Integration of microlensed LED and double heterojunction bipolar transistors for transmitter OEIC

Abstract

An optoelectronic integrated circuit (OEIC) consisting of a highly focusing AlGaAs microlensed LED and a double heterojunction bipolar transistor (DHBT) has been fabricated. A 30 mu m radius microlens was used to focus IR radiation into a beam-spot smaller than 3 mu m. A microlensed LED focused its output light within a full width at half maximum (FWHM) of 17 degrees in the far field pattern. An integrated microlensed LED radiated similar to 35mW of maximum light output with a driving current of 120mA, and its driving DHBT with a 10 X 15 mu m(2) emitter showed a DC current gain of beta = 20.