AbstractActive clearance control has been used to improve efficiency and performance in commercial aircraft engines. This paper describes a optical fiber sensor for active control, which is simple and thin in structure. The sensor system data sampling rate is about 100kHz, and its resolution ratio is better than 0.01mm. Sensor's ability to monitor tip clearance was tested using a rotor test rig and individual blade tip clearances at different speed and a blade failure measurement example was given. The results show: the sensor was able to detect the blade flaws, and have a large bandwidth, high data sampling rate. It will be presented to show the viability of the sensor for use in active clearance control.