(1) Improvement of fiber laser performance: How to improve output power and conversion efficiency, optimize beam quality, shorten gain fiber length, improve system stability and make it smaller and more compact are the focus of future research in the field of fiber lasers.
(2) Development of a new type of fiber laser: In the time domain, ultrashort pulse mode-locked fiber lasers with a smaller duty cycle have always been a hot spot in the laser field, and high-power femtosecond pulse fiber lasers have been a long-term pursuit. The goal. In the frequency domain, broadband output and tunable fiber lasers will become a research hotspot.
The research of fiber lasers has been started since the late 1980s. Because of its ability to generate ultrashort pulses and have very broad application prospects, countries around the world have shown great enthusiasm for fiber laser research. Compared with other types of lasers, fiber lasers have outstanding advantages such as high reliability, simple structure, low price, and high conversion efficiency.
Domestic research in this field has also been carried out relatively early, and a lot of research results have been obtained both theoretically and experimentally. However, compared with foreign countries, there is still a big gap. In particular, there are relatively few researches on high-performance fiber lasers, and the work done in practical aspects is far from enough, and the effect is not very satisfactory. Therefore, it is necessary to further strengthen the research on passively mode-locked fiber lasers.
In 1963, Snitzer reported for the first time a fiber laser doped with Nd, 10, and the upsurge in the study of fiber lasers has since started. Especially in recent years, with the progress made in the design and manufacture of optical fibers, the output of fiber lasers has continued to increase, and the CW output power of a single optical fiber device has risen from the hundreds of watts to the kilowatts. At the same time, the improvement in manufacturing technology of high-quality optical fiber with large cladding diameter and large numerical aperture makes it easy to achieve effective coupling with the pump power of the diode.
The most significant advantage of fiber lasers is their extremely high pumping efficiency. In general, the pump conversion efficiency is 70%-75%, which is much higher than that of industrial diode pumped solid-state lasers (DPSSL). Such a high conversion efficiency reduces the cooling and power requirements of the laser system, and can be more compact than traditional solid-state lasers. In addition, the all-fiber structure can provide a very robust and highly reliable package design. Moreover, fiber lasers can significantly enhance the output beam quality.
Another important advantage is that fiber laser technology can greatly extend the life of the device (compared to DPSSL). This advantage has caused industrial laser companies that pay attention to fiber lasers to increase their investment, because the long-term reliability of the application is very important. important. Fiber lasers also have other advantages: Since the laser medium of the fiber laser is a guided wave medium, the combination efficiency is high; the fiber laser can be easily connected with the fiber transmission system and efficiently; the fiber core can be made very thin, which can achieve high power density; The heat dissipation performance of the fiber is good, so the fiber laser has a high conversion efficiency and a very low threshold; the output wavelength of the fiber laser covers a very wide range, from 400 to 3400nm, which can meet the needs of various applications. Military, medical and other aspects have very good application prospects.
