We investigated various types of optical fiber sensor based on novel structure of photonic crystal fibers (PCFs) including Ge-doped ring defect PCF and Suspended ring core PCF. Furthermore, a new type of fiber named C-type fiber is utilized as a fiberized sensor unit in/outlet. This configuration enabled to package the entire sensor unit in fiber form as well as could overcome prior limitations in PCF-based optical sensors such as too small holes for efficient measurand entry and sophisticated fabrication processes. The experiment and simulation results proved that the designed sensor can improve both sensitivity and response time compare to conventional PCF based sensors.
We report development of a new kind of micro-optical waveguide based on liquid core in a V-groove glass and air cladding and a similar finite element method was constructed to investigate the guiding properties such as mode distribution and modal birefringence. Through the detailed modeling, we investigate the role of each parameter such as, refractive index of core and diameter of core of V-groove structure. This work demonstrates numerically and experimentally high birefringence in this optical waveguide and different aspects of the fiber properties related to the fundamental mode and fiber birefringence are revealed. As a result, wave-guide with large birefringence is identified for opening angle of 40 degree and refractive index of 1.472.
The in-line chemical sensing device with novel C-type fiber and photonic crystal fiber was successfully fabricated. We
further improved the sensitivity or light coupling efficiency of our in-line chemical sensing device with optimized the Ctype
fiber length. The results show that sensitivity and response time of device are significantly enhanced with
optimization of cleaving and splicing process. The gas sensing experiments with the optimized conditions are
demonstrated for detecting partial pressure of acetylene. We also numerically analyzed the sensitivity of ring-core defect
photonic crystal fiber which was used in this experiment, through full-vectorial finite element method.
The opacity of some low Z plasmas that are in local thermodynamic equilibrium (LTE) was calculated numerically. In
this study spectrally resolved opacities under different temperature and density plasma conditions was calculated. The
calculation results show that by increasing of plasma density, the opacity can be significantly enhanced. It is also shown
that the plasma opacity increase with rising the plasma temperature reaches to a maximum value and then decreases
again with the plasma temperature.