Research On Characteristics Of A Novel Terahertz Plastic Photonic Crystal Fiber

There are very important scientific and application values for the terahertz (THz) waves which have unusual regions and superior characteristics. At present, THz waves are mainly based on free space transmission. To guide THz waves over long distance with low loss and low dispersion, it is still a difficult task for researchers. Photonic crystal fibers(PCF) which have various excellent characteristics and broad application prospects are hotspot in the fiber fields, on the other hand, lots of plastic materials'absorption loss is very low in THz area .Because of these, they offer the opportunity to create new means of THz plastic PCFs .A new type of THz plastic PCF, whose claddings are made of polythene (PE) containing periodic circular teflon holes and core organic material is teflon(PTFE), is proposed. Band-gap distribution characteristics of this THz plastic PCF and how teflon -filling factors affect the band-gap distribution characteristics are investigated by plane wave method (PWM).Then dispersion characteristics and loss characteristics of the THz plastic PCF with different parameters are respectively computed by finite-difference time-domain method (FDTD) and finite-difference frequency-domain method (FDFD). The results show that THz plastic PCF with low dispersion and low loss can be achieved through optimizing three geometrical parameters , two for teflon -hole diameters and one for hole pitch. The new THz plastic PCF can have the almost flattened dispersion on the value ? 0. 5ps /(km?nm),the lowest loss on the value 2.6dB/km from 46? m ? 54?m wavelength. Numerical results show that this plastic PCF is a sort of photonic band-gap guiding fibers with good capabilities to transmit terahertz waves. Compared to PCFs which apply on optical bands, THz plastic PCFs take apparent advantages on production costs and processes.According to the possible types of defects in the production practice, how the defects affect on the characteristics of THz plastic PCF is studied. The results show that missing and mismatch of cladding lattice will both cause some bad influence, such as narrowing of band-gap, movement of zero dispersion point, addition of loss and so on. However, the missing of cladding lattice will more or less lead the dispersion curves to become more flat. All these will contribute to further development of THz devices and faster processes of commercialization.