Uneven curing induced interfacial delamination of UV adhesive-bonded fiber array in V-groove for photonic packaging

The common approach to attaching a large number of fibers to a guided-wave device is to fabricate a linear array using V-grooves. UV-curable adhesives are used to attach the fiber in V-groove for the fabrication of fiber array. Interfacial delaminations at the adhesive fiber interfaces are common after the reliability test due to uneven curing of the UV adhesive. This paper investigated the causes of uneven curing that gave rise to delamination. An analytical ray tracing technique was used to estimate the variation in light intensity or shadowing during the UV curing of adhesive. These effects were found to be very severe when the refractive index difference between the adhesive and the cladding materials is very large. Based on this study, it can be concluded that the delamination problem can be minimized by selecting a UV-curable adhesive having the same refractive index of the cladding material. It is also recommended to light illuminate from the topside for fiber packaging. © 2006 IEEE.