Theoretical And Experimental Studies Of Multiple Asymmetric Optical Fiber And Optical Fiber Grating

With the advent of many types of optical fiber and optical fiber grating, the ability to regulate and control the light waves almost play to the extreme for a single fiber and fiber grating, it seems that people only through complex fiber integrated system for achieving further manipulate light, however, this is clearly contrary to the development trend of miniaturization and integration for fiber optic device. In accordance with the new physical point of view, the meaning of the optical fiber technology in light control and light information exchange also far more in-depth understanding and mining, in-depth research has yet to be carried out from different angles. Therefore, based on the theory of three-dimensional spatial modulation and the grating writing technology by frequency CO2laser pulses, we designed or developed several multiple asymmetric optical fiber and optical fiber grating for the first time, and research and exploration of their application, to provide new ideas and new methods for designing or developing new optical fiber and fiber grating which with the flexibility to manipulate light waves. The main contents and research results are as follows:1. We firstly proposed the concept of multiple non-symmetrical optical fibers and optical fiber grating. According to the spatial modulation characteristics of the optical fiber and fiber grating, we firstly systematic analysis and summary the multiple non-symmetry of the optical fiber and the optical fiber grating, enriching the existing classification of fiber and fiber grating.2. We firstly systematic analysis the performance of the fiber-optic light guide by the multiple non-symmetry. Respectively, how the core asymmetry on the fiber cross section impact on the performance of the fiber-optic light guide; how the clad cladding asymmetry on the fiber cross section impact on the performance of the fiber-optic light guide; how the axial direction asymmetry impact on the performance of the fiber-optic light guide, to theoretical simulation and analysis on the characteristics of the asymmetric optical fiber.3. We populated temperature sensitive refractive index matching fluid in asymmetric region of polarization-maintaining photonic crystal fiber by the selectivity fill method, achieving of common asymmetric filling modulation for the axial direction and cross-sectional of fiber. We developed a new type of temperature sensor by putting the filled photonic crystal fiber in Sagnac loop. We could flexibly regulation of the conduction properties of the light in the photonic crystal fiber by the proposed multiple asymmetric filling method, it provided new ideas and new methods for developing new type photonic crystal fiber tuning device.4. A new type broadband single-polarization single-mode microstructure fiber based on index-matching coupling is proposed by using the full vector finite-element method. The single-polarization single-mode operation bandwidth reaches400nm. The fiber has a flexible regulation of the core mode and more local cladding mode coupling coefficient. The proposed design method has an important reference value for designing and developing the new microstructure fiber.5. We firstly proposed a dual-band orthogonal single polarization single-core microstructure fiber. The light located in the1.31-and1.55-μm bands propagates through orthogonal polarization states in the proposed fiber. For a propagation distance of20mm, the20-dB bandwidth for the same x-or y-polarized modes within the1.31-and1.55-μm wavelength bands could, respectively, reach20.5and45.3nm, which is much wider than that of a two-core PCF.6. Based on the finite difference beam propagation method, we designed a multiple a tunable fiber coupler with the asymmetric structure. The operating wavelength of such a coupler can be adjusted in1.40μm to1.70μm band, and the output splitting ratio of the coupler can be adjusted at any wavelength. In addition, the designed optical-fiber coupler is integrated in a fiber with only7.3mm length. This provides a new idea for the all-fiber optical and miniaturization devices.7. A novel bending vector sensor based on spatial cascaded orthogonal long period fiber gratings (SCO-LPFGs) written by high-frequency CO2laser pulses has been proposed, and two-dimensional bending vector sensing characteristics based on the simple SCO-LPFGs have been experimentally demonstrated. A three- dimensional orthogonal sensing coordinates is established, and furthermore both of curvature and bending-direction could be intuitively solved according to the coordinates. To some extent, these studies would be improve the practicability of fiber vector sensor due to its simple, low-cost, ease of fabrication, and simple, precise, intuitive interrogation method.8. We analyzed the spatial modulation characteristics of multiple asymmetric tilt long period fiber grating, established the theoretical analysis model. Experimental study the twist sensing characteristics of tilt long period fiber grating and tilt Ultra-long period fiber grating. The results show that, tilt long period fiber grating can be used to the new twist and temperature two-parameter sensor.9. We designed several asymmetric double eccentric and center-side double cores fiber-based multiple asymmetric fiber grating. We combined of fiber multiple asymmetric spatial modulation and fiber grating multiple asymmetric spatial modulation characteristics, and analysis and explore its potential application. It has the extremely important reference value for designing and developing the new functional integration fiber grating.