Research On Integrated RF Optical Channel For Satellite Communication

High frequency broadband networks and multi-functional integration are inevitable trends in the development of satellite communication, while bringing great challenges to radio frequency channel technology. At present, electronic devices used in satellite communication have high loss, low dynamic range,volume bloated and many other shortcomings. Also, the ability to handle high frequency, wideband signals is obviously insufficien. Therefore, building high-performance, universal integrated RF channel to meet the existing challenges,is of great significance for the development of satellite communications. In this paper, combined with the broadband and flexible characteristics of microwave photonic technology, a wide-band integrated RF optical channel architecture is proposed to support multiple channels, multiple frequency bands and various signal forms. It is further investigated that sharing resources of local oscillators and channels, dynamic and flexible routing, and the main work and achievements are as follows:Aiming at the redundant configuration of the local oscillator and other resources of the satellite system, the scheme of the microwave photon local oscillator based on Cyclic AWG cyclic shift characteristic is studied. The simulation of the distribution theory is verified by the optical system simulation software VPI. Based on the unified scheduling and allocation of photonic local oscillator, this paper studies the sharing schemes of local oscillators and channels for multi-beam multi-band signals. Experiments show that the two signals shared by the local oscillators or the channels have more than 70dB of isolation in the optical domain, and the corresponding intermediate frequency signal has good clutter suppression ability, and the dynamic range can reach 100 dB·Hz2/3 or more. Using the QPSK modulation format signal, the signal impairments after down-conversion of the RF optical channel are tested,deteriorating less than 8% compared to the direct transmission EVM. With input signals up to 40 GHz, the RF channel has a flat dynamic range with a variation of no more than 5%.This paper studies the dynamic routing switching scheme based on the wavelength selective switch and supports broadcast and multicast, and implements the function of the hardware and software for routing and switching unit in the RF optical channel. The experimental results show that the switching time of any route is between 0.05s and 0.12s, the isolation between different output ports is close to 70 dB, and the dynamic range of the system is as high as 104 dB·Hz2/3, which satisfies the design requirements of on-board RF channels.