Noise modeling of an InP/InGaAs heterojunction bipolar phototransistor

Abstract

We present a theoretical analysis of the noise behavior of a heterojunction bipolar transistor (HBT) used as a three terminal (3T) photodetector. The use of a HBT in the photodetector mode can greatly simplify the fabrication of HBT-based optical receivers in the monolithic form. The present model takes into account the effect of the received light on the intrinsic parameters and various noise components of the HBT when used as a detector. The model enables one to determine the signal-to-noise ratio at the output and also the noise equivalent power of the HBT. The model has been applied for characterization of an InP/InGaAs HBT used as a 3T photodetector in the 1.55-μm wavelength region. © 2003 Society of Photo-Optical Instrumentation Engineers.