1：Experimental Design and Method Selection:

The experiment involves a simple approach combining a 15-cm-long Ho:ZBLAN fiber pumped by a blue LD at ~450 nm, and a pair of fiber end-facet mirrors for direct green lasing. An un-pumped section of Ho:ZBLAN fiber is used for initiating the pulsed operation.

2：Sample Selection and Data Sources:

A piece of 15-cm Ho:ZBLAN fiber (core/cladding:

3：5/125 μm, NA:

4：23, Ho3+:

5000 ppm) was used as the gain medium.

5：List of Experimental Equipment and Materials:

The pump source is based on a homemade ~

6：36 W, 450 nm fiber-coupled LD. A coupled system characterized by two plano-convex lenses (Thorlabs) and a micro-objective lens (#04OAS008, CVI Laser Optics) was used to collimate and focus the blue light to a 1060-XP fiber (core/cladding:

7：8/125 μm, NA:

0.14).

8：14). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The Ho:ZBLAN fiber not only acts as a gain medium but also works as a saturable absorber (SA). The modulation mechanism is induced by the ground-state reabsorption effect in an ineffectively pumped section of the active fiber.

9：Data Analysis Methods:

The output power as a function of the incident pump power was measured using a power meter (Coherent PM3). The output pulse evolution between the self-pulsing state and the self-Q-switching state along with the incident pump power was also measured.