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The Study and Fabrication of Optical Thin Film on Cr4+:YAG Double-clad Crystal Fiber Based Devices

Recently, with the escalating demands for optical communications, the need for bandwidth in optical communication network has increased. The technology breakthrough in dry fiber fabrication opens the possibility for fiber bandwidth from 1.3 to 1.6 £gm. Cr4+:YAG double-clad crystal fiber (DCF) grown by the co-drawing laser-heated pedestal growth method has a strong spontaneous emission spectrum from 1.3 to 1.6 £gm. Such fiber is, therefore, eminently suitable for broadband optical amplifier, amplifier spontaneous emission (ASE) light source, tunable solid-state laser, and optical coherence tomography (OCT) applications.
In this thesis, multilayer dielectric thin films were directly deposited by E-gun coating onto the end faces of the heterostructure Cr4+:YAG DCF. In this way we have successfully improved the extracted ASE power by the high reflection (HR) coatings. The backward ASE in the fiber reflected and propagates with gain through the fiber in the forward direction. In dual-pump scheme, as much as 1.7 mW power (DCF length is 9.5 cm) of collimated output ASE was achieved. The dual-pump scheme and HR thin films provided 1.6 time improvements of the ASE output power. For broadband optical amplifier in dual-pump and double-pass scheme, a 3.7-dB gross gain and a 0.7-dB net loss (DCF length is 8.7 cm) at 1.4-£gm signal wavelength have been successfully developed with HR coatings onto one of the Cr4+:YAG DCF end faces. In addition, we have successfully developed the Cr4+:YAG DCF fiber laser by direct HR coatings onto fiber end faces. A record-low threshold of 96 mW (DCF length is 1.6 cm) with a slope efficiency of 6.9% was achieved at room temperature. It is more than four times lower than any previously reported Cr4+:YAG lasers.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0721109-143322
Date21 July 2009
CreatorsLin, Si-rong
ContributorsJui-Yun Yi, Cheng-Nan Tsai, Yen-Sheng Lin, Sheng-Lung Huang, Wood-hi Cheng
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0721109-143322
Rightsnot_available, Copyright information available at source archive

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