气密封装对光纤陀螺零偏误差和长期可靠性的影响

Influence of Hermetic Packaging on the Bias Error and Long-term Reliability of IFOG

当前的应用领域对干涉型光纤陀螺(Interferometric Fiber Optic Gyroscope,IFOG,简称光纤陀螺)提出了较高的要求,如运载、航天领域要求光纤陀螺在变气压环境下精度不恶化,服役期限和存储环境要求光纤陀螺在高湿环境下可靠性高及性能稳定。而光纤对应力、水汽敏感,开放式光路结构的光纤陀螺在上述环境中性能不满足要求。通过分析气压变化对光纤陀螺零偏误差的影响以及水汽介质对光纤陀螺使用寿命、长期精度的影响,提出了对光纤陀螺光路进行气密性封装的方法。对两只气密性封装的光纤陀螺进行测试,气密性封装结构漏气率优于4×10^(-10)Pa·m^(3)/s,内部水汽含量低于5×10^(-6);两只光纤陀螺气密性封装后,在-40℃~60℃的温度范围内,零偏峰峰值降低了32.5%和31.0%,零偏稳定性误差降低了26.9%和22.2%;在变气压环境下,零偏峰峰值降低了95.3%和96.3%,零偏稳定性误差降低了96.2%和95.4%。测试结果表明,气密性封装能够显著提高光纤陀螺的精度和长期可靠性。

The application fields have put forward higher requirements for interferometric fiber optic gyroscope(IFOG).For example,when the IFOGs are placed on the launch vehicles or space vehicles,their precision should not deteriorate as the atmospheric pressure change.When the IFOGs work in high humidity environments,they should have high reliability and stable performance.As the fiber is sensitive to stress and water vapor,the performance of IFOG with open structure will not meet the application requirements.In this paper,the influence of atmospheric pressure change on the bias error and the effect of water vapor on the service life and long-term precision are analyzed,a hermetic packaging for the IFOG optical path is proposed.Two IFOGs in hermetic packaging are tested,the leakage rate is better than 4×10^(-10)Pa·m^(3)/s,the content of water vapor is less than 5×10^(-6).When test is taken in the temperature of-40℃to 60℃,the peaks-to-peaks of the bias is reduced by 32.5%and 31.0%,the error of the bias stability is reduced by 26.9%and 22.2%.When test is taken in atmospheric pressure change environment,the peaks-to-peaks of the bias is reduced by 95.3%and 96.3%,the error of the bias stability is reduced by 96.2%and 95.4%.The test results show that hermetic packaging could significantly improve the precision and long-term reliability of IFOG.