提出一种基于线性变化电流注入以改善分布反馈半导体光放大器的滤波及双稳特性的实现方案,并借助耦合模方程及载流子速率方程,将该方案与相移、啁啾非均匀分布反馈半导体光放大器的特性作了分析比较。结果表明,该方法既有与相移效应相似的透射谱,又有与啁啾效应相似的频带较宽、双稳环上支较平坦的特点,且有效提高了开关对比度。

The distributed-feedback semiconductor optical amplifiers (DFB-SOAs) possess the dual functions of amplifier and filter due to the built-in grating. If the input power is close to saturation value, dispersive optical bistability occurs as a consequence of the positive feedback loop informed among the optical intensity in active-layer, effective mode refractive index, and resonance amplification frequency. By introducing spatial phase-shift and chirp, the filter and bistable performances can be improved. A novel configuration based on linearly variable current injection is proposed to improve the filter and bistable characteristics of the DFB-SOAs. The coupled mode equation and carrier rate equation are used to perform characteristic comparisons of this configuration with phase-shifted and chirped DFB-SOAs. The results show that, this method not only enhances the on-off switching ratio, but also has similar transmission spectra with phase-shift effect method, and similar bistable features, such as the wide-band and the flat upper branch of the hysteresis, with chirp effect method.