Fabry-Pérot optical filter assembly: a candidate for the Mie/ Rayleigh separator in EarthCARE.

This paper describes the development, characterisation and environmental testing of a high performance state-of-the-art optical filter for separating the Mie and Rayleigh backscatter signals for the ATLID LIDAR of the EarthCARE mission. The filter assembly utilises capacitance stabilised Fabry-Pérot étalon technology to provide high resolution optical filtering of the LIDAR signal, efficiently separating the two critical backscatter components from the atmosphere. The paper describes the development of the filter assembly and its subsequent performance testing. The filter has demonstrated state-of-the-art optical performance. Additionally, one of the étalons has been taken through complete environmental testing for space applications.