Optical Device|19 Article(s)
The Focus Diffraction Property of Axicons Illuminated by Incident Spherical Wave
[in Chinese], and [in Chinese]
Acta Photonica Sinica
  • Publication Date: Jan. 01, 2005
  • Vol. 34 Issue 1 126 (2005)
The Research on Measuring the Extinction Ratio of Polarizing Prism Accurately
HAO Chong, WU Yi-ming, LU Wei-guo, XIAO Mao-sen, and LI Chun-yan
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2014
  • Vol. 43 Issue 12 1223001 (2014)
Design and Optimization of Beam-splitting Polarizing Filter Based on Two-dimensional Photonics Crystal
WANG Chen-ge, ZHANG Cai-ni, CHEN Kan, HUANG Teng-chao, SHU xiao-wu, and LIU Cheng
A kind of beam-splitting polarizing filter based on two-dimensional photonics crystal was proposed.The photonic bandgap was calculated by plane wave expansion method to confirm the micro-structure parameters,with which single polarized beam in 1550nm can be obtained;Finite-different time-domain method was used to optimize the 90° bending buffer layer and impacting wall of beam-splitter.This device indeed is a waveguide fabricated by introducing defect in two-dimensional photonics crystal array,a single polarization source can be obtained by using photonics band gap and 90° linear defect to filter a certain polarization completely off.By the construction of Y-shaped defect,an approximate splitting ration of 1: 1 is achieved.Through the optimization of the 90° linear defect and buffer layer,a ratio of 68% between the output power and input power is finally gained.
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2014
  • Vol. 43 Issue 12 1223002 (2014)
Structural Design and Optimization of Absorption of Thin Film Solar Cells Based on Grating Structure
GENG Hao-ke, SUN Xiao-hong, ZHANG Xu, LIANG Jian, and LIU Wen
A thin film solar cell with a grating in the layer was designed to increase the absorption of gallium arsenide thin-film layer.By using rigorous coupled wave method,the absorption efficiency in the range of 280~900 nm was analyzed for GaAs layer with single and double rectangular gratings.When the thickness of absorption layer obtained under certain circumstances,the rate of absorption compared to the rectangular grating structure of the non patterned absorber layer was greatly improved.The absorption rate of double rectangular grating increased by at least 10% over single rectangular grating and 20% over non patterned,which is more obvious.The results indicate that,by designing the structure,random reflection photonic in grating increases the effect of time and distance in the light absorption layer,enhanced the absorption rate and finally improve the photoelectric conversion efficiency of the thin film solar cell.
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2014
  • Vol. 43 Issue 12 1223003 (2014)
A Tunable Terahertz Bandpass Filter with a Slit Aperture Flanked by Symmetrically Distributed Parallel Grooves on Both Sides
YUAN Ming-hui, and ZHAO Di
A low-cost and high efficient tunable terahertz (THz) bandpass filter on aluminum slab with a center slit flanked by symmetrically distributed parallel grooves on both sides was experimentally analyzed by the terahertz time domain spectroscopy (THz-TDS).Experimental results show that a high centre transmittance (>95%) can be obtained at 0.33 THz because of the enhanced transmission effect induced by symmetrically coupled spoof surface plasmon polaritons (SSPPs).And the transmitted THz wave radiated from the slit aperture has a small divergence angle (approximately 5°).Moreover, the transmission peak splits into two peaks: the low-frequency peak shows redshift and the high-frequency peak shows blueshift when the incident tilting angle increases, and the transmission peak blue shifts when the incident pitching angle increases.
Acta Photonica Sinica
  • Publication Date: Mar. 01, 2015
  • Vol. 44 Issue 3 323003 (2015)
Studying of Output Power Combining for Cascaded Travelling-wave Photodiode Arrays
WEN Hua-feng, NIE Qiu-hua, LIU Tai-jun, XU Tie-feng, YING Xiang-yue, CLARK Kevin, and LI Ying-feng
In order to fabricate the high-power high-bandwidth photodector for radio-over-fiber communication, a optical-to-electrical conversion circuit of cascaded traveling-wave detector arrays for power combining was proposed. Traveling-wave photodiodes were cascaded and connected with inductors based on the structure of traveling-wave detector arrays to obtain high-power high-bandwidth radio frequency signals. The optical-to-electrical conversion circuit was simulated with EDA tools. The simulation results show that the circuit combines the signals of the cascaded photodiodes effectively, which makes the bandwidth increase significantly. The results agree well with the theortetical analysis. In addition, circuits analysis indicates that the frequency bandwidth of the RF signal incereases effectively as the characteristic impendance increases.
