Optical fiber transmission has become the predominant mode of transmission in modern communication systems. The extensive bandwidth potential of optical fiber makes it crucial for achieving high-capacity transmission. With the successful development of anhydrous peak fiber, the issue of harmonic absorption caused by OH molecules has been effectively resolved. This novel fiber establishes a low-loss window within the wavelength range from 1280 nm to 1625 nm, thereby providing enhanced transmission capacity for fiber optic communication systems. By increasing WDM density, which involves the simultaneous utilization of multiple light signals with different wavelengths in the fiber, higher transmission capacity can be achieved. This paper presents a comprehensive simulation study on bismuth-doped fiber lasers operating within the 1250-1300nm band. Specifically, this study investigates the numerical relationship between laser power, threshold power, and pump power. The simulation results demonstrate that a threshold power level of approximately 1.5W is required for laser generation; no laser emission occurs below this threshold. Once the pumping power surpasses this threshold value, laser operation commences and output power increases proportionally with further increments in pumping power.