微腔效应可以提高自发辐射速率, 从而起到有效的改善响应调制速率的作用.然而, 对于1.3 μm GaAs/InAs量子点光子晶体激光器而言, 调制速率还会受到复杂的载流子动力学以及更近的空穴能级间隔的影响.因此基于全路径载流子弛豫动力学方程, 计算并讨论了腔品质因子(Q)对于阈值和响应调制特性的影响.计算结果表明, 高的Q值能够明显改善量子点光子晶体激光器的阈值, 但是同时快速增长的光子寿命会导致调制带宽的恶化.所以, 存在一个优化的Q值(2500)可以获得超过100 GHz的调制带宽, 而当Q值为7 000时, 对应的能量传输损耗最低.因此, 在量子点光子晶体纳腔激光器的设计中, 更全面的考虑各方面的因素对器件的性能的影响, 对于获得高速调制低功耗的量子点激光器器件是十分有意义的.

It had been proposed that the microcavity effect could enhance the spontaneous emission rate and hence dramatically increase the modulation speed. However, the work in this paper reveals that the situation might not be completely correct for the 1.3 μm GaAs based quantum dot (QD) photonics crystal (PhC) nanolasers due to the complex carrier dynamics and close hole levels. Based on the all-pathway rate equation model considering the carrier relaxation dynamics, the influences of quality (Q) factor of cavity on the threshold and modulation responses of 1.3 μm QD PhC nanolasers were studied. It is found that the high Q factor can improve significantly the threshold of QD PhC nanolasers, but it also increases the photon lifetime and deteriorates the modulation bandwidth. Hence there exists an optimized Q factor (~2500) for the nanolaser with a modulation bandwidth exceeding 100 GHz. For the energy consumption, the best value corresponds to a Q factor of ~7 000. So an overall consideration is preferable in designing PhC nanocavity for both high speed and low energy consumption operation of QD lasers.