Integrated Electroabsorption Modulator/Heterojunction Phototransistor for Passive-Picocell Radio-Over-Fiber Applications

Abstract

An integrated electroabsorption modulator/heterojunction phototransistor (EAM/HPT) is proposed for passive-picocell radio-over-fiber (RoF) applications. By utilizing the concept of a lowdetuned EAM configured in the n-p-i-n structure, we show that a very efficient optical transceiver can be realized. We first explain the concept of low detuning in the EAM and the operation principle of the EAM/HPT; then, we apply these to the design of an efficient optical transceiver for a passive-picocell RoF system. By selecting a specific base thickness and considering the optical-gain dependence on the collector-current level and the bandwidth, we estimate the possible performance of the passive-picocell RoF system when the proposed EAM/HPT is used. We show that the power margins estimated for reasonable optical-gain values can be positive up to similar to 20 m when the data are in downstream to the user.