2004 Vol. 25, No. 4

Theoretical Study
A Research on Heat Radiation Spectrum Characteristics of Moxibustion Therapy
HONG Wen-xue, CAI Jian-hong, JING Jun
2004, 25(4): 1-3.
The heat radiation spectrum of two types of moxibustions have been measured by applying grating-spectrometer in order to learn the physical characterstic of moxibustion in traditional Chinese medicine.The measured results show that there is hardly any visible spectrum of moxibustion and the wavelength corresponding to peak value is about 3.5um in the far-infrared band.According to the results we confirmed that the spectrum distribution of the moxibustion is mainly in the far-infrared region very closed to near-infrared.
The Improvement of Inverse Wentzel-Kramer-Brillouin(WKB) Method
ZHANG Chang-ming, LIU Yong-zhi, ZHANG Xiao-xia, GAN Xiao-yong
2004, 25(4): 4-8.
The improvement of inverse Wentzel-Kramer-Brillouin(WKB) method for refractive-index profile of a graded-index planar waveguide calculated numerically from the eigenvalue equation under the WKB approximation is extended.The Practicality of this method is demonstrated by application to three types of refractive index distribution(exponetial,Gaussian and step refractive index distribution).The refractive-index profiles caculated from the corresponding effective-index function,which can be found approximately by least-square fitting of a set of measured effective indexes,agree well with the exact profile,The absolute errors of the waveguide surface indexes calculated,with respect to the exact values,are about 0.1%.
Matrix Method to Express the Reflecting Process of Beam
PAN Han-jun, LIU Ya
2004, 25(4): 9-13.
In this paper,the character of the equation for reflected beam is discussed,a concept of reflection matrix is introducted,and the essentail meaning of reflection matrixes is analysed.It gets the simplest reflection matrix,This paper provides the evidence and method for the mathematics computing of the reflecting process of the beam of the beam on a single echoplane and the continuous beam reflection on multi-echoplane.
Research on Faraday Effect in Magneto-optic Glass
HUANG Hai, BU Sheng-li
2004, 25(4): 14-17.
In this paper,the Faraday effect in magneto-optic glass are introduced,and the experiments are preformed on magneto-optic glass experimental sample ZF1 and ZF6 respectively.The Relationship between the azimuth rotation of the polarization plane of the linearly polarized optical beam and magnetic field strength is indicated by experiment.The Verdet constant under different magnetic field strength(the operating light wavelength is fixed all the time) is calcuated.The experimental results are quite well in agreement with the theoretical value.
A 3-D Code for OCDMA System
ZHOU Xiu-li, HU Yu, TAN Qing-gui
2004, 25(4): 18-20.
Based on Reed-Solomon sequence arithmetic,we put forward a new kind of space/wavelength/time spread three-dimensional optical code for OCDMA system,and performed some mathematical analyses.Compared with 2-D code,3-D optical code has much bigger capacitance,better bandwidth efficiency and lower error probability,and enhances the feasibility of the OCDMA system.
MPCP Protocol in EPON System
ZHANG Duo-ying, LI Xue-yi, LIU Wei-ping, LI Jian-dong
2004, 25(4): 21-25.
Based on the detailed research on EPON system which emerging in recent years,this article focuses on the special point to multi-point topology in EPON system,and one point to multipoint control protocol(MPCP)which used for controlling and managing the EPON system has been discussed in detail.MPCP includs the structure of the 5 controlling frams and the meaning of each code.The principles of starting registration,ranging compensation time delay compensation and time slot allocation are also analyzed in this paper.
Optical Design
An All-Optical Network OADM Design Based on Fiber Bragg Grating
WANG Jian-zhong, LIU Yong-zhi
2004, 25(4): 26-28.
We propose a new OADM structure design,which uses a multi-ports optical circulator (OC) with fiber Bragg grating(FBG) and reduces the number of circulators.Therefore,it is cost-effective,If we want to add-drop one wavelengh,only one FBG will be needed,and if we want to add-drop many wavelengths,2 m FBGs must be needed.The computer simulation experiment shows that the loss of this structure is lower than that of H.Yuan's structure.It can drop many wavelengths.With the development of Internet,the much faster transport networks will be needed.The structure is important for aii-optical network realization.
Night Vision
Development of Night Vision Instrument in Air-Defense
WANG Jian-hua
2004, 25(4): 29-30.
The lack of the night vision instrument is the bottleneck of modern night air-defense for the PLA.In the advanced air-defense fire-control area,the cooled infrared thermal imaging system can be used,It is compatible with the situation of our country that the low-light-level and the uncooled infrared technology could be used in our old air-defense fire-control systems,and it is actual and feasible.
Research on Thermal cleaning Technique for GaAs Photocathode
SHI Feng
2004, 25(4): 31-32.
The surface of the active layer of GaAs photocathode must reach the atomically clean surface before Cs-O activeness.The most effective method,which is used quite often,is the hight-temperature thermal cleaning one.It is very difficult to measure precisely the surface temperature of a photocathode in a vacuum system during the thermal cleaning. This paper discusses how to use a quadrupole mass spectroscope to analyzed the whole process of thermal cleaning before the activeness of GaAs photocathode,thus the temperature and technique of the optimal thermacleaning is determine.The problem for the thermal cleaning technique taken before GaAs photocathode activeness is well rolved.
Infrared Technology
Antijamming Methods of Counter-Infrared-Interference-Missile by Using Cross-Shaped Detector Array
GUO Xin-jun, JIN Wei-qi, WANG Ji
2004, 25(4): 33-36.
