High yield coaxial-type laser module packages using on-line monitoring system

The laser-welded coaxial-type laser module packages using an on-line monitoring system (OLMS) is presented. The OLMS is integrated with an ultra high precision laser displacement meter (LDM) and a laser welding system that enables to quantitatively on-line process the successive postweld shift (PWS) measurements by the LDM and corrections by the laser welding during multiple welding compensations in laser-welded laser module packages. The results show that the high-yield laser module packages with high coupling efficiency of 86–97% are obtained. The fiber shifts due to the PWS could be realigned back closer to their original position after applying multiple welding compensations, and hence the coupling powers loss due to the PWS could be recovered. This OLMS study has provided a practical package guideline for fabricating reliable laser module packages with high yield and high coupling efficiency for use in low-cost lightwave transmission systems.