resonance (PCF-SPR) sensor is simulated by finite element method and experimentally realized. The calculations show that there is an obvious loss peak in the vicinity of 1.2 μm while the PCF of LMA-8 is used as a sensor. The suspension of silver nanoparticle mixed with hexA photonic crystal fiber based surface plasmon resonance (PCF-SPR) sensor is simulated by finite element method and experimentally realized. The calculations show that there is an obvious loss peak in the vicinity of 1.2 μm while the PCF of LMA-8 is used as a sensor. The suspension of silver nanoparticle mixed with hexadecyl trimethyl ammonium bromide (CTAB) is inhaled into the PCF to form a metal film which can be stimulated to generate plasmon in the experiment. A spectrometer is utilized to detect the continuous broadband transmission spectrum from the PCF. The experimental results verify the loss peak. Compared with the theoretical calculations, the offset of loss peak about 40 nm can be acceptable, because the uniformity of the metal coating is difficult to guarantee and the film thickness is difficult to control..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 245 (2012)
Design and simulation of a novel CMOS superimposed photodetector
Yu-zhuo KANG, Lu-hong MAO, Xin-dong XIAO, Sheng XIE, and Shi-lin ZHANG
A novel superimposed photodetector (PD) is put forward. The photodetector can obtain a couple of differential photocurrent signals from one input optical signal. The light injection efficiency and the vertical work distance of this new photodetector are much higher than those of the others. The superimposed photodetctoA novel superimposed photodetector (PD) is put forward. The photodetector can obtain a couple of differential photocurrent signals from one input optical signal. The light injection efficiency and the vertical work distance of this new photodetector are much higher than those of the others. The superimposed photodetctor is designed based on the standard 0.18 μm CMOS process. The responsivity, bandwidth and transient response of the photodetector are simulated by a commercial simulation software of ATLAS. The responsivities of two obtained photocurrent signals are 0.035 A/W and 0.034 A/W, while the bandwidths are 3.8 GHz and 5.2 GHz, respectively. A full differential optical receiver which uses the superimposed photodetector as input is simulated. The frequency response and 4 Gbit/s eye diagram of the optical receiver are also obtained. The results show that the two output signals can be used as the differential signal..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 249 (2012)
Ultra-small microring resonator based on sub-micrometer fiber
Xiao-wei DONG, and Wen-kai LIU
The transfer function of the microring resonator is deduced, and the effects of the normalized loss, coupling coefficient and surrounding media on the resonance performance are investigated thoroughly. Utilizing the improved fused tapering technique and ingenious self-coiling coupling method, a high-quality microring rThe transfer function of the microring resonator is deduced, and the effects of the normalized loss, coupling coefficient and surrounding media on the resonance performance are investigated thoroughly. Utilizing the improved fused tapering technique and ingenious self-coiling coupling method, a high-quality microring resonator (radius of about 500 μm) with larger extinction ratio (>10 dB) and sharper resonance is designed and fabricated by a segment of continuous sub-micrometer fiber. The microring resonator constructed in this way demonstrates extremely small connection loss with communication fiber in contrast to the planar waveguide technology..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 253 (2012)
MoO3 as a cathode buffer layer for enhancing the efficiency in white organic light-emitting diodes
Jing ZHANG, Fang-hui ZHANG, Lei DING, Yan-fei LI, and Tian-jing LIANG
Molybdenum trioxide (MoO3) as a cathode buffer layer is inserted between LiF and Al to improve the efficiency of white organic light-emitting diodes (OLEDs) in this paper. By changing the MoO3 thickness, a higher current efficiency of 5.79 cd/A is obtained at a current density of 160 mA/cm2 for the device with a 0.8 nmMolybdenum trioxide (MoO3) as a cathode buffer layer is inserted between LiF and Al to improve the efficiency of white organic light-emitting diodes (OLEDs) in this paper. By changing the MoO3 thickness, a higher current efficiency of 5.79 cd/A is obtained at a current density of 160 mA/cm2 for the device with a 0.8 nm-thick MoO3 layer as the cathode buffer layer, which is approximately two times greater than that of the device without MoO3. The mechanism for improving the device efficiency is discussed. Moreover, at a voltage of 13 V, the device with a 0.8 nm-thick MoO3 layer achieves a higher luminance of 22370 cd/m2, and the Commission Internationale de I,Eclairage (CIE) color coordinate of the device with 1 nm-thick MoO3 layer is (0.33, 0.34), which shows the best color purity. Simple electron-only devices are tested to confirm the impact of the MoO3 layer on the carrier injection..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 256 (2012)
