Heterojunction bipolar light-emitting transistors (HBLETs) fabricated with a lateral emission geometry for real-time optical wireless transmission.

Heterojunction bipolar light-emitting transistors (HBLETs) with a cleaved facet in the lateral direction for light emission are proposed for real-time optical wireless transmission. To prevent light shielding by the top metal electrodes, the light output power of the edge-emitting HBLETs exceeds that of those emitting from the top surface. Although the proposed HBLETs can generate spontaneous light emissions at λ ~965 nm, a reduced common-emitter current gain (β ~ 0.41) was found due to some of the minority carriers (electron) from the emitter being radiatively recombined within the In 0.15 Ga 0.85 As/GaAs multiple-quantum-well containing base layer. Results also show that a 300 Mbit/s optical link can be constructed using the proposed HBLET transmitter with a lateral emission geometry but its modulation bandwidth is as high as 237.5 MHz. The paper also describes the use of HBLET-based optical wireless communications to achieve real-time transmissions of digital TV signals over a distance of 100 cm in free space. • HBLETs are used as optical transmitter for optical wireless communications.. • The lateral emission geometry of HBLETs is useful to increase the light output power.. • Proposed HBLETs not only exhibit a high modulation bandwidth of 237.5 MHz but also enable 300 Mbit/s optical transmission.. • Real-time transmission of digital TV signals over a 1 m optical link is shown to be feasible using proposed HBLETs. [ABSTRACT FROM AUTHOR]