Stable and Frequency-Hopping-Free Microwave Generation Based on a Mutually Injection-Locked Optoelectronic Oscillator and a Dual-Wavelength Single-Longitudinal-Mode Fiber Laser

Abstract

We report a novel method to generate a stable and frequency-hopping-free microwave signal based on a mutually injection-locked dual-wavelength single-longitudinal-mode fiber laser and an optoelectronic oscillator (OEO), with the mutual injection locking realized by sharing an optical path consisting of a polarization modulator and a polarization-maintaining phaseshifted fiber Bragg grating. The two wavelengths from the fiber laser are injected into the OEO to lock the generated microwave signal, while the microwave signal from the OEO is fed back into the fiber laser to injection lock the two wavelengths. Thanks to the mutual injection locking, the operation stability of the fiber laser and the OEO are substantially improved. A microwave signal at 11.8 GHz with a phase noise of −105 dBc/Hz at a 10-kHz offset frequency is generated. A stable operation of the system without frequency shifting and hopping is demonstrated.Index Terms-Erbium doped fiber amplifier, fiber Bragg gratings, fiber laser, injection locking, microwave, optoelectronic oscillator (OEO), phase shift, single longitudinal mode.