Research of organic field effect transistors based on semiconducting single-walled carbon nanotubes
Xiao-yan YANG, Xiao-ming WU, Chun-xia JIANG, Xue-song HAN, Zhi-qi GAO, Li-ying SHEN, Jun WEI, and Shou-gen YIN
The metal-conducting single-walled carbon nanotubes (m-SWNTs) with small diameters (0.7 nm-1.1 nm) are selectively removed from the single-walled carbon nanotubes (SWNTs) by using HNO3/H2SO4 mixed solution. Semiconducting singlewalled carbon nanotubes (s-SWNTs) can be separated efficiently from the SWNTs with high contThe metal-conducting single-walled carbon nanotubes (m-SWNTs) with small diameters (0.7 nm-1.1 nm) are selectively removed from the single-walled carbon nanotubes (SWNTs) by using HNO3/H2SO4 mixed solution. Semiconducting singlewalled carbon nanotubes (s-SWNTs) can be separated efficiently from the SWNTs with high controllability and purity based on this novel method, and the outcome is characterized by Raman spectrum. Moreover, the organic field effect transistors (OFETs) are fabricated based on the poly (3-hexylthiophene-2, 5-diyl) (P3HT), and untreated SWNTs and separated SWNTs (s-SWNTs) are mixed with P3HT, respectively. It could be found that the P3HT/s-SWNT device exhibits a better field effect characteristic compared with the P3HT device. The current on/off ratio is increased by 4 times, the threshold voltage is also increased from -28 V to -22 V, and the mobility is increased from 3×10-3 cm2/Vs to 5×10-3cm2/Vs..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 260 (2012)
Reflective terahertz tunable polarization controller
Chao NIU, and Sheng-jiang CHANG
This paper proposes an optical device which can continuously change the polarization state of terahertz (THz) waves. The device consists of metal gate, anti-reflection coatings, liquid crystal and mirror. By changing the refractive index of liquid crystal in the interface between the metal gate and the mirror, the phasThis paper proposes an optical device which can continuously change the polarization state of terahertz (THz) waves. The device consists of metal gate, anti-reflection coatings, liquid crystal and mirror. By changing the refractive index of liquid crystal in the interface between the metal gate and the mirror, the phase difference between two beams with orthogonal polarization is varied and a continuous phase shift is achieved. The phase shift of the device is calculated by using the finite difference time domain (FDTD) method, and the transmittance and reflectance are calculated by using the rigorous coupled wave analysis (RCWA) method. The results reveal that the structure can realize continuously tunable phase shift for THz wave at 1 THz..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 264 (2012)
Design of high-sensitivity metal-coated LPFG sensor based on material dispersion
Yan-jun SHI, and Zheng-tian GU
A high-sensitivity metal-coated long-period fiber grating (LPFG) sensor based on material dispersion is designed. Based on the coupled mode theory, the influence of the material dispersion on the dual-peak characteristics of the metal-coated LPFG is studied. After considering the material dispersion, the jumping regionA high-sensitivity metal-coated long-period fiber grating (LPFG) sensor based on material dispersion is designed. Based on the coupled mode theory, the influence of the material dispersion on the dual-peak characteristics of the metal-coated LPFG is studied. After considering the material dispersion, the jumping region of the dual-resonant-wavelength shifts toward the thinner film thickness, and the sensitivity of the dual-peak metal-coated LPFG sensor to liquid refractive index (RI) can be obtained to supply accurate parameter combinations. Experimentally, two kinds of silver-coated LPFGs with different film thicknesses and grating periods are fabricated to monitor the salt solution, and the sensitivities of these two sensors are compared. The experimental results are consistent with the theoretical analyses..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 269 (2012)
Concentration-dependent luminescence properties in Er3+- doped TeO2- ZnO-La2O3 glasses
Ya-xun ZHOU, Xing-chen XU, Fen CHEN, Jian-hui LIN, and Gaobo YANG
