Regular ArticlesDual-wavelength nano-engineered Thulium-doped fiber laser via bending of singlemode-multimode-singlemode fiber structure

•Dual-wavelength fiber laser using nano-engineered Thulium-doped fiber.•The singlemode-multimode-singlemode fiber structure packaging method using Cr-39 plates is illustrated.•The dual-wavelength fiber laser provides narrow spacing of 0.86 nm, spectral linewidth of 0.065 nm and SNR of 42 dB.•Stability test conducted shows very small mode hopping at the two wavelengths.

In this paper, a dual-wavelength fiber laser (DWFL) using nano-engineered Thulium-doped fiber as a gain medium with a bent singlemode-multimode-singlemode fiber structure (SMS) is demonstrated. The SMS structure is packaged systematically using Cr-39 polymer plates to provide linear bending via applied load. Experimental results have proved that the bent SMS is capable to provide highly effective wavelength filter and wavelengths stabilizer by balancing the net cavity gain between the two wavelengths. The DWFL provides very narrow spacing of 0.9 nm, narrow 3 dB spectral linewidth of ∼0.07 nm and SNR of ∼42 dB. Based on stability test, very small mode hopping is observed at the two wavelengths having deviations of ±0 nm and ±0.04 nm respectively. In conjunction, the DWFL provides very stable relative wavelength spacing with a deviation of ±0.04 nm.