Optical Frequency Division for Low Noise RF to W Band Signal Generation

Mingwen Zhu, Shangsu Ding, Zhixue Li +3 more

In long-distance fiber optic transmission, the optic fiber link and erbium-doped fiber amplifiers can introduce excessive noise, which reduces the optical signal-to-noise ratio (OSNR). The narrow-band optical filters can be used to eliminate noise and thereby improve OSNR. However, there is a relative frequency drift between the signal and the narrow-band filter, which leads to filtered signal instability. This paper proposes an adaptive OSNR recovery scheme based on a Fabry-Perot (F-P) cavity with mode width of 6 MHz. Utilizing the comb filtering of F-P cavity, the noise around the carrier and sidebands of the signal is filtered out simultaneously. To avoid frequency mismatch, we propose a double-servo scheme to suppress relative frequency drift between the signal and the F-P cavity. We constructed a stable radio frequency transfer system based on passive phase compensation and compared our scheme with other OSNR recovery schemes based on optical filters. Compared to the schemes based on dense wavelength division multiplexing (DWDM) and Waveshaper, our scheme demonstrates an improvement in OSNR of carrier by at least 12 dB and sidebands by at least 23.5 dB. The short-term transfer stability (1 s) is improved by one order of magnitude compared to DWDM and half an order of magnitude compared to Waveshper. This scheme can be applied to the recovery of signals with low OSNR in long-distance fiber optic transmission, improving signal quaility and extending the transmission distance limit.

Benjamin Pointard, Paul-Éric Pottie, M. Lours +2 more

Dieter Meschede, Harald R. Telle, Theodor W. Hänsch

Li-Hua Zhang, Bang Liu, Zong-Kai Liu +8 more

Detecting microwave signals over a wide frequency range has numerous advantages as it enables simultaneous transmission of a large amount of information, and access to more spectrum resources. This capability is crucial for applications such as microwave communication, remote sensing, and radar. However, conventional microwave receiving systems are limited by amplifiers and band-pass filters that can only operate efficiently in a specific frequency range. Typically, these systems can only process signals within a three-fold frequency range, which limits the data transfer bandwidth of the microwave communication systems. Developing novel atom-integrated microwave sensors, for example, radio frequency (RF)-chip coupled Rydberg atomic receiver, provides opportunities for a large working bandwidth of microwave sensing at the atomic level. Here, an ultra-wide dual-band RF sensing scheme is demonstrated by space-division multiplexing two RF-chip-integrated atomic receiver modules. The system can simultaneously receive dual-band microwave signals that span a frequency range exceeding 6 octaves (300 MHz and 24 GHz). This work paves the way for multi-band microwave reception applications within an ultra-wide range by RF-chip-integrated Rydberg atomic sensor.

HUANG Hai-bi, 广东工业大学 信息工程学院 广东省信息光子技术重点实验室，广东 广州 510006, Wenjie Liu +5 more

Chen Hu, Bin Luo, Wei Pan +2 more

The stable radio frequency (RF) transmission scheme involving single wavelength has received increasing attention due to the feature of accurate phase information extraction. However in single laser system, the single side band (SSB) phase noise of output signal will be deteriorated by Rayleigh scattering during long-distance optical transmission. In this work, we propose an incoherent Rayleigh scattering noise depression method in the passive phase compensation stable RF transmission scheme with single laser. The carrier of scattering light is suppressed with narrow-band optical filter based on the Stimulated Brillouin scattering (SBS) effect, so that the noise generated by the beat of scattering itself will be significantly reduced. As a result, a 5-GHz RF signal stability transmission over 50-km single mode fiber is demonstrated experimentally. The SSB phase noise at 10 KHz offset is 10.9 dB lower than the scenarios without incoherent Rayleigh scattering noise depression. Meanwhile, the phase jitter mean square error is 1.12 ps during$1\times 10^{4}$seconds.