Volume 3,Issue 1,2007 Table of Contents
2007, 3(1).
Abstract:
This paper reports an investigation on the electrical properties of thin film devices made by Copper(Ⅱ) phthalocyanine derivative and polycarbonate (PC) composite. The conducting and injection mechanism are further discussed. Materials of a variety composition were prepared into the thin film via spin-coating. ITO and aluminum were used as the bottom and top electrode respectively. J-V characteristic was measured and the result demonstrates that at a small bias region an Ohmic contact was achieved. As the forward bias increased,the current became space charge limited. The result of AC impedance measurement indicates the device could be equivalent to a parallel RC system. The introduction of PC into the CuPc possibly reduces the charge overlapping between the aromatic rings and led to a reduction in the molecular interaction.Hence,the ac conductivity decreases sharply as PC composition increases. But no change in the transport mechanism is found.
This paper reports an investigation on the electrical properties of thin film devices made by Copper(Ⅱ) phthalocyanine derivative and polycarbonate (PC) composite. The conducting and injection mechanism are further discussed. Materials of a variety composition were prepared into the thin film via spin-coating. ITO and aluminum were used as the bottom and top electrode respectively. J-V characteristic was measured and the result demonstrates that at a small bias region an Ohmic contact was achieved. As the forward bias increased,the current became space charge limited. The result of AC impedance measurement indicates the device could be equivalent to a parallel RC system. The introduction of PC into the CuPc possibly reduces the charge overlapping between the aromatic rings and led to a reduction in the molecular interaction.Hence,the ac conductivity decreases sharply as PC composition increases. But no change in the transport mechanism is found.
2007, 3(1).
Abstract:
A novel second-order nonlinear optical chromophore (DCDHF-2-V) was synthesized from 3-Hydroxy-3-methyl-2-butanae,propanedinitrile and 4-diethylaminobenzaldehyde by aldol condensation reaction. Molecular structural characterization was investigated by elemental analysis,FTIR,and 1H-NMR spectra. The melting point obtained from DSC thermogram was almost 251 ℃,and the compound shows a thermal stability up to 270 ℃. Second-order NLO properties of the chromophore were measured by solvatochromic method. From the quantum-mechanical two-level model,it can be obtained that the μgβ value of DCDHF-2-V is 6520 × 10-48 esu atthe wavelength of 1064 nm.
A novel second-order nonlinear optical chromophore (DCDHF-2-V) was synthesized from 3-Hydroxy-3-methyl-2-butanae,propanedinitrile and 4-diethylaminobenzaldehyde by aldol condensation reaction. Molecular structural characterization was investigated by elemental analysis,FTIR,and 1H-NMR spectra. The melting point obtained from DSC thermogram was almost 251 ℃,and the compound shows a thermal stability up to 270 ℃. Second-order NLO properties of the chromophore were measured by solvatochromic method. From the quantum-mechanical two-level model,it can be obtained that the μgβ value of DCDHF-2-V is 6520 × 10-48 esu atthe wavelength of 1064 nm.
2007, 3(1).
Abstract:
An 800 nm band fiber Bragg grating sensing interrogation system using tilted FBG as the core wavelength division component is presented. A charge coupled device (CCD) linear array is put on the focal plane of the lens to detect the light. TFBG is used to tap light out of the fiber core to fiber cladding. The sensing wavelength is 795 to 830 nm,with accuracy of 20 pm and scan speed 100 Hz. Using FBG sensor,we achieve the temperature sensitivity of 1.8 ℃ and strain sensitivity of 18 με.
An 800 nm band fiber Bragg grating sensing interrogation system using tilted FBG as the core wavelength division component is presented. A charge coupled device (CCD) linear array is put on the focal plane of the lens to detect the light. TFBG is used to tap light out of the fiber core to fiber cladding. The sensing wavelength is 795 to 830 nm,with accuracy of 20 pm and scan speed 100 Hz. Using FBG sensor,we achieve the temperature sensitivity of 1.8 ℃ and strain sensitivity of 18 με.
Nan-hui Niu
,
Huai-bing Wang
,
Jian-ping Liu
,
Nai-xin Liu
,
Yan-hui Xing
,
Jun Han
,
Jun Deng
,
Guang-di Shen
2007, 3(1):1-3.
