An All-Optical Ka-Band Microwave Long-Distance Dissemination System Based on an Optoelectronic Oscillator

Abstract

We proposed an all-optical Ka-band microwave long-distance dissemination system based on an optoelectronic oscillator (OEO). In this system, a single tone with high spectrum purity and low phase noise is excited by an injection-locked OEO, and distributed to the remote site through the fiber loop of the OEO at the same time. The second harmonic of the reference signal modulates the round-tripping optical signal at the local site, which achieves the phase conjugator at the optical domain. At the remote end, the phase-conjugated signal is photomixed with the OEO signal to eliminated the phase offset. The proposed scheme improves the phase noise of the high frequency signal received at the remote site and reduces the photoelectric conversion loss. We demonstrated the transmissions of a 36 GHz frequencyquadrupled RF signal along a 6 km optical fiber loop, and the frequency stability is 1.069×10 -14 /1s and 3.3×10 -16 /1000s. The single-sideband (SSB) phase noise of the received signal at the remote site is up to -130 dBc/Hz at 10 kHz offset frequency.

Chromatic Dispersion Compensation in Phase-Stabilized Dissemination System of Broadband Signals Based on Phase Conjugation

“…For simplicity, we will analyze the case of only one remote antenna unit, however, the corresponding principles apply to any remote base station with the same configuration. In our previous studies, it has been shown that a similar structure can suppress phase fluctuation caused by fiber temperature drift and achieve stable transmission of a single frequency [19], [20]. In this paper, we derive in detail the process of automatic elimination of dispersion and explain the structural principles of vector signal generation without precoding modulation verification.…”