Switchable and compact dual-wavelength random fiber laser based on random Bragg grating array

A switchable dual-wavelength random fiber laser (DW-RFL) with compact structure and a low-threshold is demonstrated. A Fabry-Perot interferometer which consists of a pair of fiber Bragg gratings is used in the DW-RFL as a filter to select two lasing wavelengths. The random Bragg grating array (RBGA), instead of long-distance single mode fiber, is used to introduce random distributed feedback. The threshold is reduced and the stabil -ity is improved due to the RBGA with high random feedback efficiency and a section of high gain of the erbium-doped fiber. Wavelength selecting and switching can be realized by tuning the pump power. The principle of RBGA and FBG-based F-P interferometer in the DW-RFL is analyzed and simulated. The experimental results show that the lasing threshold is about 18 mW and the optical signal noise ratio is about 40 dB. The stable dual-wavelength oscillation with uniform amplitude is realized. The wavelength spacing of the two lasing lines is within 0.095 nm and the maximum peak-power fluctuation is less than 1 dB. The proposed switchable and stable DW-RFL can be employed in microwave or terahertz generation systems, optical sensing, coherent communi-cation and high resolution measurements.

Automated summary

This study demonstrates a switchable dual-wavelength random fiber laser (DW-RFL) with a compact structure and a low-threshold. A Fabry-Perot interferometer consisting of a pair of fiber Bragg gratings is used as a filter in the DW-RFL to select two lasing wavelengths. By utilizing a random Bragg grating array (RBGA) instead of long-distance single mode fiber, the threshold is reduced and the stability is improved. Wavelength selection and switching can be achieved by tuning the pump power. The proposed DW-RFL has potential applications in microwave or terahertz generation systems, optical sensing, coherent communication, and high-resolution measurements.