垂直腔面发射激光器的饱和效应对慢光延时影响的研究

通过理论和实验研究了1550 nm量子阱垂直腔面发射激光器(QW-VCSEL) 的饱和效应对2.5 Gbps二进制伪随机序列(PRBS)慢光延时的影响. 利用Fabry-Perot腔边界条件结合光场分布, 推导出VCSEL中信号相位和延时表达式, 并结合速率方程, 建立信号功率与延时之间的联系. 实验研究了在VCSEL逐渐达到饱和状态过程中PRBS信号的延时时间和眼图的变化情况. 理论和实验结果表明, 由于受饱和效应的影响, 大功率信号在VCSEL中传输得到更好的信号质量, 但以牺牲延迟时间为代价. 为了获得较大的时延, 一方面需要控制信号功率, 其次还需要调节信号波长以追踪由于饱和效应导致的VCSEL峰值增益波长的变化轨迹.关键词：慢光延时垂直腔面发射激光器饱和效应

Dependence of slowing light in vertical-cavity surface-emitting laser on saturation effect

The dependence of slowing light on the saturation effect in the vertical-cavity surface-emitting laser (VCSEL) is demonstrated. Combining the boundary conditions with the optical field distribution in VCSEL, the phase expression and the delay expression of the signal are derived. Based on these expressions and the rate equation, the relation between signal power and time delay is presented. Then the experimental demonstration shows the delays and the eye diagrams of a 2.5 Gbps pseudo-random binary sequence (PRBS) signal, when the VCSEL is working in the saturation condition. The theoretical and experimental results show that the high-power signal transmitted in the VCSEL could achieve better signal quality at the expense of the lower time delay. In order to obtain larger delay, on the one hand, the signal power should be controlled. On the other hand, the signal wavelength should be carefully adjusted to track the peak gain wavelength of the VCSEL caused by the saturation effect.