Erbium-doped tellurite-based glasses (Er3+:TeO2-ZnO-La2O3) are prepared by the conventional melt-quenching technique, and concentration-dependent luminescence properties of Er3+ are investigated. A significant spectral broadening of the 1.53 μm fluorescence corresponding to 4I13/2 →4I15/2 transition is observed, and thErbium-doped tellurite-based glasses (Er3+:TeO2-ZnO-La2O3) are prepared by the conventional melt-quenching technique, and concentration-dependent luminescence properties of Er3+ are investigated. A significant spectral broadening of the 1.53 μm fluorescence corresponding to 4I13/2 →4I15/2 transition is observed, and the fluorescence decaying becomes a nearly exponential way with the increasing Er3+ concentration. Radiation trapping is evoked to explain the broadening of 4I13/2 →4I15/2 emission line of Er3+ ions. The optimum doping content of Er2O3 for 1.53 μm fluorescence emission is about 1.5 mol%..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 273 (2012)
Dependence of transmission spectra on director orientation in the photonic crystal with a liquid crystal layer
Li-tao SONG, Jie HE, Hua-lei WANG, Yiang HAN, and Tao LI
The transmission spectra of one-dimensional (1D) photonic crystals (PCs) with parallel and twisted nematic liquid crystals (LCs) as defect layers are discussed by 4 × 4 matrix method, respectively. The results show that the photonic band gap (PBG) mainly depends on the periodic arrays of dielectric composites. TheThe transmission spectra of one-dimensional (1D) photonic crystals (PCs) with parallel and twisted nematic liquid crystals (LCs) as defect layers are discussed by 4 × 4 matrix method, respectively. The results show that the photonic band gap (PBG) mainly depends on the periodic arrays of dielectric composites. The orientation of director and the symmetry of the director configuration have important influence on the location and amplitude of defect modes. The location and amplitude of defect modes can be controlled conveniently by changing the orientation of director. The symmetry of the director configuration can help us understand the defect modes spectra..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 277 (2012)
Loss characteristics of helical-core fiber
Hui-si WANG, Chun-ying GUAN, Di GAO, Jin-hui SHI, and Li-bo YUAN
A special optical fiber is investigated, which has a helical core in the cylindrical cladding. The beam propagation method (BPM) is used for analyzing the impacts of the geometric and physical parameters on the properties of mode losses of the helical-core fiber. The propagation loss is 0.32 dB/m for the fundamental moA special optical fiber is investigated, which has a helical core in the cylindrical cladding. The beam propagation method (BPM) is used for analyzing the impacts of the geometric and physical parameters on the properties of mode losses of the helical-core fiber. The propagation loss is 0.32 dB/m for the fundamental mode and the propagation loss is 20.95 dB/m for the LP11 mode in the wavelength range of 1050-1065 nm when the core diameter is 19 μm, the pitch of the core’s helix is 2.66 mm, and the offset of the helix core from the center of the fiber axis is 31 μm. The core diameter of the single-mode helical-core fiber well exceeds that of the conventional large-mode-area fiber. The helical-core fiber can provide the effective large-mode-area single-mode operation without coiling fiber or selecting excitation mode..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 280 (2012)
A novel RS BTC coding scheme for optical communications
Jian-guo YUAN, Yue-xing JIA, and Yun-xia HU
Tianjin University of Technology and Springer-Verlag Berlin Heidelberg 2012 A novel Reed Solomon (RS) block turbo code (BTC) coding scheme of RS(63,58)×RS(63,58) for optical communications is proposed. The simulation results show that the net coding gain (NCG) of this scheme at the sixth iteration is more than thaTianjin University of Technology and Springer-Verlag Berlin Heidelberg 2012 A novel Reed Solomon (RS) block turbo code (BTC) coding scheme of RS(63,58)×RS(63,58) for optical communications is proposed. The simulation results show that the net coding gain (NCG) of this scheme at the sixth iteration is more than that of other coding schemes at the third iteration for the bit error rate (BER) of 10-12. Furthermore, the novel RS BTC has shorter component code and rapider encoding and decoding speed. Therefore, the novel RS BTC coding scheme can be better used in high-speed long-haul optical communication systems, and the novel RS BTC can be regarded as a candidate code of the super forward error correction (super-FEC) code. Moreover, the encoding/decoding design and implementation of the novel RS BTC are also presented..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 284 (2012)
Wavelength conversion based on nonlinear polarization rotation in gain transparent SOA
Rong-she1 DOU, Chong-xiu1 YU, Kui-ru WANG, Yong-jun WANG, Xin-zhu SANG, Qi ZHANG, and Bin-bin YAN
