Flexible New Opto-Microwave Design Approach for Radio-Over-Fiber Applications: A Case Study of Low-Cost 60-GHz VCSEL-Based IF-RoF Link

This paper introduces and defines a novel complete set of optical-microwave (OM) quantities to analyze radio-overfiber (RoF) systems. Our approach defines the equivalent optomicrowave power, gain, noise figure (NF), 1-dB compression point and third-harmonic intermodulation product (OM-P1dB, OM-IP3), spurious-free dynamic range (SFDR), and error-vector magnitude (EVM) expressed in the OM domain. These figures of merits are defined at the component level for each device of the RoF link with the practical illustration of the transmission of IEEE802.15.3c 60-GHz signals along an intermediate-frequency RoF scheme. A behavioral model is developed to implement those quantities into a microwave simulator and is exploited to turn the EVM measurements into a means of providing an original extraction method of devices properties. Such a technique is applied on the evaluation of state-of-the-art 850-nm GaAs vertical cavity surface emitting laser that demonstrates advanced performances with an output OM-P1dB of -4.17 dBm, output OM-IP3 of 2.43 dBm, OM-NF of 34.3 dB, and OM-SFDR of 101.5 dB · Hz
^2/3
. The method is applied further to extract the characteristics of various photodetectors such as a commercial photodiode with an integrated transimpedance amplifier revealing an input OM-IP1dB of -41 dBm. The technique will be crucial for the optimization of further RoF links and devices.