Study of Cr4+:YAG Double-clad Fiber ASE
Date Issued
2009
Date
2009
Author(s)
Yang, Mu-Han
Abstract
Optical coherence tomography (OCT) will play an important role in the future due to the high resolution, real time imaging, and the noninvasive detection for human cell. There are many light sources beam applied to OCT such as superluminescent diode, mode-locked Ti:sapphire laser, LED, thermal tungsten halogen lamp, ect. Because of the broadband spectrum, all these sources have high axial resolution. Take image quality into account, the spectrum shape is an important factor. Some of these light sources suffer from poor image due to the side lobe of the point spread function. In addition, higher signal to noise ratio can support better image quality. To achieve higher signal to noise ratio, one way is to reduce the noise, and another way is to enhance the light source power. In this thesis, we report the fabrication of Cr4+:YAG double cladding fiber as the broadband light source for OCT. The bandwidth of Cr4+:YAG double cladding fiber is about 245 nm, the axial resolution for OCT system is 3.6 μm. We also optimize the output of ASE by dual pump set and ASE HR coating on the endface of fiber, in order to enhance the signal to noise ratio. A total output power of 3.15 mW was achieved. In addition, in this thesis, we discuss the polarization effect of pump light on ASE. We have also fabricated Ti:Sapphire double cladding fiber. So far, we can fabricate double cladding fiber with 48 μm core size. The bandwidth of ASE is 164 nm, which can be used for OCT with an axial resolution of 1.56 μm.
Subjects
optical coherence tomography
Cr4+:YAG double-clad fiber
broadband light source
Ti:sapphire
crystal fiber
dual pump
Type
thesis
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