To develop beam splitters for soft X-ray laser Mach-Zehder and Michelson interferometer at 13.9 nm, Mo/Si multilayers deposited on back side and both sides of silicon nitride with thickness of 100 nm were fabricated using DC magnetron sputtering. We presented the results of their reflectivity, transmission and probing the electron density of laser-produced plasma using a soft X-ray laser Mach-Zehder interferometer. The design and fabrication of broadband polarizers were also presented in this paper. These polarizers can be used as analyzers for a wideband polarization measurement. We discuss the results obtained with depth-graded Mo/Si multilayer analyzers for 13-19nm polarization measurements. We also discussed the development of X-ray supermirrors used as broadband angular reflectors operating at the fixed energy of 8 keV. We summarized our recent investigation of the design, fabrication and performance of depth-graded W/Si, W/C and W/B4C multilayers.