Research On LD Pumped 1.5?m Miniature Solid State Laser

Wavelength of 1.5?m passively Q-switched solid-state lasers have small size, low cost, simple structure, good beam quality, eye-safe and other advantages. They output nanosecond pulse laser, the laser can be widely used in laser ranging, optical communications, optical sensing, medical treatment and so on. It has significance to study 1.5?m LD-pumped erbium ytterbium co-doped phosphate glass of passive Q-switched laser. In this paper, LD end-pumped erbium-ytterbium co-doped phosphate glass by passively Q-switched to get the pulse of the laser output of 1.5?m. By theoretical and experimental research on the laser, we achieve its practicability. The main research contents of paper are as follows.1?At first,we analyze the Er3+/Yb3+ co-doped phosphate glass luminescent properties. Based on the conversion effect, we amend the rate equation of Er3+/Yb3+ co-doped phosphate glass. The optical field distribution assumes by flattened approximation and Gaussian approximation to discuss the conversion effect on the laser output, and experimental verification.2?We analyze parameters of impacting 1.5?m LD pumped passively Q-switched laser output energy and width. According to Degnan passively Q theory, we get the optimum range of output mirror transmittance, gain medium length, and the pump beam radius when the laser has maximum pulse energy. These provide effective date for optimization experiments.3?The selection method of focusing lens is given by ZEMAX optical simulation software. We obtain the pump spot radius, depth of focus, focal spot position from the pump source at different focal lengths by ZEMAX. We obtain the lens focal length range in experiments combine with passive-Q theory. Pumping spot position and depth of focus, they provide a gain media placement and tuning range, saving time in adjusting the optical path of optimization experiments.4?Based on the theoretical analysis, different lens focal length, the length of the gain medium, output mirror reflectivity are experimentally optimized in order to obtain the best energy, getting the various parameters of the laser. Ultimately, we get a laser output single pulse energy is 132?J, pulse width is 6ns, peak power is more than 20 kW, optical conversion efficiency is 1.5%. Laser center wavelength is 1535 nm, linewidth is less than 0.02 nm, M2 beam quality factor is about 1.3, the instability of the laser output is less than 4%.5?We research and realize the gain medium and the passively Q crystal bonding. The overall structure of the laser is designed to ensure the machine is easy to install. And the laser temperature adaptability is tested. At last we obtain practical engineering highly reliable miniaturized eye-safe laser.