The Study Of High-gain Coefficient Yb³⁺-doped Laser Glass

In recent years, Ultra-short-pulse laser, as an important laser source, has increasingly become the subjects of physics, optoelectronics, chemistry, and laser spectrography in studing the microstructure and new ultra-fast processes. In the field of laser material, with the characteristics of easily made of the large size, high uniformity and high light transmittance,etc, especially it can be made high power laser, the glass has become a focus for researchers. Yb3+doped laser material is a new candidate for the ultra-short pulse laser application because of its broad fluorescent spectrum and high quantum efficiency. But the defects of the present Yb3+doped phosphate and silicate glasses for ultra-short-pulse laser are their sharp gain profile, longer pulse and relatively lower ultra-short-pulse output power. It is valuable to explore new Yb3+doped glass matrix for realizing high-power ultra-short-pulse laser.At the same time, the development of laser glass is also driving the research and progress of the optical fiber.With the birth of photonic crystal fiber, people start trying to the combination of Yb3+-doped glass medium with photonic crystal fibers because of its superior optical properties, which will be the ideal medium for the preparation of ultra-high-power lasers.Based on the above two aspects, the research and exploration work are carried out, mainly research of the thesis are as following:1. The choice of system components of the Yb3+-doped laser glass was discussed, a series of different formulations of Yb3+-doped fluorophosphates glass were melted with the fluoride phosphate glass being as a substrate. By optimizing the formulation and test performance, glass samples with stimulated emission cross section1.62pm2, the fluorescence lifetime1.65ms, and thus gain coefficient2.67were prepared, which is an ideal material for the achievement of high-power ultra-short-pulse laser, and also a good mandrel material of photonic crystal fiber.2. Two kinds of HB-PCFs are designed in this chapter. One is a single defect structure with four large air-holes in the cladding near the core with the other air-holes are elliptical ones, while the other is a double defect structure with six air-holes near the core. The dispersion results show that large air-holes near the core can sufficiently enhance the value of the birefringence. The HB-PCFs with four holes structure has the larger x polarized mode dispersion, which indicates it can be used in single polarized mode dispersion compensation.