Low-Cost Multistandard Radio-Over-Fiber Downlinks Based on CMOS-Compatible Si Avalanche Photodetectors

We demonstrate a radio-over-fiber downlink based on a silicon avalanche photodetector (APD) fabricated with 0.18-$mu$m standard complementary metal–oxide–semiconductor (CMOS) technology. An 850-nm vertical-cavity surface-emitting laser is used to deliver multistandard services including 2.1-GHz wideband code-division multiple access and 2.4-GHz IEEE 802.11g wireless local area network signals over 300-m multimode fiber. These signals are successfully detected by a CMOS-compatible APD (CMOS-APD) and then transmitted to a mobile terminal via wireless link. The error vector magnitude performance of each type of signal with the coexisting interferer is investigated.