High Sensitivity Envelope Detector Assisted by Microwave Photonics

This article presents a concept of an envelope detector with a high sensitivity value based on Microwave Photonics (MWP). The process of envelope detecting of RF signals is achieved by the translation of the RF spectrum to the optical spectrum range followed by optical filtering to cut the lower sideband and the carrier. Finally beating the optical components of the remaining upper sideband into a low-speed photodetector, as a self-homodyne process. This approach depends only on the RF passing band of the phase modulator and the optical filter transfer function. This concept is experimentally demonstrated reaching envelope detector sensitivity values around 53,000 V/W for RF input frequency range of 10 GHz to 20 GHz. The proposed architecture does not use any optical or video signal amplifier. The implementation of this approach is simple, employs few components, and Commercial off-the-Shelf (COTS).