Abstract: An optical fiber feedthrough comprising a glass seal for sealing the optical fiber within a metal sleeve. The fiber is held in a fixed position with respect to the sleeve while a glass solder, preferably an annular preform, is heated to its glass transition temperature and then cooled to form a glass to metal seal.

Abstract: A method of mounting a saw device comprising applying metallized areas to the surface of an appropriate substrate, attaching conductive leads to the metallized areas, locating the said surface adjacent a selected area of another substrate so that said leads contact conductive regions on the second substrate and attaching said leads to said conductive regions on the second substrate so that the first substrate is supported on the leads and the conductive regions.

Abstract: A termination for an optical fibre includes a planar support block which has an aperture there-through for receiving and accurately locating an optical fibre end. It is constructed out of a plurality of platelets, the aperture being provided by aligned, laser-drilled holes which are formed in each platelet. The holes, which are characteristically tapered, all taper in the same direction. They can therefore act as guides during insertion of a fibre end. Alternative arrangements are described. The termination is for use wherever an optical fibre must be accurately located relative to another component. If finds particular application as a support for a rear-entry photodiode.

Abstract: A SAW device is formed by applying metallized areas (11) to a surface of a SAW substrate (10) and attaching conductive leads (18) to the metallized areas. The substrate is inverted and located on a hybrid circuit so that the leads (18) contact and are supported on conductive areas (30) of the circuit. This mounting arrangement minimizes the stresses which occur in the substrate in its operational life. A novel shape for the device is also disclosed.