Encapsulating Planar Waveguide-Based Photonic Components with Polymer Coatings

Polymer encapsulation was applied to protect waveguide-based photonic components from moisture attack at the lowest cost. A thin-coating method was developed by analyzing the water transportation in polymers and by evaluating the impact of encapsulation on the waveguides. The results showed that a 7 μm-thick Parylene coating can provide sufficient protection to the wire bonds and fiber-to-waveguide coupling materials. The coated variable optical attenuator easily passed the damp heat test of Telcordia GR 1221. This coating did not have any stress or heat effect on the components, and it costs 90% less than hermetic packaging.