Over 252 mW Circularly Polarized Vortex Fiber Laser with Intracavity Tunable Helicity and Chirality via a High-Gain and High-Birefringent Active Fiber

The orbital angular momentum (OAM) intrinsically carried by vortex beams provides additional degrees of freedom for communication and manipulation in both classical and quantum optics. Developing a tunable circularly polarized (CP)-OAM laser source could address the growing demand for high information capacity and enhance the stability of beam transmission. Traditional techniques for generating vortex beams in free space like spatial light modulators and spiral phase plates are usually affected by the diffraction effect, and it is difficult to align different optical components, limiting the practical applications of vortex beams. In this paper, we propose an all-fiber method to demonstrate an intracavity vortex-optics oscillation fiber laser with controllable chirality and helicity. Specifically, we utilize a twisted high-gain and high-birefringent active fiber to directly generate a CP-OAM beam at a telecommunication band in the laser system. Furthermore, two few-mode passive and active spun fibers are employed to maintain stable transmission and amplification of the CP OAM. The results indicate that the CP-OAM lasing emission accomplished has high power with high purity and stability. The intracavity CP-OAM oscillating laser is reported for the first time, to the best of our knowledge, and the output power is as high as 252 mW. As an all-fiber vortex source, this laser with high tunability and integration has great potential to be developed as a versatile vortex device for related applications like ultrahigh-resolution imaging, ultrahigh-precision detection, ultrafine laser processing, and quantum communications.