An optimized spectral response the HBT inp/ingaas as an optoelectronic mixer mm-wave radio over fiber

Abstract

The optoelectronic mixing is an attractive approach for high frequency in millimeter wave band due to an advantages of low loss and modulate high frequency signal for up and down conversion. Due to this advantage, it is practical implementation of RoF whereby it performs the detection and frequency conversion simultaneously that are required at antenna BS. Heterojunction Bipolar Transistor (HBT) enable to photodetects and optoelectronic converters for radio over fiber communication systems [1, 2]. Hence, HBT has been identified as a suitable candidate of an OEM by simultaneously photodetecting an intensity modulated wavelength frequency translating the detected signal to a higher or lower frequency which can provide high mixing efficiency up to 30GHz. In this work, analysis of the spectral model of HBT in lattice-matched InP/InGaAs as an optoelectronic mixer in millimeter-wave radio over fiber (RoF) has been done thoroughly. The proposed HBT was analysed by considering the wavelength of 1310nm and 1550nm for an upconversion frequency of 20GHz. It was found that the optimum device parameters and characteristics of spectral response were determined based on the influenced of optical window 5x6µm2 and 8x8µm2 and responsivity of the device. The responsivity of the HBT obtained is 0.2 A/W at 1550nm wavelength and 0.3A/W at 1300nm. The characteristics was further investigated to develop the appropriate structure device for OEM application. The proposed HBT InP/InGaAs is for heterodyne RoF transceiver system to perform photodetection and frequency up-conversion in millimeter wave RoF.