The Optical Interference Cancellation System: Design of a Photonic Integrated Circuit for RF Interference Cancellation

Abstract

In the advent of rapidly growing wireless technology and shrinking available RF spectrum, self-interference is becoming an increasingly urgent problem. The optical interference cancellation system (OCS) serves as a solution to this problem since it can make a replica of the interference in a transmission channel and subtract the replicated interference from the received signal, which is the signal of interested coupled with the interference signal, thus cancelling interference. We want to further improve the cancellation results of the on-chip OCS through PICWave simulation, which would allow us to efficiently study how circuit performance varies with different parameters. The goal of our project is to design the photonic integrated circuit (PIC) for maximum broadband interference cancellation in the OCS through finding the optimal operation parameters for all on-chip OCS components.We began our simulations by characterizing individual OCS components, which include the DFB laser, semiconductor amplifier, photodetector. We also constructed the frequency response plots of these components to measure their bandwidth, allowing us to pinpoint which components will limit the bandwidth performance of the OCS. We then tested links of components, including the DFB laser and balanced PD link, as well as the DFB laser, SOA, and balanced PD link. Frequency response plots are also measured to allow us to compute bandwidth performance, link loss, and evaluate the consistency of the behavior of linked components with the behavior of individual components. Finally, we simulate the complete OCS PIC circuit. We were able to obtain maximum cancellation at 46.5 dB. We also achieved 45 dB cancellation over a 63MHz bandwidth. This cancellation performance is superior to the cancellation performance of both the discrete and on-chip OCS's we have previously built.