Photonic RF-IF wideband down conversion using optical injection locking

Abstract

We describe the implementation of a self-heterodyne, tunable down converting RF-IF photonic link as a key component of a wideband microwave signal search and intercept system covering S to Ka bands. The presented architecture uses photomixing of two distributed feedback lasers injection locked to a master external cavity laser, allowing low phase to amplitude noise conversion and improved sensitivity. Coherent detection of the intermediate frequency allows unambiguous recovery of full time-domain information. The practical implementation of a packaged prototype system will be discussed, with emphasis on the system stabilization strategy and performance requirements.