Several groups are presently investigating the opportunity to fabricate miniaturized optical devices characterized by high attachment precision. An automated surface mounted technique based on standardized supports of 10x10x4 mm(3) size and on active insitu alignment of the optical elements had been developed in our laboratories. This surface mounted device (SMD) technique is well suited for a flexible production of small optical devices and it allows a two dimensional layout. It is limited in precision to +/-1 mu m and it is not adapted for further miniaturization. It is briefly described in this paper. Here, we mainly report on a new automated and low cost optical-SMD packaging technique, named "Three Dimensional Miniaturized Optical Surface Mounted Device (TRIMO-SMD)", based on a in-situ active alignment of standardized 2.5x3.5x1 mm(3) elements by a laser soldering reflow process. A sub micron alignment precision is achieved and a attachment strength of similar to 20 N is guaranteed. The technique offers the potential of 3 dimensional layouts and integration on the same layout of electronic and optical elements.