InP DHBT transimpedance amplifiers with automatic offset compensation for 100 Gbit/s optical communications

We present the design, fabrication and measurement of two transimpedance amplifiers with single-ended input and differential output for optical fibre communication systems. The integrated circuits have been fabricated in a 0.7-μm InP DHBT technology. The small-signal differential transimpedance gain and 3-dB bandwidth are respectively 1100 Ω and 50 GHz for the first circuit and 500 Ω and > 65 GHz for the second circuit. Eye diagrams were measured at 86 Gbit/s showing clear eye opening. An automatic offset compensation loop was implemented and validated.