Abstract:
InGaN/GaN MQWs structures were grown by MOCVD. The effects of the growth interruption time on the optical and structural properties of InGaN/GaN MQWs were investigated. The experimental results show that the growth interruption can improve the interface quality,increase the intensity of photoluminescence (PL) and electroluminescence (EL); but if the interruption time was too long,the well thickness and the average In composition of MQWs decreased,and the EL intensity also decreased due to poor interface quality and impurities derived from growth interruption.
InGaN/GaN MQWs structures were grown by MOCVD. The effects of the growth interruption time on the optical and structural properties of InGaN/GaN MQWs were investigated. The experimental results show that the growth interruption can improve the interface quality,increase the intensity of photoluminescence (PL) and electroluminescence (EL); but if the interruption time was too long,the well thickness and the average In composition of MQWs decreased,and the EL intensity also decreased due to poor interface quality and impurities derived from growth interruption.
2007, 3(1):4-6.
Abstract:
To implement high quality tunneling injection quantum dot lasers,effects of primary factors on performance of the tunneling injection quantum dot lasers were investigated. The considered factors were tunneling probability,tunneling time and carriers thermal escape time from the quantum well. The calculation results show that with increasing of the ground-state energy level in quantum well,the tunneling probability increases and the tunneling time decreases,while the thermal escape time decreases because the ground-state energy levelis shallower. Longitudinal optical phonon-assisted tunneling can be an effective method to solve the problem that both the tunneling time and the thermal escape time decrease simultaneously with the ground-state energy level increasing in quantum well.
To implement high quality tunneling injection quantum dot lasers,effects of primary factors on performance of the tunneling injection quantum dot lasers were investigated. The considered factors were tunneling probability,tunneling time and carriers thermal escape time from the quantum well. The calculation results show that with increasing of the ground-state energy level in quantum well,the tunneling probability increases and the tunneling time decreases,while the thermal escape time decreases because the ground-state energy levelis shallower. Longitudinal optical phonon-assisted tunneling can be an effective method to solve the problem that both the tunneling time and the thermal escape time decrease simultaneously with the ground-state energy level increasing in quantum well.
2007, 3(1):7-9.
Abstract:
The large refractive index difference between Si and SiO2 makes it possible to realize ultrasmall photonic integrated circuits. A 5×5 ultracompact arrayed waveguide grating multiplexer based on 500×250 nm Si nanowire waveguides is designed and fabricated by using the technologies of E-beam writing and amorphous-Si deposition. The measured channel spacing is about 1.5 nm (close to the design value) and the channel crosstalk is about -8 dB.
The large refractive index difference between Si and SiO2 makes it possible to realize ultrasmall photonic integrated circuits. A 5×5 ultracompact arrayed waveguide grating multiplexer based on 500×250 nm Si nanowire waveguides is designed and fabricated by using the technologies of E-beam writing and amorphous-Si deposition. The measured channel spacing is about 1.5 nm (close to the design value) and the channel crosstalk is about -8 dB.
2007, 3(1):10-13.
Abstract:
A new type of Bragg fibers,i.e. hollow-core cobweb-structured optical fibers,which can be used to the low-loss transmission from visible to near infrared region (0.65 μm-1.55 μm),terahertz wave (200 μm-480 μm) and circular-polarization-maintaining single-mode transmission are investigated. Results show that the hollow-core cobweb-structured fibers have less loss than other hollow-core Bragg fibers. The fibers can be constituted by using the plastics or glasses with large absorption losses.
A new type of Bragg fibers,i.e. hollow-core cobweb-structured optical fibers,which can be used to the low-loss transmission from visible to near infrared region (0.65 μm-1.55 μm),terahertz wave (200 μm-480 μm) and circular-polarization-maintaining single-mode transmission are investigated. Results show that the hollow-core cobweb-structured fibers have less loss than other hollow-core Bragg fibers. The fibers can be constituted by using the plastics or glasses with large absorption losses.
2007, 3(1):14-17.
