Improved waveguide designs for 9.0μm GaAs-based quantum cascade laser （QCL） structures are presented. Modal losses and confinement factors are calculated for TM modes with the transfer matrix method （TMM） and eff...Improved waveguide designs for 9.0μm GaAs-based quantum cascade laser （QCL） structures are presented. Modal losses and confinement factors are calculated for TM modes with the transfer matrix method （TMM） and effective index method （EIM）. The thicknesses of the cladding layer and waveguide layer, the ridge-width, and the cavity length are all taken into account. Appropriate thicknesses of epilayers are given with lower threshold gain and more economical material growth time.展开更多
The traditional method of measuring Doppler Effect is either reflection or dispersiion. This article clarifies that it can also verify the Doppler Effect with the refraction method. We have designed the experimental s...The traditional method of measuring Doppler Effect is either reflection or dispersiion. This article clarifies that it can also verify the Doppler Effect with the refraction method. We have designed the experimental system with the method of optical heterodyne, using the refraction light beam from a prism, and made the experiment. The experimental results are in accordance with the theoretical calculation. It is very useful in some particular case, such as in Negative- Index Materials（NIM）, to verify the Doppler Effect with this method.展开更多
The effective index of the cladding fundamental space-filling mode in photonic crystal fiber (PCF) is simulated by the effective index method. The variation of the effective index with the structure parameters of the ...The effective index of the cladding fundamental space-filling mode in photonic crystal fiber (PCF) is simulated by the effective index method. The variation of the effective index with the structure parameters of the fiber is achieved. For the first time, the relations of the V parameter of Yb3+-doped PCF with the refractive index of core and the structure parameters of the fiber are provided. the single-mode characteristics of large-core Yb3+-doped photonic crystal fibers with 7 and 19 missing air holes in the core are analyzed. The large-core single-mode Yb3+-doped photonic crystal fibers with core diameters of 50 μm, 100 μm and 150 μm are designed. The results provide theory instruction for the design and fabrication of fiber.展开更多
文摘Improved waveguide designs for 9.0μm GaAs-based quantum cascade laser （QCL） structures are presented. Modal losses and confinement factors are calculated for TM modes with the transfer matrix method （TMM） and effective index method （EIM）. The thicknesses of the cladding layer and waveguide layer, the ridge-width, and the cavity length are all taken into account. Appropriate thicknesses of epilayers are given with lower threshold gain and more economical material growth time.
文摘The traditional method of measuring Doppler Effect is either reflection or dispersiion. This article clarifies that it can also verify the Doppler Effect with the refraction method. We have designed the experimental system with the method of optical heterodyne, using the refraction light beam from a prism, and made the experiment. The experimental results are in accordance with the theoretical calculation. It is very useful in some particular case, such as in Negative- Index Materials（NIM）, to verify the Doppler Effect with this method.
基金supported by the National Natural Science Foundation of China (Nos.60637010 and 60978028)the National Basic Research Program of China (No.2010CB327604)+1 种基金the Young Scientists Fund of the Natural Science Foundation of Hebei Province (Nos.F2010001313 andF2010001291)the Science and Technology Development Program of Qinhuangdao of Hebei Province (No.201001A076)
文摘The effective index of the cladding fundamental space-filling mode in photonic crystal fiber (PCF) is simulated by the effective index method. The variation of the effective index with the structure parameters of the fiber is achieved. For the first time, the relations of the V parameter of Yb3+-doped PCF with the refractive index of core and the structure parameters of the fiber are provided. the single-mode characteristics of large-core Yb3+-doped photonic crystal fibers with 7 and 19 missing air holes in the core are analyzed. The large-core single-mode Yb3+-doped photonic crystal fibers with core diameters of 50 μm, 100 μm and 150 μm are designed. The results provide theory instruction for the design and fabrication of fiber.
