Coupling between Ultra High-Power Laser Diodes and Fibers

• Main Authors: Kuo-liang Wang, 王國良
• Other Authors: Wood-hi Cheng
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/49760258446739394426

碩士 === 國立中山大學 === 光電工程研究所 === 93 === The width of an ultra high-power laser diode is greater than 50 μm and more than 20 times of low-power laser diode.The core diameter of Erbium Doped Fiber Amplifier fiber (EDFA) is 4~6 μm and it is a single-mode fiber (SMF).However，the ultra high-power laser diode is multi-mode laser. Therefore，the mismatch between high-power laser and SMF resulting in low coupling efficiency. We improve coupling efficiency by using a wedge-shaped graded-index fiber (GIF) tip spliced to a SMF then fused a fiber bragg grating (FBG) to form an external cavity laser. The GIF is a focusing action like a graded-index fiber. From near-field pattern (NFP)，we find the best GIF length is 400 μm. The coupling efficiency between ultra high-power laser diode and wedge-shape lensed fiber is only 5% .