A novel kind of domestic twins fiber that consisted of active unit and passive unit was researched in this paper. The slop efficiency of the twins fiber was observed via various laser amplification testing systems, which were respectively established with two different pump wavelengths and two different numerical apertures of pump output fiber. The effect of both pump wavelength and numerical aperture on the slop efficiency of the twins fiber was analyzed during the experiment. After the laser amplification testing system was optimized, the slop efficiency of the twin fiber increased from 72.1% to 82.1%. The numerical aperture of the pump output fiber would exert a distinct influence on the slop efficiency of the twins fiber. Simultaneously, the method to improve the slop efficiency of the twins fiber and decrease heat generating in high power fiber laser system was suggested.
Polarization maintenance fiber with high birefringence is an important goal for the development of high power fiber lasers. There are different ways to achieve high birefringence, such as change shape of a fiber’s core and apply stress to a fiber’s core. In this paper, fibers with different ovality of elliptical core are fabricated and tested. On the other hand, stress type PM fibers are also made, including PANDA type fibers and bowtie type fibers. Their test results are compared and analyzed together with their structures. Generally, the bowtie type fibers has highest birefringence, while the PANDA fibers are with high birefringence and high production efficiency. Different application can choose different type of PM Laser fibers.