Abstract:
Based on the character of semiconductors and the structure of optical fiber coupler,a new amplifying fiber,coupled semiconductor quantum dot amplifying fiber (CSQDAF),has been presented. A simplified model of PbS quantum dot amplifying fiber is built on the energy band structure of semiconductor quantum dots,and a simple expression deduced from the two-level rate equations and light propagation equations is shown in this paper,by which the gain of quantum dot amplifying fiber can be calculated. A gain of approximately 4.5 dB has been measured in this coupled semiconductor quantum dot amplifying fiber at a wavelength of 1310 nm,when the fiber is pumped by a laser operating at a wavelength of 980 nm with power of 30 mW.
Based on the character of semiconductors and the structure of optical fiber coupler,a new amplifying fiber,coupled semiconductor quantum dot amplifying fiber (CSQDAF),has been presented. A simplified model of PbS quantum dot amplifying fiber is built on the energy band structure of semiconductor quantum dots,and a simple expression deduced from the two-level rate equations and light propagation equations is shown in this paper,by which the gain of quantum dot amplifying fiber can be calculated. A gain of approximately 4.5 dB has been measured in this coupled semiconductor quantum dot amplifying fiber at a wavelength of 1310 nm,when the fiber is pumped by a laser operating at a wavelength of 980 nm with power of 30 mW.
9 Investigation of all-optical regeneration based on self-phase modulation in microstructured fibers
2007, 3(1):18-21.
Abstract:
All-optical regeneration based on self-phase modulation in microstructured fibers is studied. The effects of pulse peak power into the fiber,pulse width and filter parameters on the performance of the regenerator are investigated. The effects of normal dispersion and anomalous dispersion of the microstructured fiber on optical regeneration are compared. The numerical results show that optical regeneration can be achieved by using microstructured fibers with normal dispersion or anomalous dispersion,but the normal dispersion decreases the oscillatory structure in the broadened spectra and obtain a better regenerator transfer function. In order to achieve optical regeneration,the input peak power into the microstructured fiber and the filter parameters need to meet certain requirements. By optimizing those parameters,a better regeneration result can be obtained.
All-optical regeneration based on self-phase modulation in microstructured fibers is studied. The effects of pulse peak power into the fiber,pulse width and filter parameters on the performance of the regenerator are investigated. The effects of normal dispersion and anomalous dispersion of the microstructured fiber on optical regeneration are compared. The numerical results show that optical regeneration can be achieved by using microstructured fibers with normal dispersion or anomalous dispersion,but the normal dispersion decreases the oscillatory structure in the broadened spectra and obtain a better regenerator transfer function. In order to achieve optical regeneration,the input peak power into the microstructured fiber and the filter parameters need to meet certain requirements. By optimizing those parameters,a better regeneration result can be obtained.
10 Transmission spectrum method to measure the photonic bandgap of hollow-core photonic crystal fiber
2007, 3(1):22-24.
Abstract:
A full-vector plane-wave method is introduced,particularly in calculating the photonic crystal in-plane photonic bandgap of a 2D triangular structure. Using numerical simulation,we can obtain the in-plane bandgap structure of a hollow-core photonic crystal fiber. In the experiments,we measured the transmission spectra of a hollow-core photonic crystal fiber and a silica rod. And using the numerical calculation we can get the relative transmission spectrum of a hollow-core photonic crystal fiber. Compared with the result of theoretical simulation,we found that they are in accordance with each other,i.e.they have the same bandgap in about the same normalized frequency.
A full-vector plane-wave method is introduced,particularly in calculating the photonic crystal in-plane photonic bandgap of a 2D triangular structure. Using numerical simulation,we can obtain the in-plane bandgap structure of a hollow-core photonic crystal fiber. In the experiments,we measured the transmission spectra of a hollow-core photonic crystal fiber and a silica rod. And using the numerical calculation we can get the relative transmission spectrum of a hollow-core photonic crystal fiber. Compared with the result of theoretical simulation,we found that they are in accordance with each other,i.e.they have the same bandgap in about the same normalized frequency.
2007, 3(1):25-26.
