Multiwavelength all-fiber ring laser using side-polished fiber comb filter and mechanically formed long-period fiber gratings

Multiwavelength all-fiber lasers to be operated at room temperature are demonstrated. A side-polished fiber comb filter and mechanically formed long-period fiber gratings (LPFGs) are used to generate colasing operation. By using the band suppression characteristics of the LPFGs to prevent the gain cross-saturation effect, simultaneous lasing of four-wavelength peaks is obtained.