Demonstration of Multiwavelength Erbium-Doped Fiber Laser Based on a Microfiber Knot Resonator

We proposed and demonstrated a stable multiwavelength erbium-doped fiber laser by using a microfiber knot resonator (MKR)-based comb filter. By properly rotating the polarization controller, up to 11 lasing lines in a 3-dB bandwidth with 0.184-nm channel spacing were obtained. In addition, the lasing locations can be flexibly tuned by virtue of spectral filtering effect induced by the polarization-dependent isolator and the intracavity birefringence. The results demonstrated that the MKR could be employed as a high performance comb filter to realize a compact multiwavelength fiber laser.