• Patent

High injection bipolar transistor


Enquist, P. (1998). IPC No. U.S.High injection bipolar transistor (Patent No. 5780880.)


An optoelectronic semiconductor device using stimulated emission and absorption to achieve the functions of detection, modulation, generation and/or amplification of light. In one embodiment, the device includes a waveguide heterojunction bipolar transistor (HBT) biased in the active mode where the minority carrier concentration in the base is designed with bandgap engineering to optimize optical gain in this region. This HBT configuration allows optical modulation at considerably higher frequencies and/or with improved efficiency compared to the prior art, and is particularly suited to the fabrication of direct or external modulated wideband fiber optic links.