We describe an all-optical wavelength conversion scheme for 1310 nm to 1550 nm based on nonlinear polarization rotation in a gain-transparent semiconductor optical amplifier (GT-SOA) which brings in the assistant light to improve the property of the converted light. From the SOA carrier density equations, the 1310 nm-tWe describe an all-optical wavelength conversion scheme for 1310 nm to 1550 nm based on nonlinear polarization rotation in a gain-transparent semiconductor optical amplifier (GT-SOA) which brings in the assistant light to improve the property of the converted light. From the SOA carrier density equations, the 1310 nm-to-1550 nm wavelength conversion scheme is analyzed by the Jones matrix. The phase shift between TE and TM modes and the converted light are simulated at bit rate of 30 Gbit/s. We also analyze the influence of the input signal power, the injected current and the assistant light power on the extinction ratio of the converted light..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 289 (2012)
A millimeter-wave radio-over-fiber system for overcoming fiber dispersion-induced signal cancellation effect
Chattopadhyay Taraprasad
Millimeter-wave (mm-wave) radio over fiber (ROF) using dispersive single-mode fiber is susceptible to signal cancellation effect at the output of the uni-travelling carrier photodiode at the base station (BS). The fiber dispersion effect produces different phase shifts of the sidebands of the intensity-modulated lightwMillimeter-wave (mm-wave) radio over fiber (ROF) using dispersive single-mode fiber is susceptible to signal cancellation effect at the output of the uni-travelling carrier photodiode at the base station (BS). The fiber dispersion effect produces different phase shifts of the sidebands of the intensity-modulated lightwave which can produce a cancellation of the output signal when mixed with the optical carrier. In this paper, we propose and analyze a novel scheme of mm-wave ROF which uses microwave modulation at the central station (CS) and frequency upconversion before the BSs. This scheme can overcome fiber dispersion-induced signal cancellation effect..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 293 (2012)
Suppression of fluctuation on the angle of arrival for freespace optical communication
Ming LI, Song LIN, Shu-ming LI, and Shao-wen YANG
In order to increase the coupling efficiency and suppress the random angular jitter induced by atmosphere turbulent, the fine tracking system with fast steering mirror (FSM) is demonstrated. The field experiment results of free-space optical communication link across 16 km show that when there is no tracking, the rangeIn order to increase the coupling efficiency and suppress the random angular jitter induced by atmosphere turbulent, the fine tracking system with fast steering mirror (FSM) is demonstrated. The field experiment results of free-space optical communication link across 16 km show that when there is no tracking, the range of the x-axis coordinates’ fluctuation achieves 46 pixels, corresponding to the incident angle of 73.6 μrad, and its mean square deviation is 6.5 pixels, corresponding to the incident angle of 10.4 μrad. When there is tracking, the range of fluctuation is suppressed to 10 pixels and 16 μrad, and the mean square deviation reduces to 1.5 pixels and 2.6 μrad for the spot’s centroid and the incident angle, respectively. Significantly, the coupling efficiency increases by 6 times, and the fluctuation of received light power decreases obviously..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 297 (2012)
Influence of phase shift drift and splitting ratio on 80 GHz optical mm-wave generation
Zi-hang ZHU, Shang-hong ZHAO, Zhou-shi YAO, Qing-gui TAN, Yong-jun LI, Yi DONG, and Wei-hu ZHAO
For the scheme of 80 GHz optical millimeter-wave (mm-wave) generation using two cascaded Mach-Zehnder modulators (MZMs), an exact analytical solution for the optical mm-wave affected by phase shift drift and splitting ratio is derived with the method of expanding Bessel series. The results show that for the carrier andFor the scheme of 80 GHz optical millimeter-wave (mm-wave) generation using two cascaded Mach-Zehnder modulators (MZMs), an exact analytical solution for the optical mm-wave affected by phase shift drift and splitting ratio is derived with the method of expanding Bessel series. The results show that for the carrier and the fourth-order sideband, the influence caused by phase shift drift is dominant, while the first-order, the second-order and the third-order sidebands are influenced by both phase shift drift and splitting ratio. It follows that the undesired sideband suppression ratio is at least 35.9 dB when the splitting ratio deviation is 0.001, and the phase shift drift is 1o. The performance of the system is perfect if the accuracy is achieved..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 301 (2012)
SPC-APPM coded modulation for deep-space optical communications
Jian-zhong GUO, Guan-feng QIN, and Lei ZENG
