US Patent 11942750 Laser inspection system

A laser inspection system is provided. A laser source emits a laser with a first spectrum and the laser is transmitted by a first optical fiber. A gain optical fiber doped with special ions is connected to the first optical fiber, and a light detector is provided around the gain optical fiber. When the laser with the first spectrum passes through the gain optical fiber, the gain optical fiber absorbs part of the energy level of the laser with the first spectrum, so that the laser with the first spectrum is converted to generate light with a second spectrum based on the frequency conversion phenomenon. The light detector detects the intensity of the light with the second spectrum, so that the power of the laser source can be obtained.