Optical harness (OHA) for future L-band radiometer

Soil Moisure and Ocean Salinity (SMOS) was the first ESA satellite relying on a complete optical harness, which was initially selected for the mechanical properties of optical fibre, what facilitated the deployment of the 3 arms of the instrument. In addition, other interesting advantages of the optical harness, as immunity to electromagnetic interference, high bandwidth, low losses and mass, etc., played an important role in the instrument performance. In the frame of the the ESA ITI contract No 4000120740/17/NL/AI, based on the advantages of optical cables and the good results obtained in SMOS mission, DAS team along with Airbus DS is studying different optical harness configurations as an evolution towards a full optical harness system for a future SMOS Operational (SMOS-OPS) Lband radiometer. In particular, different Optical Harness (OHA) configurations have been studied in order to select the two most promising options. The first configuration aims at solving some identified issues as well as at improving performance of SMOS thanks to lessons learnt from the in-orbit operation, but without attempting novel techniques of calibration or signal distribution.The second configuration explores the application of alternative techniques like the use of WDM or multi- RF over fibre. The main goals of this second configuration are the improvement of the electrical performance and the optimization of the optical harness in terms of layout, i.e, to reduce number of cables/fibres, size, weight, as well as power consumption.