基于色散调谐宽带扫频光纤激光器及其在光纤光栅解调中的应用

Wavelength-Swept Fiber Laser Based on Dispersion Tuning and Its Application on the Demodulation of Fiber Bragg Grating

报道了一种基于色散调谐技术的宽带扫频掺铒光纤激光器。通过在主动锁模光纤激光器腔内引入较大色散,利用锯齿波电信号调制电光调制器的调制频率,可以实现激光器扫频输出。应用扫频激光器可将光纤光栅反射中心波长的变化转变为时域上信号间隔变化,适用于光纤光栅传感解调。搭建了扫频光纤激光器,利用掺铒光纤作为增益介质,研究了扫频范围的影响因素。通过优化实验参数,实验得到的扫频带宽达到43nm,接近增益带宽,扫频速度为50Hz。利用搭建的扫频激光器进行了光纤光栅传感解调,灵敏度约为0.68ms/nm,验证了解调原理。

A large swept-range wavelength-swept Er-doped fiber laser based on dispersion tuning is reported. By introducing large dispersion in the cavity of the active mode-locked laser, the output wavelength can be swept through changing modulation frequency. The laser can be applied to fiber Bragg grating （FBG） sensing. When the output light of the wavelength-swept laser is reflected by FBG, the variation of FBG central wavelength induced by strain can be converted into different time delays of signals. The output characteristics of the wavelength-swept laser are experimentally studied. The wavelength-swept range is 43 nm approximating the gain bandwidth of Er-doped fiber, while the sweep rate is 50 Hz. The principle of this demodulation technique is demonstrated and the sensitivity is about 0.68 ms/nm.