PRACTICAL LASER-BASED DISTRIBUTED FIBER BRAGG GRATING SENSOR SYSTEM |
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| Yanjun Zhang, Yuling Su, Bo Wei, Weihong Bi |
- Abstract:
- This paper presents a new type of distributed Fiber Bragg grating (FBG) sensing system based on a tunable pulse laser. The system has 500 gratings with same centre wavelengths of 1550 nm and the spacing of every grating is 3m. All gratings have been packaged and 27m delay lines are inserted between every two adjacent gratings. The scanning periodic time of tunable pulsed laser is 0.25 s; the scanning range is 1545 ~ 1555 nm; the laser pulse line width is 0.18 nm. If the grating temperature was constant, only the 1550 nm light was reflected back. But with temperature change, the grating central wavelength changed and the corresponding light pulse was reflected back. The light signals are converted to voltage pulses by the photoelectric detector and sampled by high-speed acquisition card at the 500 Msps sampling rate. The data processing system send out the voltage signals to control laser and compares these voltage signals with those sampled signals. Program will calculate the offset which linear corresponding to the gratings temperature change. In addition, reflected optical signals of different positions need different time, and the time interval of adjacent grating is 200 ns. By detecting and calculating the interval time of reflected light, the location and the temperature of the grating whose temperature has changed will obtain. Experimental results showed that grating temperature sensitivity rose at 11.4 pm/℃. The deviation between the measured temperature and the actual temperature is within 5% range. This system not only can monitor the temperature, but also can determine the location. It can meet monitoring hundreds or even thousands of different locations simultaneously. Therefore it has broad application prospects.
- Keywords:
- Fiber Bragg grating, tunable pulse laser, data processing system
- Download:
- IMEKO-TC2-2010-31.doc
- DOI:
- -
- Event details
- IMEKO TC:
- TC2
- Event name:
- TC2 Symposium 2010
- Title:
- 19th Symposium on Photonic Measurements
- Place:
- Hangzhou, CHINA
- Time:
- 11 September 2010 - 13 September 2010