Microwave reference signal distribution on optical fibre within satellite payload

Abstract

This paper will discuss mission requirements and possible architectures of optical fibre network for the distribution of Master Local Oscillator (MLO) signals to multiple RF input ports on-board Satellite payloads. With that purpose, each of the MLO signals is modulated onto a different CW optical carrier in order to be distributed and power is equally split into multiple fibre paths while in the optical domain. The MLO signals to be delivered can be either lower power digital signals as well as high power analogue signals (> 0 dBm), and/or a combination of both, in the frequency range between 1 GHz and 20 GHz. The novel contribution of this paper is the comparison of two architectures whose main distinction is a different number of amplifiers against the required RF ports. This in turn defines the optimum way for optical amplification implementation in the optical signal distribution network. The trade-off shows that for the high number of MLOs and smaller number (<32) of RF output ports the wavelength division multiplexing (WDM) before optical amplification is preferred, while for the low MLO number and high number (>100) of RF ports distribution network the high power highly efficient optical power amplification is more beneficial. These two types of networks are compared focusing on the DC power consumption of all the equipment and the flexibility to accommodate them onto the Spacecraft.