This paper presents the technical solutions implemented with the support of the French Space Agency (CNES) to design and manufacture hermetic Lithium Niobate (LiNbO<sub>3</sub>: LN) modulators, in the framework of a Research & Technology (R&T) project . There is also presented some identified space-compatible raw materials that constitute modulators and some relevant results of a space evaluation program realized on about fifteen of these hermetic modulators (including hermeticity tests, mechanical tests and climatic tests).
Light propagation in small-core photonic crystal fibers enables tight optical confinement over long propagation lengths to enhance light-matter interactions. Not only can photonic crystal fibers compress light spatially, they also provide a tunable means to control light-hypersound interactions. By exploring Brillouin light scattering in a small-core and high air-filling fraction microstructured fiber, we report the observation of Brillouin scattering from surface acoustic waves at lower frequencies than standard Brillouin scattering from bulk acoustic waves. This effect could find potential applications for optical sensing technologies that exploit surface acoustic waves.