Fabrication and Measurement of Single-mode Crystal Fiber Broadband Light Sources
Date Issued
2010
Date
2010
Author(s)
Liao, Yi-Han
Abstract
We successfully fabricated Cr4+:YAG double-clad crystal fibers with co-drawing laser heated pedestal growth method to achieve 10-um-core Cr4+:YAG double-clad crystal fiber. This is a multimode fiber due to the high refractive index difference between the core and the inner-clad. In this study, TiO2 side-deposition method and high-index-glass capillary were used to reduce the index difference.
Via the sputter method, the TiO2 thin film was coated on the Cr4+:YAG single crystal fiber. To observe double-clad crystal fiber, the refractive index of inner-clad near the interface between the core and the inner-clad was increased from 1.66 to 1.74.
Utilizing the SF57 high-index-glass as the surrounding material to fabricate the Cr4+:YAG single-clad crystal fiber, the refractive index difference is about 0.007. The corresponding numerical aperture of the crystal fiber is 0.16, and it is very close to the conventional single-mode fiber. Furthermore, the V-value (normalized frequency) is 14.35 and the propagation mode number of SF57-clad Cr4+:YAG single-clad crystal fiber is 42 for the 40-μm-core diameter.
Besides, we successfully fabricated the Ti:sapphire crystal fiber by means of laser heated pedestal growth method to generate broadband amplified spontaneous emission centered at 760 nm with 180 nm bandwidth and 875 μW power pumped by a 532-nm laser. On the other hand, 100 μW output power of this crystal fiber pumped by 446-nm diode laser was also demonstrated. Using this broadband fluorescence as the optical coherence tomography light source, -26.1 dB 1st and -43.4 dB 2nd cross talk factors with 1.44-um-axial resolution were calculated.
Subjects
OCT
crystal fiber
LHPG
single-mode
side-deposition
high-index-glass caplliary
Type
thesis
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