Noise performance of HBT as photodetector in analog fiber-optic communication link

An analog fiber-optic communication link using a heterojunction bipolar transistor (HBT) as photodetector is analyzed regarding its noise performance Experimental results for signal-to-noise ratio and distortion are compared to other state of the art devices as well as commercial ones. The shot noise limited system using the HBT demonstrated S/N in excess of 50 dB and spurious-free dynamic range better than a commercial PIN. Furthermore, compared to other 3- and 2-terminal devices the HBT is potentially the best candidate for future OEIC technology. Experimental results for a new HBT structure, optimized for photonic applications, shows significant improvement in terms of gain and sensitivity.