The Research Aboat The Infrared Optical Fiber Laser And Waveguide Photodetector

There is a strong interest in the development of mid-IR lasers （2-5μm） mainlybecause of their potential applications in medical, military defence, laser ranging, tele-communications, gas detection and molecular spectroscopy. Medical applications oflasers depend on the interaction of light with biological tissue. Mid-IR lasers have largeabsorption coefficients in water and can generate substantial heating in the tissuesufficient enough to break the chemical bonds, making them effective cutting tools andalso cauterizing incisions in the process. In addition, compact and efficient pulsedmid-IR lasers can serve advantageously for target designator, remote light detection,laser ranging （LIDAR） and optical tele-communications applications owing to the hightransparency atmospheric windows in3-5μm. On the other hand, the waveguidephotodetector can overcome the quantum efficiency limit and background noise oftraditional PIN photodiodes, also has showed great attraction. In this dissertation, themain research contents of Mid-IR fibre lase and waveguide photodectors are as follows:1. Based on the core pumped and cladding pumped cascaded Ho³⁺-doped, Ho³⁺,Pr³⁺-co-doped and singly Ho³⁺-doped fluoride fiber lasers, their correspondingnumerical modeling are constructed. Using the measured energy-transfer （ET）,energy-transfer-upconversion （ETU） and cross-section parameters, the accuracy of themodel is verified by good agreement with experimental results from a number ofpreviously reported Ho³⁺-doped fluoride fiber lasers. The model is then used to analyzethe bottlenecking mitigation schemes and important interionic processes affecting thelaser performance for each system.2. A high-power diode-cladding-pumped fiber laser operating in the mid-infrared isdemonstrated. The Ho³⁺-doped fluoride glass fibre laser produced a maximum outputpower of0.77W at a slope efficiency of12.4%and the wavelength was3.002μm whichindicates the first watt-level fibre laser operating in the mid-infrared.Then, a doubletuning mid-IR Q-switched Ho³⁺-doped ZBLAN fiber laser is demonstrated.The tuningregion was from2.95μm to3.031μm, and the output wavelength of which was over3μm. In addition, a pluse train was generated from5I6â†'5I7laser transition. 3. Based on the3D-BPM model, computed the effective refraction index, energytransfer of a diluted waveguide. By using FIMMPROP software, we designed a wholediluted waveguide detector, and optimized the structure of fibre-waveguide,coupling-waveguide and active region.