中文摘要：

针对连续波腔衰荡技术的激光关断问题，本文提出通过调制激光器的驱动电流，即激光去谐方法，使连续波激光与衰荡腔离开谐振状态，实现对入射光的快速关断。该方法根据电流调制特点实现以往系统中声光或电光开关的功能，不需用外部光开关来切断光源，系统更加简便，节省成本。设计了基于激光去谐的连续波腔衰荡技术系统，分析了各器件的性能和工作原理，分析了去谐过程的特性，比较了激光去谐与激光关断的区别。结果表明，调制电流的关断时间比传统的光开关更短，衰荡曲线的单指数线形更加明显。

英文摘要：

To ensure turning-off the laser in the system of continuous wave cavity ring-down technology, a new method for modulating laser current, named as laser detuning is proposed. With this method, the resonant state between the laser and ring-down cavity is ended. Hence, the incident laser to the ring-down cavity can be turned off rapidly. This detuning method does not require external optical switches （such as the acousto-optic modulator） to turn off the laser source so the system is simpler than previous ones and the cost is lower than traditional systems. The continuous wave cavity ring-down system based on the laser detuning is designed. The operating principle and performance of various devices are analyzed. The characteristics of the detuning process are analyzed and the difference between the laser detuning and laser tum-off are compared. As a result, the turning-off time in the technology of modulating laser current is shorter than the traditional optical switches, and the exponential curve is more distinct.