Experimental Investigation on the Side Mode Injection Locking of a Single-loop OEO under RF Signal Injection

This article mainly focuses on the side mode injection locking phenomena when a single-loop optoelectronic oscillator (OEO) is under RF signal injection. The analyses are made regarding lock range, phase noise and locking time. Also, a comparative study has been prepared when the OEO is injection-locked in the first side and the main mode. We show that the lock range is smaller for injection-locked OEO in the first side mode than in the main mode. The phase noise performance of the OEO for both cases is also demonstrated. It is exhibited that the phase noise performance is better in the case of injection-locked OEO at first side mode, particularly in a strong injection regime. The transient behaviour is also approximated by measuring locking time in both cases. The lock range, phase noise and locking time dependency on optical fibre length have also been studied. Finally, we perform experiments to support our analytical findings developed earlier.