An all-fiber optical laser pulse multi-pass stretcher using a chirped fiber Bragg grating (CFBG) is demon- strated. Pulses from a 1 053-nm mode-locked fiber seed oscillator are stretched by multiple passing through a chirped fiber grating set in a fiber regenerative amplifier structure. We stretch the pulse from 16 ps to 1.855 ns after it transmits seven loops in the stretcher. The main factors that affect the stretching results are discussed.

An all-fiber optical laser pulse multi-pass stretcher using a chirped fiber Bragg grating (CFBG) is demon- strated. Pulses from a 1 053-nm mode-locked fiber seed oscillator are stretched by multiple passing through a chirped fiber grating set in a fiber regenerative amplifier structure. We stretch the pulse from 16 ps to 1.855 ns after it transmits seven loops in the stretcher. The main factors that affect the stretching results are discussed.

A high-speed 8-channel fiber Bragg grating (FBG) sensing system is designed to monitor safety of modern ships and applied to measure strain distribution of large thruster structure with 335-Hz maximum natural frequency. All the monitoring points are tested synchronously, and the data acquisition frequency is 1 000 Hz. The strain resolution of the system is 1 με with the measurement range of ±3 300 με. Results from the tests onshore and at sea are discussed together to accomplish prediction of the dynamic data. The max stress of the whole structure is more than 40 MPa. Experimental results are accordant with mechanical theories.

A high-precision temperature-controlled narrow band-stop fiber Bragg grating (FBG) filter and light source self-calibration technique are proposed for application in the Brillouin optical time domain reflectometer (BOTDR) sensor system. With the proposed application, the BOTDR sensor system maintains good long-term stability and temperature precision through the reduction of the center wavelength drift in the FBG filters and corresponding decrease in the changes in light intensity. The experiment result shows that temperature precision of 1°C and temperature stability of 0.7°C can be achieved in a temperature sensor over a range of 8 km.

A dual-source distributed optical fiber sensor system with combined Raman and Brillouin scatterings is designed for simultaneous temperature and strain measurements. The optimal Raman and Brillouin signals can be separately obtained by adjusting the powers of the two sources using an optical switch. The temperature and strain can be determined by processing the optimal Raman and Brillouin signals. The experimental result shows that 1.7 ℃ temperature resolution and 60-με" strain resolution can be achieved at a 24.7-km distance.

A high-speed 8-channel fiber Bragg grating (FBG) sensing system is designed to monitor safety of modern ships and applied to measure strain distribution of large thruster structure with 335-Hz maximum natural frequency. All the monitoring points are tested synchronously, and the data acquisition frequency is 1 000 Hz. The strain resolution of the system is 1 με with the measurement range of ±3 300 με. Results from the tests onshore and at sea are discussed together to accomplish prediction of the dynamic data. The max stress of the whole structure is more than 40 MPa. Experimental results are accordant with mechanical theories.

提出了一种基于分布式布里渊光纤传感系统的温度快速测量方案。该方案基于外差相干检测原理，利用高速脉冲检波管对布里渊散射信号进行直接探测，从而缩短了测量时间；并结合累加平均与小波变换技术，减小了布里渊散射信号中的噪声，通过对去噪后的信号进行解调实现了长距离温度测量。实验结果表明，在24.8 km的长度范围内，温度测量误差小于3 ℃，测量时间小于3 s。

A high-precision temperature-controlled narrow band-stop fiber Bragg grating (FBG) filter and light source self-calibration technique are proposed for application in the Brillouin optical time domain reflectometer (BOTDR) sensor system. With the proposed application, the BOTDR sensor system maintains good long-term stability and temperature precision through the reduction of the center wavelength drift in the FBG filters and corresponding decrease in the changes in light intensity. The experiment result shows that temperature precision of 1°C and temperature stability of 0.7°C can be achieved in a temperature sensor over a range of 8 km.

A dual-source distributed optical fiber sensor system with combined Raman and Brillouin scatterings is designed for simultaneous temperature and strain measurements. The optimal Raman and Brillouin signals can be separately obtained by adjusting the powers of the two sources using an optical switch. The temperature and strain can be determined by processing the optimal Raman and Brillouin signals. The experimental result shows that 1.7 ℃ temperature resolution and 60-με" strain resolution can be achieved at a 24.7-km distance.