Mode-Locked Tm–Ho-Codoped Fiber Laser at 2.06 $\mu$ m

A mode-locked Tm-Ho-codoped fiber laser is reported, which is the first demonstration of a mode-locked fiber laser oscillator at the wavelength beyond 2 μm . The laser was built with a piece of newly developed Tm-Ho-codoped dc silicate fiber and a Sb-based semiconductor saturable absorber mirror (SESAM). When cladding pumped with a laser diode at 0.8 μm, the fiber laser generates mode-locked solitons at 2.06 μm with a pulse energy of 0.41 nJ and pulse duration of 1.1 ps.