We study the Gaussian laser transmission in lithium niobate crystal（LiNbO3） by using the finite element method to solve the electromagnetic field＇s frequency domain equation and energy equation. The heat generated ...We study the Gaussian laser transmission in lithium niobate crystal（LiNbO3） by using the finite element method to solve the electromagnetic field＇s frequency domain equation and energy equation. The heat generated is identified by calculating the transmission loss of the electromagnetic wave in the birefringence crystal, and the calculated value of the heat generated is substituted into the energy equation. The electromagnetic wave＇s energy losses induced by its multiple refractions and reflections along with the resulting physical property changes of the lithium niobate crystal are considered.Influences of ambient temperature and heat transfer coefficient on refraction and walk-off angles of O-ray and E-ray in the cases of different incident powers and crystal thicknesses are analyzed. The E-ray electrical modulation instances, in which the polarized light waveform is adjusted to the rated condition via an applied electrical field in the cases of different ambient temperatures and heat transfer coefficients, are provided to conclude that there is a correlation between ambient temperature and applied electrical field intensity and a correlation between surface heat transfer coefficient and applied electrical field intensity. The applicable electrical modulation ranges without crystal breakdown are proposed. The study shows that the electrical field-adjustable heat transfer coefficient range becomes narrow as the incident power decreases and wide as the crystal thickness increases. In addition, it is pointed out that controlling the ambient temperature is easier than controlling the heat transfer coefficient. The results of the present study can be used as a quantitative theoretical basis for removing the adverse effects induced by thermal deposition due to linear laser absorption in the crystal, such as depolarization or wave front distortion, and indicate the feasibility of adjusting the refractive index in the window area by changing the heat transfer boundary conditions in a wide-spectrum laser.展开更多
This paper reports that the thermo-optic coefficient （dn/dT） as well as thermal expansion coefficients （β） of DR1/PMMA polymer film are measured for both TE （transversal electric） and TM （transversal magnetic...This paper reports that the thermo-optic coefficient （dn/dT） as well as thermal expansion coefficients （β） of DR1/PMMA polymer film are measured for both TE （transversal electric） and TM （transversal magnetic） polarizations by using an attenuated total reflection configuration at the wavelengths of 832nm. The thermo-optic coefficients of DR1/PMMA are negative and as high as the order of 10^-4/℃. The influences of dopant concentration, poling process and photobleaching process on the thermo-optic properties of DR1/PMMA are also investigated.展开更多
The thermo-optic effect in the lateral-carrier-injection pin junction SOI ridge waveguide is analyzed according to the thermal field equation.Numerical analysis and experimental results show that the thermo-optic effe...The thermo-optic effect in the lateral-carrier-injection pin junction SOI ridge waveguide is analyzed according to the thermal field equation.Numerical analysis and experimental results show that the thermo-optic effect caused by carrier injection is significant in such devices,especially for small structure ones.For a device with a 1000μm modulation length,the refractive index rise introduced by heat accounts for 1/8 of the total effect under normal working conditions.A proposal of adjusting the electrode position to cool the devices to diminish the thermal-optic effect is put forward.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51176039)
文摘We study the Gaussian laser transmission in lithium niobate crystal（LiNbO3） by using the finite element method to solve the electromagnetic field＇s frequency domain equation and energy equation. The heat generated is identified by calculating the transmission loss of the electromagnetic wave in the birefringence crystal, and the calculated value of the heat generated is substituted into the energy equation. The electromagnetic wave＇s energy losses induced by its multiple refractions and reflections along with the resulting physical property changes of the lithium niobate crystal are considered.Influences of ambient temperature and heat transfer coefficient on refraction and walk-off angles of O-ray and E-ray in the cases of different incident powers and crystal thicknesses are analyzed. The E-ray electrical modulation instances, in which the polarized light waveform is adjusted to the rated condition via an applied electrical field in the cases of different ambient temperatures and heat transfer coefficients, are provided to conclude that there is a correlation between ambient temperature and applied electrical field intensity and a correlation between surface heat transfer coefficient and applied electrical field intensity. The applicable electrical modulation ranges without crystal breakdown are proposed. The study shows that the electrical field-adjustable heat transfer coefficient range becomes narrow as the incident power decreases and wide as the crystal thickness increases. In addition, it is pointed out that controlling the ambient temperature is easier than controlling the heat transfer coefficient. The results of the present study can be used as a quantitative theoretical basis for removing the adverse effects induced by thermal deposition due to linear laser absorption in the crystal, such as depolarization or wave front distortion, and indicate the feasibility of adjusting the refractive index in the window area by changing the heat transfer boundary conditions in a wide-spectrum laser.
基金Project supported by the National Science Foundation of China （Grant No 60237010） and Exploring Foundation of National High-Tech ICF Committee of China （Grant No 2003AA84tslT）.
文摘This paper reports that the thermo-optic coefficient （dn/dT） as well as thermal expansion coefficients （β） of DR1/PMMA polymer film are measured for both TE （transversal electric） and TM （transversal magnetic） polarizations by using an attenuated total reflection configuration at the wavelengths of 832nm. The thermo-optic coefficients of DR1/PMMA are negative and as high as the order of 10^-4/℃. The influences of dopant concentration, poling process and photobleaching process on the thermo-optic properties of DR1/PMMA are also investigated.
基金Project supported by the Natural Basic Research Program of China(No.2007CB613405)the National Natural Science Foundation of China(No.60777015)+1 种基金the Science & Technology Program of Zhejiang Province,China(No.2007C21022)the Opened Fund of State Key Laboratory on Integrated Optoelectronics,China.
文摘The thermo-optic effect in the lateral-carrier-injection pin junction SOI ridge waveguide is analyzed according to the thermal field equation.Numerical analysis and experimental results show that the thermo-optic effect caused by carrier injection is significant in such devices,especially for small structure ones.For a device with a 1000μm modulation length,the refractive index rise introduced by heat accounts for 1/8 of the total effect under normal working conditions.A proposal of adjusting the electrode position to cool the devices to diminish the thermal-optic effect is put forward.
