Abstract
In this paper, the dynamic response of the optical gain of optical integrated device composed of a heterojunction bipolar transistor (HBT) and a laser diode (LD) has been numerically analyzed. This type of optical integrated device is called transistor laser (TL). First, the rate equation of LD has been solved to obtain its transfer function. Second, the overall transfer function of the whole structure has been analyzed numerically. The effect of HBT cutoff frequency on the amplitude and phase frequency response has been studied. The obtained results show that HBT has a strong influence on the device performance. In particular, higher values of HBT cutoff frequency result in lower amplitudes and higher phase values in the low-frequency range. The device is stable and has a fast response and high optical gain at higher frequencies. Therefore, it can be used as an optical amplifier or optical switch in high-speed optical systems.