This paper describes the fabrication and, in particular, the assembly processes of a miniaturized micro-optical system, to be integrated on a hybrid flexible module, which hosts also electronics and microsensors. The whole module was conceived to be mass-produced in order to be distributed in skin-like structures for robotic tactile applications. Nevertheless, it is generally suitable for sensing applications where the flexibility and the thickness of the sensing network are primary requirements. The micro-optical system works as a part of an optoelectronic transducer where electric signals, generated by tactile MEMS sensors, are computed by a microcontroller that drives the micro-optical system. This consequently generates optical radiation, by means of integrated light emitting diodes (LEDs), to be coupled into optical fibers, which waveguide signals to a CMOS optical sensor. Micro-machining and micro-assembly processes of miniaturized components are critical steps in order to fabricate many of these modules according to the application requirements.