摘要： Pulsed lasers operating at mid-infrared (IR) are promising light sources useful for a variety of applications such as eye-safe light detection and ranging (LIDAR), gas detection, and laser surgery. Passive mode-locking technique is commonly used to obtain ultra-short pulses because it has advantages including a simple configuration, and low-cost implementation. In order to induce passive mode-locking within a fiberized cavity, the key element is a saturable absorber (SA). Until now, III-V compound semiconductors based SAs have been widely used. For the past decades, massive investigations to search for alternative SA materials such as carbon nanotubes (CNTs), graphene, topological insulator (TIs), transition metal dichalcogenides (TMDCs), have been conducted all over the world. Skutterudites have received a great amount of technical attention in the field of thermoelectrics due to low-cost, high thermoelectric quality, and long-term thermoelectric stability. The general chemical formula of the common binary skutterudites is TX3, in which T is a group transition metal and X is a pnicogen. Recently, the author’s group have investigated the saturable absorption properties of skutterudites. In this work, we experimentally demonstrate the potential of CoSb3 particles for the implementation of a saturable absorber that can operate as a passive mode-locker in the 1.9 μm wavelength region. The mode-locker was implemented by depositing a CoSb3/polyvinyl-alcohol (PVA) composite film onto the flat surface of a side-polished fiber. Using the prepared saturable absorber, it is shown that stable mode-locked pulses with a temporal width of ~838 fs at a repetition rate of ~16.93 MHz could be readily obtained from a thulium-holmium (Tm-Ho) co-doped fiber ring cavity. The center wavelength and 3-dB bandwidth were measured as 1912.9 nm and 4.62 nm, respectively.