Analytical Investigation of Frequency Behavior in Tunnel Injection Quantum Dot VCSEL

The frequency behavior of the tunnel injection quantum dot vertical cavitysurface emitting laser (TIQD-VCSEL) is investigated by using an analyticalnumericalmethod on the modulation transfer function. The function is based on therate equations and is decomposed into components related to different energy levelsinside the quantum dot and injection well. In this way, the effect of the tunnelingprocess on the improvement of the laser frequency response is determined. Generally,the components of the modulation transfer function in the wetting layer and the excitedstate limit the total laser bandwidth. Of course, the component associated with thetunneling process increases overall system bandwidth. It is shown that for currentsabove threshold, the carrier density at the excited state in TIQD has a slight slope,unlike the conventional quantum dot (CQD). It will improve the frequency response ofthe tunnel injection structure. It can be attributed to the difference in Pauli blockingfactor values at the excited state and the ground state in the two structures.