Abstract: A compression coupling system is employed for attaching one optical or electro-optical component to another in a manner such that different diameters of devices readily may be coupled together without causing any cosmetic defects from the coupling function. The first component to which the other component is to be attached has a cylindrical portion on it; and the other component has a hollow cylindrical extension on it, with an internal diameter which is equal to or greater than the external diameter of the first component. A cylindrical sleeve/shim having a thickness which is equal to the difference between the external diameter of the first component and the internal diameter of the extension is placed between the two devices which then are fitted, one over the other. A compression ring and locking ring secure the devices together by compressing the locking ring onto the body of the first component.