Low-loss Si-slot waveguides and ring resonator embedded with Benzocyclobutene

In order to improve the property of the athermal ring resonator with Si-slot waveguide, a reduction of the propagation loss of a slot waveguide and introduction of a spot-size converter are reported. The propagation loss was measured to be 5.6 dB/cm, which is the lowest value to the best of our knowledge.