Abstract:
There are prominent nonlinear characteristics that we hope for the semiconductor nano-clusters doped fiber. Refractive index of fiber core can be effectively changed by adulteration. This technology can provide a new method for developing photons components. Because the semiconductor nano-cluster has quantum characteristics,Based on first-order perturbation theory and classical theory of fiber,we deduced refractive index expressions of fiber core,which was semiconductor nano-cluster doped fiber. Finally,third-order nonlinear coefficient equation was gained. Using this equation,we calculated SMF-28 fiber nonlinear coefficient. The equation shows that new third-order coefficient was greater.
There are prominent nonlinear characteristics that we hope for the semiconductor nano-clusters doped fiber. Refractive index of fiber core can be effectively changed by adulteration. This technology can provide a new method for developing photons components. Because the semiconductor nano-cluster has quantum characteristics,Based on first-order perturbation theory and classical theory of fiber,we deduced refractive index expressions of fiber core,which was semiconductor nano-cluster doped fiber. Finally,third-order nonlinear coefficient equation was gained. Using this equation,we calculated SMF-28 fiber nonlinear coefficient. The equation shows that new third-order coefficient was greater.
Long Jin
,
Gui-yun Kai
,
Ling-ling Xu
,
Bo Liu
,
Jian Zhang
,
Yan-ge Liu
,
Shu-zhong Yuan
,
Xiao-yi Dong
2007, 3(1):27-29.
Abstract:
A dual-wavelength erbium doped fiber laser with a tilted fiber Bragg grating and photonic crystal fiber is proposed and demonstrated. In the laser,a 2W EDFA provides gain for all the laser lines; the highly nonlinear photonic crystal fiber introduces dynamic energy transfer between the two wavelengths caused by four wave mixing effect,so that a stable dualwavelength oscillation at room temperature is implemented. Different switching modes can be achieved by adjusting the lateral offset between the fiber grating and the guiding single mode fiber or by varying the state of polarization in the laser cavity. The maximum of output power of the laser has reached 314 mW.
A dual-wavelength erbium doped fiber laser with a tilted fiber Bragg grating and photonic crystal fiber is proposed and demonstrated. In the laser,a 2W EDFA provides gain for all the laser lines; the highly nonlinear photonic crystal fiber introduces dynamic energy transfer between the two wavelengths caused by four wave mixing effect,so that a stable dualwavelength oscillation at room temperature is implemented. Different switching modes can be achieved by adjusting the lateral offset between the fiber grating and the guiding single mode fiber or by varying the state of polarization in the laser cavity. The maximum of output power of the laser has reached 314 mW.
2007, 3(1):30-33.
Abstract:
A fiber laser based on broadband C-band fiber grating (CFG) and high birefringence (HiBi) fiber loop mirror (FLM) is demonstrated,which uses the comb-like reflection performance of the HiBi FLM. Under different polarization states,different output lasers are gained by choosing the polarization states of the light in the cavity using the polarization controller.By this method,a single wavelength or dual wavelength laser beam can be output,and multi-wavelength oscillates can be achieved.
A fiber laser based on broadband C-band fiber grating (CFG) and high birefringence (HiBi) fiber loop mirror (FLM) is demonstrated,which uses the comb-like reflection performance of the HiBi FLM. Under different polarization states,different output lasers are gained by choosing the polarization states of the light in the cavity using the polarization controller.By this method,a single wavelength or dual wavelength laser beam can be output,and multi-wavelength oscillates can be achieved.
2007, 3(1):34-36.
Abstract:
A direction related polarizer (DRP) was used in a laser cavity to eliminate spatial hole burning of gain medium in a bidirectional Er-doped fiber ring laser. A stable operation of single longitudinal mode was achieved with comparable intensities for both clockwise and counterclockwise direction. A beat signal of 30 dB over noise was observed. This laser used as a gyroscope was demonstrated and a good linear relation between the beat frequency shift and the cavity rotation rate was acquired.
A direction related polarizer (DRP) was used in a laser cavity to eliminate spatial hole burning of gain medium in a bidirectional Er-doped fiber ring laser. A stable operation of single longitudinal mode was achieved with comparable intensities for both clockwise and counterclockwise direction. A beat signal of 30 dB over noise was observed. This laser used as a gyroscope was demonstrated and a good linear relation between the beat frequency shift and the cavity rotation rate was acquired.
