A novel silica planar waveguide structure with high thermal efficiency

Silica based integrated planar waveguide technology plays an importance role in the modem optical communication space. Almost all of the current devices made utilize the "channel-waveguide" structure and have poor thermal efficiency in general. A novel silica planar waveguide structure, where a ridge waveguide resides in a vacuum gap, was demonstrated with low insertion loss and significantly higher thermal efficiency. One third of the power was found sufficient to achieve PI phase change for a 5 mm long waveguide, in comparison to the conventional planar lightwave circuits. Simulation results also showed minimal thermal cross talk. Temperature rises in the neighboring channels, resulting from thermal cross talk, are about 1% of the heated channel. No penalty has been observed on the transient thermal response in simulations. The authors believe that this new waveguide structure will lead to low power devices like splitters and variable optical attenuators.