Microfiber-Based Polarization Beam Splitter and Its Application For Passively Mode-Locked All-Fiber Laser

Nonlinear polarization evolution based on polarization beam splitter (PBS) is a classical technique for passive modelocking of fiber lasers. Different from commonly used bulky PBS, in this paper all-fiber PBSs composed of two parallel coupled microfibers have been proposed and fabricated under the condition of appropriate microfiber diameter and coupling length. Using our fabricated microfiber PBSs, passively mode-locked all-fiber lasers have also been demonstrated. The results indicate that the microfiber-based PBS has advantages of simple fabrication, compact size, and most importantly, variable polarization extinction ratio and operation bandwidth. The all-fiber mode-locked lasers with the microfiber PBSs generating stable pulses at both 1.0 mu m and 1.5 mu m wavelength bands have comparable performance with their counterparts based on bulky PBSs. It may be a step towards true all-fiber mode-locked laser and other all-fiber systems.

Automated summary

This paper proposes and fabricates all-fiber PBS, demonstrates passively mode-locked fiber lasers using this technology, and finds that it has advantages of simple fabrication, compact size, variable polarization extinction ratio, and operation bandwidth. Compared to traditional PBS, all-fiber mode-locked lasers with microfiber PBSs exhibit stable performance, showing potential towards true all-fiber mode-locked lasers.