Oscillator phase noise reduction using optical feedback with dual drive Mach-Zehnder modulator

Abstract

A reduced phase noise of stable microwave oscillators is reported by forced oscillation using self-ILPLL technique fiber optical delayed feedback. Fiber optic links using single drive and dual drive MZM have been used to implement the optical feedback path. A phase noise reduction of 22 dB at 300 Hz offset is measured for a commercially available DRO at 10 GHz using dual drive MZM in long fiber optic delay lines. The measured -127 dBc/Hz at 14 kHz offset has been demonstrated by employing 4km and 8km fiber optic delay lines.