2007, 3(1):37-39.
Abstract:
In this paper,the organic quantum well devices,which are similar to the type- Ⅱ quantum well of inorganic semiconductor,have been fabricated,in which the NPB (N,N'-Di-[(1-naphthalenyl)-N,N'-diphenyl]-(1,1'-biphenyl)-4,4'-diamine) and Alq3 (Tris-(8-quinolinolato)aluminum) act as the potential barrier layer and the potential well layer,respectively. In the electroluminescence,the blue shift of spectrum with the decreasing of well width is observed for the device with different well width,and this is interpreted by combination of quantum size effect and exciton confinement effect. The blue shift of spectrum with increasing applied voltage is observed for the same device,and this is interpreted in terms of polarization effect and quantum size effect.
In this paper,the organic quantum well devices,which are similar to the type- Ⅱ quantum well of inorganic semiconductor,have been fabricated,in which the NPB (N,N'-Di-[(1-naphthalenyl)-N,N'-diphenyl]-(1,1'-biphenyl)-4,4'-diamine) and Alq3 (Tris-(8-quinolinolato)aluminum) act as the potential barrier layer and the potential well layer,respectively. In the electroluminescence,the blue shift of spectrum with the decreasing of well width is observed for the device with different well width,and this is interpreted by combination of quantum size effect and exciton confinement effect. The blue shift of spectrum with increasing applied voltage is observed for the same device,and this is interpreted in terms of polarization effect and quantum size effect.
2007, 3(1):40-42.
Abstract:
A systematic analysis of the polymeric Mach-Zehnder rib waveguide is presented based on the calculation and optimization. The simulation is carried out with the Effective Index Method (EIM) and two-dimensional (2-D)Finite Difference Beam Propagation Method (FD-BPM). The large refractive index step between the consecutive polymer layers is reduced by using EIM and thus the precision of the calculation is ensured. The important parameters of the waveguide such as Y-junction angle and the separation gap are discussed and their relationships with the optical power propagation and the loss characteristics are investigated in this paper. The total loss of the optimized structure is 0.258 dB.
A systematic analysis of the polymeric Mach-Zehnder rib waveguide is presented based on the calculation and optimization. The simulation is carried out with the Effective Index Method (EIM) and two-dimensional (2-D)Finite Difference Beam Propagation Method (FD-BPM). The large refractive index step between the consecutive polymer layers is reduced by using EIM and thus the precision of the calculation is ensured. The important parameters of the waveguide such as Y-junction angle and the separation gap are discussed and their relationships with the optical power propagation and the loss characteristics are investigated in this paper. The total loss of the optimized structure is 0.258 dB.
2007, 3(1):43-46.
Abstract:
This paper reports an investigation on the electrical properties of thin film devices made by Copper(II) phthalocyanine derivative and polycarbonate (PC) composite. The conducting and injection mechanism are further discussed. Materials of a variety composition were prepared into the thin film via spin-coating. ITO and aluminum were used as the bottom and top electrode respectively. J-V characteristic was measured and the result demonstrates that at a small bias region an Ohmic contact was achieved. As the forward bias increased, the current became space charge limited. The result of AC impedance measurement indicates the device could be equivalent to a parallel RC system. The introduction of PC into the CuPc possibly reduces the charge overlapping between the aromatic rings and led to a reduction in the molecular interaction. Hence, the ac conductivity decreases sharply as PC composition increases. But no change in the transport mechanism is found. This work is supported by National Natural Science Foundation of China (20674004 and 10434030), State Key Program for Basic Research of China (2003CB314707), and Lab of Printing & Packaging Material & Technology-Beijing Area Major Laboratory, Open project (KF060303).
