Modified passive alignment of optical fibers with low viscosity epoxy flow running in V-grooves

For conventional passive alignment of optical fibers in optoelectronic packaging, the position of each optical fiber is defined by the geometry of a V-groove. The epoxy is dispensed from the top of the V-groove and another cover plate is usually required to press the fiber against the walls of the V-groove. In the present study, a new technique for epoxy dispensing is developed, where some low viscosity epoxy is dispensed in a "reservoir", flows into the V-groove, and then through the gap between the optical fiber and the V-groove walls. The excess epoxy is diverted to a "canal" next to the "reservoir". It is observed that the flow of epoxy can align the optical fiber by surface tension. Once the fiber is aligned and the epoxy is cured, more epoxy is applied in a glob-top manner for mechanical enhancement. A cover plate is not required. The configuration of the V-groove and associated features, the epoxy dispensing process, and the results of alignment are presented in detail. Experiments show that the optical fiber, which has more than 60 μm initial misalignment, aligns with the centre of the V-grooves within 0.5 μm.