Optimized Design Of Fixing Modes Of Crystal In Differential Laser Gyros

Differential Laser Gyros are better than Dithered Ring Laser Gyros in theory, but in fact the performance of Differential Laser Gyros are always worse than Dithered Ring Laser Gyros' at present because of technical problem. In order to improve the performance of Differential Laser Gyros, the problem of fixing must be optimized. This thesis mainly includes analyse of theory and demonstration of experiments.Firstly, Jones matrix representing the performance of Crystal is analyzed in theory, and the arithmetic of computing ellipticity angle and azimuth recuring to computer is brought forward. The effect of Jones matrix on the performance of gyros is analyzed , including differential loss, eigenpolarizations and frequency of levorotatory and dextrorotatory gyros, the measure of avoiding differential loss is put forward. It is found that both eigenpolarizations and refractive index of crystal are so important that none of them can be ignored. The effect of stress on the crystal is computed in theory and their relation curves are shown, which show that lengthways stress and transverse symmetry stress have small effect on crystal; It is estimated that safety stress is 10~6 N/M~2, safety force is 1N and safety strain is 10~-5 when the performance of crystal is not affected. The effect of acceleration and changing of temperature on the crystal are analyzed , It's found that the first effect is in the range of safety force, the second effect can be ignored when it can expand freely ,otherwise it is equivalent to the outside force effect.Secondly, the problems of the current fixing mode are analyzed, and three fixing modes are brought forward. The square-symmetry fixing mode is considered optimized and feasible by considering the fixing feasible principle. It is the innovation of the thesis that the sensitivity of the crystal is decreased by improving the symmetry of the transverse stress.Lastly, the outside force experiments have been done and it is proved that the estimate of safety force is right, the square-symmetry fixing mode is optimized and feasible. At the same time, it is found that the current fixing mode is illogical because the indium is only laid on the top of the crystal. It's much optimized if the indium is laid on both sides of the crystal.