Research On Novel Photonic Crystal Fibers And Key Technologies Towards Their Applications

ABSTRACT:Ever since 1996, photonic crystal fibers (PCFs) have been attracting worldwide interest owing to their unique optical properties and design flexibility. Great progress has been made over the past ten years, and PCFs have been found applicable in a wide range of areas, such as fiber communication, fiber sensor, fiber optics, optoelectronics and so on. Supported by national nature science foundation, national 863 high technology research project and key project of Chinese Ministry of Education, this dissertation is devoted to the theoretical and experimental investigations on novel PCFs and the fabrication and splicing technique of PCFs. The main achievements of this dissertation are listed below:1. A fluid-mechanics model in which the pressure term is included is built for modeling the fabrication of PCFs. The interplays among all the fabrication parameters are numerically analyzed for the purpose of cooperative control. Relationships between parametric configuration and the final fiber's geometry are quantitatively assessed, and are used as guidelines for practical fabricating. With different sets of parameter configuration, several PCFs with different d/A are drawn from a same preform.2. Due to the lack of seperate pressure injection system, a solution for simultaneous control with equal pressure is proposed based on an inverse design model to meet the requirement of maintaining different hole-sizes in PCFs with uneven-sized holes. A variety of PCFs are successfully fabricated consequently, including two-mode PCF, dispersion compensating PCFs, and flattened dispersion PCFs.3. A novel two-mode PCF is designed and fabricated. The holey geometry of the real fiber is extracted using digital image processing method, based on which the properties of the actual PCF can be modeled. The results show that the two-mode PCF supports only the fundamental mode, LP01, and the second-order even mode, LP11 (even), over the wavelength range 500 to 1900nm, which approaches ten times the bandwidth of elliptical-core two-mode fiber. A compact interferometer is constructed based on this two-mode PCF, and stable and sinusoidal transmission spectrum is acquired, exhibiting potentials for fiber sensor and wavelength selective filter applications.4. Based on resonant coupling effect, two kinds of single-polarization single-mode (SPSM) PCF are proposed. Key design points are discussed in detail. Both SPSM PCFs exhibit the advantages of ultrabroad SPSM bandwidth (1000nm or so), Gaussian-like field distribution, and large mode area matchable with conventional single mode fiber over other SPSM fibers reported.5. A universal low-loss arc-fusion scheme for PCF splicing is proposed. Combining experimental measurements with theoretical calculations, the optimal fusion power can be deduced for optimizing the configuration of fusion parameters. Low-loss high-strength splice between PCF and conventional single mode fiber, or between two PCFs can be implemented with the proposed scheme.