Diffraction intensity distribution of varied line-space blazed grating for broadband source

The varied line-space grating displacement sensor is a novel wavelength encoding displacement sensor, it is one of the vital components of developing fly by light (FBL) control technology. A varied line-space grating with high diffraction efficiency is necessary to enhance measurement precision and decrease the cubage of lamp-house. First, the calculation formula of diffraction intensity of the varied line-space blazed grating was deduced based on classical optical. It was theoretically improved that the varied line-space blazed grating could increase diffraction intensity of the sensor. In addition, the prototypes of the varied line-space blazed grating were fabricated and the feasibility of process was verified. Comparative experimental researching on diffraction intensity of varied line-space blazed grating and varied line-space rectangular grating was made at the same conditions. The experimental results show that the diffraction intensity of varied line-space blazed grating is 1.7 times than varied line-space rectangular grating which is consistent with the result of calculation formula of diffraction intensity.