| Summary: | 碩士 === 正修科技大學 === 電子工程研究所 === 100 === Due to the fast expansion and development of the optical communication industry, the demand of the broad-band laser light sources used as the optical transmission network system has correspondingly extremely increased. Cr4+ doped yttrium aluminum garnet (YAG) has a strong spontaneous emission (ASE) that can generate the wavelength of near-infrared emission from 1200 to 1600 nm. This broadband emission has aroused great interest in developing tunable wavelength lasers, ASEs and optical coherent tomography (OCT).
There are two major contributions of the thesis. First, we have successfully analyzed the strains in Cr:YAG double-clad crystal fibers (DCF) with CaO perimeter deposition under high temperature oxygen annealing treatment. For the original Cr:YAG DCF without CaO deposition and annealing treatment, there exist a nearly zero strain cross the entire 20-m core diameter.. The compressive strain nearby the interface of core/inner-cladding can be generated by CaO perimeter deposition or high temperature annealing treatment.
The single-mode crystal fiber has the higher efficiency resolution. It is the favorable factor of OCT. The second point is the study of single-mode crystal fiber fabrication using Cu in-diffusion. The experimental results show that the Cr4+ fluorescence intensity and the diameter of crystal fiber can be reduced by Cu in-diffusion after re-growth. The refraction index of Cu,Cr:YAG crystal fiber will be reduced from core center to the edge under annealling at 1200 oC with above 8 hours. The total reflection of refraction index distribution in the YAG may have applications in optical fiber communications. According to the distribution of of Cr3+ and Cr4+ fluorescence intensities, the depression of Cr4+ can be illustrated.
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