System and method for detecting self-coherent characteristic of laser device

The invention discloses a system for detecting the self-coherent characteristic of a laser device. The system comprises a first coupler, a reflecting mirror, a first adjustable fiber delayer, a second adjustable fiber delayer, a second coupler, a receiver and a signal analyzing and detecting device. By adjusting delaying of the first adjustable fiber delayer and the second fiber delayer, the signal analyzing and detecting device receives interference electrical signals output by the receiver, and analyzes the electrical signals to obtain the maximum self-coherent length of the laser device according to the coherent effect of the coherent electrical signals. The invention correspondingly discloses a method for detecting the self-coherent characteristic of the laser device. By implementing the system and method for detecting the self-coherent characteristic of the laser device, the self-coherent characteristic of the laser device can be detected conveniently, and the accuracy and precision are high.