Fundamental Characteristics Of Micro-structured Core Photonic Crystal Fibers And Produce Of Dark Hollow Beam

Photonic crystal fiber(PCF) as one of the focus that studied by many people in the photoelectron fields, including the characters,guide-light mechanism and fabrication. PCF is also studied as the focus. This paper designs all kinds of micro-structured core Photonic crystal fibers. Influence of micro-structured core on characteristics of photonic crystal fibers are studied by electromagnetic scattering theory of multipole method at the theory, and produce of dark hollow beam is also studied.Firstly, Photonic crystal fiber(sPCFs)with rectangle core and elliptical core have been designed in this paper. Their fundamental characteristics are studied by electromagnetic scattering theory of multipole method. It is found that the fiber birefringence, dispersion and nonlinear characteristics can be flexibly adjusted by changing the radius of the air holes in the core. The three zero-dispersion-wavelength of elliptical core PCFs locate in visible, near-infrared and mid-infrared band, respectively. For similar structural parameters, elliptical core PCFs are easier to achieve high birefringence and high nonlinear than rectangular core PCFs.Secondly, a high-quality hollow beam is produced through a selectively liquid-filled photonic crystal fiber. A dark spot size of the liquid-filled photonic crystal fiber -generated hollow beam can be tuned by inserting liquid in the cladding region and varying photonic crystal fiber structure parameters. The liquid-filled PCF makes a convenient and flexible tool for the guiding and trapping of atoms and creation of all-fiber optical tweezers. Finally, the application of dark hollow beams in the atomic optics and the other fields are also discussed.Finally, a method by employing circular air-hole in the fibre core was proposed to form micro- structure fibre core photonic crystal fiber. we Study properties of dark hollow beams produced by the micro-structure fiber core photonic crystal fiber by changing the radius of the air holes in the core and filling with medium for a different effective refractive index in the fibre core air-holes. It is found that: the micro-structure fiber can produce good quality of the dark hollow beam with or without center holes, but when the center air-hole exists, we can adjust a dark spot size of the dark hollow beam by changing the radius of the air holes in the core. The further study shows filling with medium for a different effective refractive index in the fibre core air-hole not only can adjust the size of dark spot of the dark hollow beam, but can adjust quality of dark hollow beams. Finally, the application of dark hollow beams in the atomic optics and the other fields are also discussed.