Dual-wavelength random fiber laser incorporating micro-air cavity

A dual-wavelength random distributed feedback fiber laser with external micro-air cavity (MAC) is experimentally demonstrated. The structure that comprises of a fixed 200 mu m air-gap distance between two flat-angle fiber-end facets behaves similarly to the role of reflectors. The generation of dual-wavelength lasing at 1552.5 and 1557.7 nm was achieved. The accomplishment is associated to the filtering effect of MAC superimposed with Raman gain spectrum. Equal peak power of approximately -12.7 dBm was attained at maximum 2.0 W pump power. In this case, the respective optical signal-to-noise ratios were 18.79 and 18.73 dB. Excellent stability of the spectral width was realized over 60 min observation time at room temperature, which denotes the practicality of this device in addition to the relatively simpler architecture.