The principles of cross-shaped detector array and the infrared decoy are introduced. Seven kinds of antijamming methods,such as time correlated choice and field-of-view shrinkage, inertial track,real-time memory criterion,amplitude discrimination, pulse-width discrimination, pulse-amplitude time sequence discrimination and pulse-width amplitude discrimination for Counter-Infrared-Interference-Missile(CIRIM) with the cross-shaped detector array are given. The condition of the methods to be used is presented at last.
Research on the NETD Mathematical Model for Scanning Thermal Imaging System
LI Xu-dong, AI Ke-cong, WANG Wei
2004, 25(4): 37-40.
In this paper,the merits and shortcomings of the most representative ten kinds of the noise equivalent temperature difference(NETD) models in several decades are discussed, and the new prevalent NETD model is set up. The new NETD model eliminates the great f/# effect from the optical system. The effect of the duty ratio in the math model is taken into account and two options of spectrum filtering functions (Fλ1,Fλ2) are added. The new model which has been established by us can be well used in the performance evaluation of temperatur sensitivity of the thermal imaging system.
Application And Equivalent Analysis of Detection Distance of Infrared Surveillance Equipment
HAO Ji-ping, HUANG Ping-hua, DU Cheng-gong
2004, 25(4): 41-44.
The effective ranging of IR photodetection equipments, in addition to the relation with the performance of the equipment itself, is restricted by ambient temperature, relative humidity, visibility ratio and target characteristics etc. To decide whether the effective ranging of IR photodetection equipments is up to standard is now a striking problem in the test-range testing,because the standard conditions are hard to be established in a test range and any real target can be hardly used under test. In this paper, the effective ranging of IR photodetection equipments is calculated by using the traditional formulas calculating the effective ranging, by counting a great number of testing data and by taking an actual measurement for the optical radiation characteristic of some real objects. The important parameters in the computation formulas are quantized. According to the requirement of the defined effective ranging at the standard condition,the effective ranging which should be within reach in the condition of the field test(i.e.the equivalent ranging)is calculated.And with this,it can be decided whether the effective ranging obtained in the actual measurement during the real testing may meet the define requirement.
Laser Technology
Characteristic and application of S2 molecule spectrum
ZHAO Xu-guang
2004, 25(4): 45-47.
S2molecule laser based on sea exploring and communication to submarine has been researched. It has advantages over other lasers. Potential curves and spectral characteristic of S2 molecule are introduced.Now good progress has been made and the firm foundation for the miniature S2 laser with transversely pulsed quick discharge has been laid.
Fiber Optics
Study on Refractive Index and Concentration Sensor Based on Long-Period Fiber Grating
LI Zhi-quan, WANG Li, HUANG Li-juan, ZHANG Xiao-ming, ZHU Dan-dan
2004, 25(4): 48-50.
Based on the simplified three-layered model,long-period fiber grating's sensitivity to the surrounding refractive index and concentration is analyzed with the couple-mode theory. Computer was use to simulate and calculate the numerical value of the grating, and to achieve the relation between the resonance wavelength of LPG's transmittance and the surrounding refractive index and concentration. The experimental results fit the computer simulation results well.
Thin Film
Analysis of Error Sensitivity and Allowable Error of Optical Film, and Computer Controll in Production
XIA Zhi-lin, XUE Yi-yu, ZHANG You-ling, LIU Wei-hua
2004, 25(4): 51-55.
There is a distinction between the film optical characteristic calculated in theory and the optical characteristic appearing in actual measurement. It can be caused by many reasons, such as the incomplete theoretical model, the structural change when the film is stored away for a long time and the fabrication error. The corresponding methods in allusion to the cause to eliminate or avert the error is proposed. The film thickness and refractive index is the key to film preparation.In this paper, we analyzed the error of film thickness and refractive index caused by the optical control system, and also analysed the allowable error. In the end, we put forward the thought of computer real time optimization.
Opto-electronic Device
The Manufacture and Application of Periodically Poled Lithium Niobate
WANG Yong-gang, MA Xiao-yu
2004, 25(4): 56-58.
The principle, manufacture and application of periodically poled lithium niobate(PPLN) are introduced in detail.PPLN develops rapidly with the character of effective nonlinear coefficient and it is one order of magnitude higher than that of common bulk crystal. PPLN is manufactured by applying external field, proton exchange and so on. In recent years, its technology and effect iveness of the light to light has made much progress. PPLN can be used to frequency doubling of solid-state laser, parametric oscillation and even to doubling frequency of semiconductor laser. Whether the PPLN is used has become the conclusive factor to develop the traditional nonlinear laser source.
Study of Passive Q-switched Unit of Nd∶YAG Laser Using Ion-Implanted GaAs
LI Zhao-yang, WANG Yong-gang, HUANG Liu
2004, 25(4): 59-62.
Proceeding from the SI-GaAs's energy level structure, the feasibility of using the ion-implanted GaAs semiconductor material as a passive Q-switched unit of solid-state lasers is discussed. The dynamic characteristic of GaAs used as passive Q-switch device is investigated experimentally.In the experiment, flat-flat cavity was adopted and (Nd∶YAG) was pumped by a xenon lamp,and the Q-switched waveform of 62ns single pulse width was obtained at repetition rate of 1Hz.
Determination of Aspheric Reference Sphere by Tri-point Method
WANG Hong-jun, TIAN Ai-ling, DU Yu-jun
2004, 25(4): 63-65.
Based on the condition of aspheric production, the method how to get the aspheric reference sphere is presented in this paper. The calculating method of the reference sphere is analyzed in detail, by calculating the reference sphere of a paraboloid and comparing it with the result of the least square method.The tri-point method has a merit of simple calculation and it is adapted to the process of the craft.