Packaging of Dual-Mode Wireless Communication Module Using RF/Optoelectronic Devices With Shared Functional Components

Abstract

This paper reports the design, fabrication, and testing of a compact radio-frequency (RF)/ free space optical (FSO) dual mode wireless communication system. A modified split dual-director quasi-Yagi antenna is integrated with optical transmitter and receiver by sharing layout structural components. Bare die vertical-cavity surface-emitting laser (VCSEL) and P-i-N photodiode (PIN) are placed on antenna director pads and wire bonded to printed circuit board (PCB)-mounted laser driver and transimpedance amplifier (TIA) circuits. Detailed analysis of coupling between RF channel and associated electrical connections for the FSO channel is presented using commercial simulation tools to predict its impact on link degradation. Although crosstalk appears between RF and optical channels, the prototyped system demonstrated dual-mode high-rate communication capability with measured 2.5 Gb/s data rate in FSO link. Variations in RF subsystem features due to coupling from the FSO subsystem is estimated through radiation pattern measurement using near-field scanner.