提出了一种利用声光调谐方法进行滤波的扫频光源来提高它的输出稳定性。阐述了实现光源稳定输出的原理和方法, 研究和分析了光源的相关参数。该系统采用声光调谐的方法代替机械滤波的方式。在一个环形腔内, 使用半导体光放大器(SOA)作为增益介质, 声光可调谐滤波器(AOTF)作为波长选择元件, 利用声光调谐的原理对腔内的光进行选频滤波。在280 mA的注入电流下, 得到了1 294~1 368 nm的扫频光源, 其中心波长为1 328 nm, 半高全宽为51 nm, 扫频速度为3 731 Hz, 环形腔内直接输出的光功率为1.14 mW。由于AOTF是电控制元件, 波长的调谐不需要机械移动部件, 故提高了系统的稳定性, 输出光谱的重复性也很好。实验显示: 通过这种方法获得的扫频光源输出稳定, 基本满足扫频相干层析成像系统对扫频光源工艺参数的要求。

A swept-source laser by using an Acousto-optic Tunable Filter(AOTF) was researched to improve the stability of the source output. The principles and method to implement output stability of the source were described, and corresponding parameters of the source were analyzed. An acousto-optic tuning was selected to replace the mechanical filtering to improve its output stability. A Semiconductor Optical Amplifier(SOA) was used as a gain medium and the AOTF was used as a wavelength-selected element in an internal fiber ring cavity. The acousto-optic interaction was used in the filtering of light in the cavity. With the SOA injection current of 280 mA, the continuous wavelength tuning range of the source is from 1 294 to 1 368 nm centered at a wavelength of 1 330 nm, and its sweep rate is 3 731 Hz, the full width at half maximum is 51 nm and the output power from the ring cavity is 1.14 mW. By using the electric control element AOTF, the system implements the electronic tuning without mechanical movement elements, so it shows good output stability and excellent spectral repetition. It concludes that the swept-source laser obtained by this method has a stable output and satisfies the requirements of the other parameters of the swept source optical coherence tomography.