Two sub-assemblies in a fiber optic device are fitted to mounting faces of a
central section. The mounting faces are typically flat and mutually orthogonal,
thus permitting the adjustment of the two sub-assemblies in decoupled degrees of
freedom. This results in a simpler adjustment procedure for aligning the two sub-assemblies.
Furthermore, the mounting of the sub-assemblies using the orthogonal mounting faces
permits the use of relatively thin layers of adhesive that reduce misalignment
problems arising from mismatched thermal expansion when the temperature changes.