This paper reports an investigation on the electrical properties of thin film devices made by Copper(II) phthalocyanine derivative and polycarbonate (PC) composite. The conducting and injection mechanism are further discussed. Materials of a variety composition were prepared into the thin film via spin-coating. ITO and aluminum were used as the bottom and top electrode respectively. J-V characteristic was measured and the result demonstrates that at a small bias region an Ohmic contact was achieved. As the forward bias increased, the current became space charge limited. The result of AC impedance measurement indicates the device could be equivalent to a parallel RC system. The introduction of PC into the CuPc possibly reduces the charge overlapping between the aromatic rings and led to a reduction in the molecular interaction. Hence, the ac conductivity decreases sharply as PC composition increases. But no change in the transport mechanism is found. This work is supported by National Natural Science Foundation of China (20674004 and 10434030), State Key Program for Basic Research of China (2003CB314707), and Lab of Printing & Packaging Material & Technology-Beijing Area Major Laboratory, Open project (KF060303).
2007, 3(1):47-49.
Abstract:
Based on polymer microstructured optical fibers (PMOF) and selective liquid crystal injection technology,a novel temperature control tunable attenuator is designed theoretically in this paper. In our experiments,PMMA microstructured optical fibers with high performance are drawn successfully and the selective injection of liquid crystal 5CB into microholes is realized. The tunable attenuator is fabricated with an extinction ratio of over 60 dB,which agrees well with the design.
Based on polymer microstructured optical fibers (PMOF) and selective liquid crystal injection technology,a novel temperature control tunable attenuator is designed theoretically in this paper. In our experiments,PMMA microstructured optical fibers with high performance are drawn successfully and the selective injection of liquid crystal 5CB into microholes is realized. The tunable attenuator is fabricated with an extinction ratio of over 60 dB,which agrees well with the design.
2007, 3(1):50-53.
Abstract:
A novel second-order nonlinear optical chromophore (DCDHF-2-V) was synthesized from 3-Hydroxy-3-methyl-2-butanae, propanedinitrile and 4-diethylaminobenzaldehyde by aldol condensation reaction. Molecular structural characterization was investigated by elemental analysis, FTIR, and 1H-NMR spectra. The melting point obtained from DSC thermogram was almost 251 °C, and the compound shows a thermal stability up to 270 °C. Second-order NLO properties of the chromophore were measured by solvatochromic method. From the quantum-mechanical two-level model, it can be obtained that the μg β value of DCDHF-2-V is 6520 × 10−48esu at the wavelength of 1064 nm.
A novel second-order nonlinear optical chromophore (DCDHF-2-V) was synthesized from 3-Hydroxy-3-methyl-2-butanae, propanedinitrile and 4-diethylaminobenzaldehyde by aldol condensation reaction. Molecular structural characterization was investigated by elemental analysis, FTIR, and 1H-NMR spectra. The melting point obtained from DSC thermogram was almost 251 °C, and the compound shows a thermal stability up to 270 °C. Second-order NLO properties of the chromophore were measured by solvatochromic method. From the quantum-mechanical two-level model, it can be obtained that the μg β value of DCDHF-2-V is 6520 × 10−48esu at the wavelength of 1064 nm.
2007, 3(1):54-56.
Abstract:
The forming and activation of the conductive films are studied experimentally. The power supply,a peak-to-peak 30 V triangle profile voltage,is applied to three kinds of conductive films that contain 0.25%,0.5%,and 1% of palladium respectively. In the experiments we contrasted the values of related parameter in different conditions,observed the lumi nous spots on the anode panel,dealt with and analyzed the related data,and compared the positions and the amount of the luminous spots. We have gotten the conclusion that there is a threshold value Uth. The emission current Ie will increase rapidly when the device voltage Uf is greater than Uth. And the emission current Ie could be controlled by the device voltage Uf.The positions of the luminous spots on the anode panel are related with the device voltage Uf.
The forming and activation of the conductive films are studied experimentally. The power supply,a peak-to-peak 30 V triangle profile voltage,is applied to three kinds of conductive films that contain 0.25%,0.5%,and 1% of palladium respectively. In the experiments we contrasted the values of related parameter in different conditions,observed the lumi nous spots on the anode panel,dealt with and analyzed the related data,and compared the positions and the amount of the luminous spots. We have gotten the conclusion that there is a threshold value Uth. The emission current Ie will increase rapidly when the device voltage Uf is greater than Uth. And the emission current Ie could be controlled by the device voltage Uf.The positions of the luminous spots on the anode panel are related with the device voltage Uf.
