Compared with normal reflecting scanning transform Spectrometry, cube-based Spectrometr is a key component in the time-based modulation interference spectrometer, it have more compact structure ,using less accessory , easy to fix up , more steadily and more practicality . Calculations on optical path difference (OPD) of spectrometry play an important role in analyzing and improving of the structure. Following the law of Malus and the geometrical relationship of model, get the formula of OPD and the affective factors .The calculation results demonstrate that OPD is closely related to the tilted angel of rotating reflector , the size of cube reflector and the refractive index of reflector. And this kind of spectrometry has the character of high resolution, especial in some spectrum.

Due to the complex structure of the rolling bearing, a simplified bearing model was founded and then thermal stress simulation was analyzed with ANSYS. The various parts of the displacement changes can be got. Compared the simulation results with the actual results, it can be drawn that the simulation result is basically same with the analytical result. So the simplified model is right. This method is simple, and can be adapted to the general clearance analysis.