Ultra-broadband tunable and switchable multi-wavelength mode-locking Tm-doped all-fiber laser

Abstract Through regulating the in-band absorption of used gain fiber, we demonstrate an ultra-broadband tunable and switchable multi-wavelength mode-locking Tm-doped all-fiber laser. The tuning range can be enlarged as much as 153 nm (from 1828.45 to 1981.35 nm, the largest tuning range so far) by employing different lengths of used gain fiber with different in-band absorption and birefringent filtering mechanism. In addition, benefiting from four in-line polarization controllers and broadband gain profile of Tm-doped fiber, switchable quad-wavelength mode locking with part binary control can be observed clearly, even penta-wavelength. Such kind of ultra-broadband tunable and switchable mode-locking laser provide simpler and elastic way for practical application, such as optical signal processing, spectroscopy, optical communications, and so on.