Abstract: An apparatus and method for generating a mode-scrambled optical signal. A laser beam source directs an optical signal into a free end of a first segment of multimode fiber comprising a graded-index (GI) fiber core at an offset from the centerline of the core, generating an offset-launch condition. The first segment of multimode fiber is operatively coupled into a second segment of multimode fiber comprising a step-index (SI) fiber core. As the offset-launched optical signal passes through the first and second segments of multimode fiber, the optical signal is converted into a mode-scrambled optical signal having a substantially-filled numerical aperture.

Abstract: Disclosed is an alloy steel of high corrosion resistance to hot molten salts containing chlorides and/or alkali oxides. The alloy steel is manufactured from a composition comprising 20-40 weight % of Ni, 0-8 weight % of Cr, 0.05 weight % or less of C, 0.5 weight % or less of Si, 1.0 weight % or less of Mn, 0.05 weight % or less of S, and the balance of Fe to total weight. With a low Cr content, the alloy steel is superb in the corrosion resistance to chloride and/or alkali oxide-containing molten salts, including LiCl—Li2O. Also, the alloy steel shows stable corrosion resistance to molten salts even at high temperature as well as low temperature in addition to being superior to workability. Thus, the alloy steel can be processed into plates, bars or pipes which are used for structural materials and structural components for treating molten salts.