One-dimensional numerical analysis of transistor lasers

We demonstrate one-dimensional numerical analysis of transistor lasers (TLs). The high frequency performances of TLs and laser diodes (LDs) are compared. The charging time definitions of the TL and LD are given. The TL has a larger bandwidth and a shorter rise time than the LD due to the shorter charging time in the former. We find that the bandwidth decreases and the eye diagram of 40 Gb/s is degraded with increasing base region width of the TL. Finally, compared with the TL, the bandwidth reduction of LDs at high injection currents is due to a narrower small-signal response for the virtual states carrier density to the modulation current ratio.