The pipeline leak detection and leak location problem have gotten extensive attention in the industry. In this paper, the distributed optical fiber sensing system is designed based on the heat supply pipeline. The data processing method of distributed optical fiber sensing based on LabVIEW is studied emphatically. The hardware system includes laser, sensing optical fiber, wavelength division multiplexer, photoelectric detector, data acquisition card and computer etc. The software system is developed using LabVIEW. The software system adopts wavelet denoising method to deal with the temperature information, which improved the SNR. By extracting the characteristic value of the fiber temperature information, the system can realize the functions of temperature measurement, leak location and measurement signal storage and inquiry etc. Compared with traditional negative pressure wave method or acoustic signal method, the distributed optical fiber temperature measuring system can measure several temperatures in one measurement and locate the leak point accurately. It has a broad application prospect.
In optical fiber spectroscopy research, adsorbent is frequently used on gas sensing detection. But traditional solid adsorbent have some adverse effect for optical transmission. In this paper, liquid film is used as the CO adsorbent. The base tube is hollow core waveguide. Liquid is coated to the inner surface of the hollow core waveguide. And the both end of the tube are packaged to FMA905 connector. The surface of the liquid film is smooth. So it has small scattering and high detection efficiency. The sensor with 48cm length is used to CO detection. The limit detection concentration can be achieved about 20 ppmv.