| Abstract：Polarization characteristics of photonic crystal fibers (PCFs) have beenanalyzed and various applications based on polarization characteristics of PCFs havebeen proposed in this thesis. Polarization characteristics of highly birefringentphotonic crystal fibers (HiBi-PCFs), CO2laser side-irradiated PCFs and partiallyliquid-filled PCFs have been analyzed in theoretically, and applications, such as fibersensors and fiber polarizers, based on HiBi-PCFs, CO2laser side-irradiated PCFs andpartially liquid-filled PCFs have been demonstrated in experimentally.1. Based on polarization characteristics of HiBi-PCFs, the HiBi-PCF as asensing head is usually inserted into a fiber loop mirror (FLM). A highly sensitivitytemperature sensor based on a FLM made of an alcohol-filled HiBi-PCF is proposedfirstly. By monitoring one resonant wavelength of the FLM depending ontemperature, the temperature sensitivity as high as6.6nm/°C is realized by using a6.1cm alcohol-filled HiBi-PCF as a sensing header inserted in a FLM. A strainsensor based on a FLM consisted of a7.95cm HiBi-PCF is demonstrated by intensitymeasurement. Intensity measurement is used to monitor the shift on the transmissionspectrum of the FLM caused by strain applied on the HiBi-PCF. The proposed strainsensor based on intensity measurement reduces cost by using power meter, and has ahigh strain sensitivity.2. Polarization characteristics of solid-core PCFs and hollow-core PCFspost-processed by CO2laser side-irradiating are investigated in theoretically. Theconfinement losses of x-polarization and y-polarization, the effective refractive indexand the polarization dependence loss for solid-core PCFs and hollow-core PCFspost-processed by CO2laser side-irradiating have been calculated and analyzed. As aresult, hollow-core PCFs are preferred to fabricate PCF polarizers, becausehollow-core PCFs post-processed by CO2laser side-irradiating have a higherpolarization dependence loss than that of solid-core PCFs. The systematical analysison the polarization characteristics of hollow-core PCFs and solid-core PCFs can be a guidance on fabrication of long period gratings and fiber devices on PCFs by CO2laser.3. Based on polarization characteristics of partially liquid-filled PCF, anovel polarizer based on partially liquid-filled PCF has been proposed firstly.The partially liquid-filled PCF polarizer is optimized on the liquid-fillingregion for a better performance in theoretically. By utilizing a large off-setsplicing to realize the partially liquid-filling on PCF, a6mm partiallyliquid-filled PCF polarizer with a high polarization ration18dB isdemonstrated in experimentally. |
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