We report a linearly-polarized 1617 nm Er:YAG laser pumped by 1532 nm fiber-coupled laser diodes. An L-shaped resonator was employed incorporating two Er:YAG crystals which were pumped independently. In continuous-wave operation, a maximum output power of 7.73 W was obtained with an optical conversion efficiency of ~15.2% (versus incident pump power). To the best of our knowledge, this was the highest conversion efficiency ever demonstrated for a directly diode-pumped Er:YAG laser. In Q-switched operation, pulses with energy of 7.8 mJ and pulse duration of 80 ns were yielded at a repetition rate of 500 Hz, and the corresponding peak power was ~ 97 kW at 1617 nm.
An all-fiber high modulation speed pseudorandom-coded laser based on master oscillator power amplifier configuration is proposed. We use a high modulation rate distributed feedback laser diode as the seed laser to generate the original pseudorandom pulse train. The modulation rate is 1 Gb/s , which corresponds to a minimum pulse interval of 1 ns. A 1 kHz repetition frequency of 10-order M -sequence pseudorandom pulse train is chosen to balance on-line data processing speed and laser ranging resolution. Then, the pseudorandom pulse train is amplified by two-stage amplifiers to boost the output power. All components used in the amplifiers are built in single mode (SM) fiber, so the final output laser is SM with excellent beam quality. Finally, the peak power of pseudorandom code laser is amplified to 23.6 W from 1.5 mW without wave distortion, corresponding to a gain of 42 dB. The ranging experiment of using the optical fiber delay method indoors shows the transmitter of combining modulated laser diode and multistage fiber amplifiers as a promising solution for developing laser for pseudorandom-coded laser ranging.
Thermal heating is a major limiting factor in scaling the average power of a solid-state laser. In this paper some primary factors which affect the thermal effects of the typical side-pumped and side-cooled slab laser are discussed. The temperature and stress distribution in the cross-section in the laser crystal are calculated by using FEA. Some conclusions which optimize the performance of the side-pumped and side-cooled laser are drawn.