Acta Photonica Sinica
  • Publication Date: Mar. 01, 2015
  • Vol. 44 Issue 3 323001 (2015)
A Novel of Pulse Width Modulation for Eliminating the Dynamic False Contours in LED Display
ZHOU Xiao-yuan, YUAN Sheng-chun, LI-hui, ZHANG Jian-qi, and ZHAO Xiao-ming
Aimed at the problem of dynamic false contour in LED display when playing the motion images, a novel of PWM method named concentrated gated pulse width modulation was proposed. Based on the GPWM, the approach fixes the decimal subfields on the center of one PWM period, and then figures out the number of subfields corresponding to the integer weight bits, and locate them near the decimal subfields. Theoretical analysis and experiments show that CGPWM has the similar lighting function with linear PWM, and consequently reduces the average DFC values between any two gray levels from 0.6 under the control of GPWM to 0.2. CGPWM can eliminate DFC effectively while maintaining high refresh frequency and rich gray levels, and thus improve the image quality greatly. Furthermore, the processing to implement CGPWM is simple without extra hardware.
Acta Photonica Sinica
  • Publication Date: Feb. 01, 2015
  • Vol. 44 Issue 2 223002 (2015)
Investigation on Slow Light in Photonic Crystal Coupled-cavity Waveguide
DONG Xiao-wei, QUAN Wei, and LIU Wen-kai
A slow light photonic crystal coupled-cavity waveguide by introducing two additional holes into the single line-defect structure was proposed. The characteristics of slow light in the coupled-cavity waveguide were investigated with Plane Wave Expansion (PWE) method. Influences of the boundary rows shift and the coupled-cavity length on the dispersion and the group velocity of device were studied. Compared with the boundary rows shift method, the group velocity is reduced to 0.03c (c is the light velocity in vacuum) by modifying the coupled-cavity, meanwhile the effective wavelength range is close to 20nm. Finally, the transmission field distribution under different incident wavelength was analysed with Finite Difference Time Domain (FDTD) method. A good transmission character of the proposed structure is verified by researching transmission field distribution under different incident wavelength in photonic crystal coupled cavity waveguides.
Acta Photonica Sinica
  • Publication Date: Feb. 01, 2015
  • Vol. 44 Issue 2 223001 (2015)
Stability of Phase Compensator in Near-infrared Polarized Interferometer
XIE Zheng-mao, QI Wen-bo, WU Guo-jun, and HE Jun-hua
Phase compensator is a key element in the polarized interferometer, whose stability has a directive influence on the reliability of the polarized interference spectroscopy. The specification of the phase compensator such as the relative sensitivity of optical path difference, the tilted error tolerance of optical wedge, the oblique incidence angle error tolerance and the temperature adaptability were studied, and the corresponding calculated formulas were derived. The anti-interference ability of the moving optical wedge is 2/Δnsinθ times stronger than the classical Michelson interferometer. The ability of the moving wedge to resist the inclination is 1.75/Δn times higher than classic Michelson interferometer. After light′s incidence with small angle, there are no additional optical path. The greatest optical path distance error of the phase compensator is 1.8 μm when the temperature changes from ―20℃ to 85℃,which has a good thermal stability. The angle of the wedge is also an important parameter to affect the phase compensator. If setting the angle of the wedge as 30°, a good balance between performance, size and cost may be achieved. The birefringence difference of crystal material is smaller than one, so the stability advantages of the polarized interferometer are very obvious which build up a good basis for its field application with complicated surroundings.
Acta Photonica Sinica
  • Publication Date: Sep. 01, 2016
  • Vol. 45 Issue 9 923003 (2016)