中文摘要：

超宽带（UWB）无线通信的关键技术之一是UWB窄脉冲产生技术。为简化光子超宽带脉冲源的设计，提出采用基于光纤可饱和吸收体效应的环形腔被动锁模光纤激光器来设计光子UWB脉冲源。为了获得满足UWB室内无线通信频谱范围的脉冲，利用色散和啁啾效应展宽脉宽的原理，在激光器环形腔内使用较长的增益光纤引入大量色散效应，将光脉冲展宽以符合美国通信委员会（FCC）规定的室内UWB通信频谱范围（3．1～10．6GHz）。并根据光纤激光器谐波锁模的原理，通过控制偏振态调制输出脉冲的周期以提高脉冲重复频率。实验中，展宽的光脉冲经光电转换器转换成UWB电脉冲序列后，由宽带数字示波器进行波形观测和测量。通过调节偏振控制器，获得了可输出8种不同脉冲重复频率的光子超宽带脉冲源。

英文摘要：

Narrow pulse generation is one of the key technologies of ultra wideband （UWB） radio wave communication. To simplify the photonic generation of UWB signal, a novel method for UWB microwave signal generation using a passively mode locked fiber laser is proposed and demonstrated. Er^3＋-doped fiber as long as 3 m is used to get enough dispersion for achieving the wider pulse width, so that the frequency range of the pulse is between 3.1 and 10.6 GHz, as defined by FCC （US Federal Communications Commission）. Based on the principle of harmonic mode-locking, the polarization is adjusted to get different periods of pulse so that the repetition rate is increased. In the experiments, the UWB signal is generated by beating the modes of passively mode-locked fiber ring laser at a wideband photo detector. A wideband numerical oscillograph is used to observe the wider pulse. The UWB photonic source with 8 different repetition rate outputs is gotten by adjusting the polarization controller.