Stable and Compact Dual-Loop Optoelectronic Oscillator Using Self-Polarization-Stabilization Technique and Multicore Fiber

Abstract

We experimentally demonstrate a stable and compact dual-loop optoelectronic oscillator (OEO) using multicore fiber and self-polarization-stabilization technique. Two fiber cavities using two standard single mode fibers with different length in traditional dual-loop OEOs are replaced by only one multicore fiber where several cores are linked together to form the short and the long cavity simultaneously. Thanks to this fiber-integrated medium, the OEO relative stability is enhanced and the required cavity length is decreased. To avoid the influence from unstable polarization states of optical signals in these two fiber cavities, a self-polarization-stabilization technique is proposed. Therefore, no additional polarization controller and polarization maintaining fiber are required, contributing to further shorter fiber length in cavities and more compact structure. Moreover, the frequency and power stability of the generated RF signal in OEO is improved a lot compared with the traditional dual-loop OEO using the polarization division multiplexing technique. The experimental results show that the frequency and power drift of the generated RF signal with frequency of 7.8 GHz are within 0.59 ppm and 0.44 dB during 1 h, respectively. Furthermore, by introducing a tunable microwave photonics filter, a frequency tunable OEO is achieved. The experimental results show that the frequency of the generated RF signal could be tuned from 3.5 to 17.1 GHz, the phase noise performance at 10 kHz frequency offset is around −100 dBc/Hz in whole frequency range, and the side mode suppression ratio is 61 dB.