Wen-cai Jing
,
Xiao-jingi Li
,
Kun Liu
,
Tian-hua Xu
,
Yi-mo Zhang
,
Hong-xia Zhang
,
Da-gong Jia
,
Gang-Ding Peng
2007, 3(1):57-61.
Abstract:
A distributed polarization-mode coupling measurement system was designed and implemented using white light interferometry. It can be used for the measurement of polarization mode coupling in a high-birefringence fiber of up to 1 km. This system can be used in both fiber-optic sensors and optical fiber communications. Wavelet Transform was adopted in data processing to improve the signal-noise-ratio. The signal-noise-ratio of this system was improved more than 15 dB after denoising. The influence of denoising threshold on signal-noise-ratio and measurement accuracy was also discussed. Hilbert Transform and non-linear regression can be used in conjunction with Wavelet Transform to enhance the signal-noise-ratio and spatial resolution of this system.
A distributed polarization-mode coupling measurement system was designed and implemented using white light interferometry. It can be used for the measurement of polarization mode coupling in a high-birefringence fiber of up to 1 km. This system can be used in both fiber-optic sensors and optical fiber communications. Wavelet Transform was adopted in data processing to improve the signal-noise-ratio. The signal-noise-ratio of this system was improved more than 15 dB after denoising. The influence of denoising threshold on signal-noise-ratio and measurement accuracy was also discussed. Hilbert Transform and non-linear regression can be used in conjunction with Wavelet Transform to enhance the signal-noise-ratio and spatial resolution of this system.
2007, 3(1):62-64.
Abstract:
An 800 nm band fiber Bragg grating sensing interrogation system using tilted FBG as the core wavelength division component is presented. A charge coupled device (CCD) linear array is put on the focal plane of the lens to detect the light. TFBG is used to tap light out of the fiber core to fiber cladding. The sensing wavelength is 795 to 830 nm, with accuracy of 20 pm and scan speed 100Hz. Using FBG sensor, we achieve the temperature sensitivity of 1.8 °C and strain sensitivity of 18 μ ɛ. This work is suppoted by National Nature Science Foundation of China(60577018),the 863 National High Technology Prograrm of china (Grant No.2006AA01Z217),and the open Project foudation of key laboratory of Opto-eletronic Infr mation Science and Technology luinistry of Eolucation in Nankai university
An 800 nm band fiber Bragg grating sensing interrogation system using tilted FBG as the core wavelength division component is presented. A charge coupled device (CCD) linear array is put on the focal plane of the lens to detect the light. TFBG is used to tap light out of the fiber core to fiber cladding. The sensing wavelength is 795 to 830 nm, with accuracy of 20 pm and scan speed 100Hz. Using FBG sensor, we achieve the temperature sensitivity of 1.8 °C and strain sensitivity of 18 μ ɛ. This work is suppoted by National Nature Science Foundation of China(60577018),the 863 National High Technology Prograrm of china (Grant No.2006AA01Z217),and the open Project foudation of key laboratory of Opto-eletronic Infr mation Science and Technology luinistry of Eolucation in Nankai university
2007, 3(1):65-68.
Abstract:
A simple method used for simultaneous measurement of phase retardation and optic axis of wave plate by employing 1/4 wave plate is demonstrated. The theoretical analysis of the measuring principle is presented in detail. In the measurement,after adjusting a standard 1/4 wave plate and the fast (slow) axis of the plate to be measured parallel to the pass axis of the polarizer,the plate to be measured is rotated by 450 counterclockwisly. A stepping motor is used to rotate the analyzer. The experimental data are collected by a photodetector and then sent to a computer. According to the output data curve,the phase retardation and optic axis of the plate to be measured can be obtained simultaneously. To test the feasibility of the method,a λ/2 and a λ/8 wave plates are used as examples to demonstrate the measurement procedures. The phase retardation measurement accuracy is better than 0.5 × 10-2. This method can be used to measure the arbitrary phase retardation conveniently.
