Abstract: An optical device structure for use where an optical fiber requires to be accurately aligned in an optically coupled relationship with another optical component in a package 100 comprises an optical fiber 16 mounted in a feedthrough tube 9 which is aligned with a laser 6 through an aperture 18 in a wall 4 of the package 100. The alignment is held by a first alignment means 10, in this case a sleeve spool, which is secured to the wall 4 and to the feedthrough tube 9 relatively close to the wall 4, and by a second alignment means 11, in this case a tubular bushing, which is also fixed to the wall 4 and to the feedthrough tube 9 in a region remote from the wall 4. The use of the two alignment means 10, 11 fixed in this manner permits the desired optical coupling to be accurately fine-tuned in fabrication by a novel technique.