1PhD student in Electrical and Computer Engineering, Shiraz University
2Department of Communications and Electronics, School of Electrical and Computer Engineering, Shiraz University, Shiraz
In this paper, we have presented a theoretical model to investigate the modulation response, the relative intensity noise and the frequency noise characteristics of 1.55µm tunneling injection quantum dot (TI-QD) lasers. Using a small signal model based on the carriers and photon rate equations, the modulation and noise behaviour of these lasers are simulated. Our simulations imply that the modulation response of QD laser enhances in tunneling heterostructures, which is in agreement with the reported experimental results. In fact, it is demonstrated that due to tunneling of carriers directly to the ground state across a barrier, the modulation response enhances and the 3dB bandwidth of laser increases. Furthermore, the calculations indicate that the relative intensity noise level of this type of lasers increases due to decrease in the carrier population at the excited and wetting layer states. Meanwhile, the frequency noise level and linewidth show similar values to those in conventional QD lasers.