A simple method used for simultaneous measurement of phase retardation and optic axis of wave plate by employing 1/4 wave plate is demonstrated. The theoretical analysis of the measuring principle is presented in detail. In the measurement,after adjusting a standard 1/4 wave plate and the fast (slow) axis of the plate to be measured parallel to the pass axis of the polarizer,the plate to be measured is rotated by 450 counterclockwisly. A stepping motor is used to rotate the analyzer. The experimental data are collected by a photodetector and then sent to a computer. According to the output data curve,the phase retardation and optic axis of the plate to be measured can be obtained simultaneously. To test the feasibility of the method,a λ/2 and a λ/8 wave plates are used as examples to demonstrate the measurement procedures. The phase retardation measurement accuracy is better than 0.5 × 10-2. This method can be used to measure the arbitrary phase retardation conveniently.
2007, 3(1):69-72.
Abstract:
In allusion to the character of monocular image sequences,a method based on extended Kalman filtering to predict the aircraft pose of image sequences is proposed. With α-β-γstable state filtering technique,a mathematics model is built to realize the prediction of aircraft pose of image sequences. In the model,not only the influence of noise during the image process is considered,but also the shortcoming of low precision in the constant velocity model is overcomed. The derivation of acceleration is considered as white noise. The predictive curve plotted with Matlab proves that the maximum of error of using this method is about 3. So its precision is higher and error standard deviation is lower than those of the constant velocity model.
In allusion to the character of monocular image sequences,a method based on extended Kalman filtering to predict the aircraft pose of image sequences is proposed. With α-β-γstable state filtering technique,a mathematics model is built to realize the prediction of aircraft pose of image sequences. In the model,not only the influence of noise during the image process is considered,but also the shortcoming of low precision in the constant velocity model is overcomed. The derivation of acceleration is considered as white noise. The predictive curve plotted with Matlab proves that the maximum of error of using this method is about 3. So its precision is higher and error standard deviation is lower than those of the constant velocity model.
2007, 3(1):73-77.
Abstract:
Mesoscopic damped mutual capacitance coupled double resonance circuit is quantized by the method of damped harmonic oscillator quantization. Hamiltonian is diagonalized by the method of unitary transformation. The energy spectra of this circuit are given. The quantum fluctuations of the charge and current of each loop are investigated by the method of thermofield dynamics (TFD) in thermal excitation state,thermal squeezed vacuum state,thermal vacuum state and vacuum state. It is shown that the quantum fluctuations of the charge and current are related to not only circuit inherent parameter and coupled magnitude,but also quantum number of excitation,squeezed coefficients,squeezed angle and environmental temperature. And the quantum fluctuations increase with the increase of temperature and decay with time.
Mesoscopic damped mutual capacitance coupled double resonance circuit is quantized by the method of damped harmonic oscillator quantization. Hamiltonian is diagonalized by the method of unitary transformation. The energy spectra of this circuit are given. The quantum fluctuations of the charge and current of each loop are investigated by the method of thermofield dynamics (TFD) in thermal excitation state,thermal squeezed vacuum state,thermal vacuum state and vacuum state. It is shown that the quantum fluctuations of the charge and current are related to not only circuit inherent parameter and coupled magnitude,but also quantum number of excitation,squeezed coefficients,squeezed angle and environmental temperature. And the quantum fluctuations increase with the increase of temperature and decay with time.
2007, 3(1):78-80.
Abstract:
A novel single-ring absolute optical shaft encoder is designed by studying the encoding principle of traditional absolute optical shaft encoder in this paper. The description of the orientation algorithm of the encoder is specified,and an example for explaining the orientation arithmetic is given,which indicates that the theory of the encoder works. The visual interface to acquire signals of CCD is shown with VB,which provides reliable foundation to process data. The effective factors of measurement precision of the encoder are analyzed.
A novel single-ring absolute optical shaft encoder is designed by studying the encoding principle of traditional absolute optical shaft encoder in this paper. The description of the orientation algorithm of the encoder is specified,and an example for explaining the orientation arithmetic is given,which indicates that the theory of the encoder works. The visual interface to acquire signals of CCD is shown with VB,which provides reliable foundation to process data. The effective factors of measurement precision of the encoder are analyzed.
2007, 3(1):I0004-I0004.
Abstract:
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