To extend the operational range of the fiber grating sensing system into the near-infrared band accessible to silicon-based detectors, this study applies a phase mask to the 1 550 nm waveband for second-order Bragg grating inscription research on the 780 nm waveband. First, the formation mechanism of the second-order grating is analyzed, and then a grating-inscribing system is integrated with an ultraviolet laser equipped with a phase mask grating to fabricate the second-order FBG. The ratio of the first-order wavelength to the second-order wavelength was found to be 1.98, and the bandwidth of the second-order wavelength is narrower. The results indicate that the temperature and strain sensitivities of the second-order grating are 5.28 pm/℃ and 0.65 pm/με, respectively, or approximately half the first order grating. This research provides technical support for expanding the range of the optical fiber sensing system and the waveband of the silicon-based detector.