A coded modulation scheme for deep-space optical communications is proposed, which is composed of an outer singleparity- check (SPC)-based product code, an interleaver, a bit-accumulator and a pulse-position modulation (PPM). It is referred as SPC-APPM code, which is decoded with an iterative demodulator-decoder using A coded modulation scheme for deep-space optical communications is proposed, which is composed of an outer singleparity- check (SPC)-based product code, an interleaver, a bit-accumulator and a pulse-position modulation (PPM). It is referred as SPC-APPM code, which is decoded with an iterative demodulator-decoder using standard turbo-decoding techniques. Investigations show that the scheme has the advantages of low encoding and decoding complexities, good performance and flexible code rate for all rates above 1/2. Meanwhile, simulation results demonstrate that the SPC-APPM provides the performance similar to the low-density parity-check-APPM (LDPC-APPM), superior to the LDPC-PPM and product accumulate code-PPM (PA-PPM), although inferior to serially concatenated PPM (SCPPM). At the bit error rate (BER) of 10-5, the performance of SPC-APPM is about 0.7 dB better than LDPC-PPM and 1.2 dB better than PA-PPM..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 306 (2012)
Attenuation of terahertz transmission through rain
Yi LUO, Wan-xia HUANG, and Zi-yi LUO
Based on the Marshall-Palmer, Weibull raindrop size distribution and Mie electromagnetic scattering model, the relationships of attenuation coefficient of terahertz (THz) atmospheric window waves with precipitation rate and temperature are studied. Furthermore, combined with the loss of electromagnetic wave transmissioBased on the Marshall-Palmer, Weibull raindrop size distribution and Mie electromagnetic scattering model, the relationships of attenuation coefficient of terahertz (THz) atmospheric window waves with precipitation rate and temperature are studied. Furthermore, combined with the loss of electromagnetic wave transmission in free space, the attenuation of THz communication and the transmission of current mobile communication signals through rain are compared and analyzed. The results show that the attenuation coefficient of THz transmission is increased with increasing precipitation rate, the difference of attenuation coefficient at different THz window waves is small, and the maximum difference is about 3 dB. The rain attenuation of THz wave is first decreased and then increased with increasing temperature, but the temperature has little effect on it. The attenuation of THz wave through rain is much larger than that of mobile communication signal..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 310 (2012)
Label-free quantitative detection using porous silicon as optical biosensor
Fu-ru ZHONG, Xiao-lin MA, Xiao-yi Lü, and Zhen-hong JIA
The single-layer porous silicon is prepared by electrochemistry etching method, which is used as an immunosensor for determining recombinant mouse zona pellucida 3 fusion protein (r-mZP3) by Raman spectroscopy analysis at room temperature. The molecule binding increases the effective optical thickness (EOT), and thus tThe single-layer porous silicon is prepared by electrochemistry etching method, which is used as an immunosensor for determining recombinant mouse zona pellucida 3 fusion protein (r-mZP3) by Raman spectroscopy analysis at room temperature. The molecule binding increases the effective optical thickness (EOT), and thus the Raman spectrum intensity decreases. The concentration and variation of Raman intensity show a good linear quantitative relation. The excellent sensing performance could open the way to a new family of optical sensors for biological standardization..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 314 (2012)
A simple control system of quantum key distribution with high visibility
Hai-qiang MA, Long WANG, Shen LI, Rong-zhen JIAO, and Lingan WU
A relatively simple plug-and-play control system of quantum key distribution (QKD) based on PCI7300 card is demonstrated, including mechanism design, key generation and key acquisition. The system works very well at the repetition frequency of 1 MHz, and the key generation rate is 100 k/s. A visibility of better than 9A relatively simple plug-and-play control system of quantum key distribution (QKD) based on PCI7300 card is demonstrated, including mechanism design, key generation and key acquisition. The system works very well at the repetition frequency of 1 MHz, and the key generation rate is 100 k/s. A visibility of better than 95% over 50 km-long fiber at 1.31 ??m is obtained, which is stable under ordinary lab conditions for 24 h without any feedback control or adjustment. The presented system is a quite promising candidate to realize the QKD in the future..
Optoelectronics Letters
- Publication Date: Jan. 01, 1900
- Vol. 8, Issue 4, 318 (2012)
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