Athermalizing and Trimming of Slotted Silicon Microring Resonators With UV-Sensitive PMMA Upper-Cladding

This letter experimentally demonstrates significant reduction in the resonance thermal sensitivity of the slotted silicon microring resonators by exploiting polymethyl methacrylate (PMMA) as upper-cladding. We investigate the resonance temperature dependence on the slot width with and without PMMA upper-cladding. The experimental results show that the temperature dependence is reduced from 91 pm/degrees C for a regular microring resonator to 27 pm/degrees C for the PMMA-clad slotted microring resonator. The ultraviolet (UV) sensitive PMMA upper-cladding also allows the resonance wavelengths of slotted microring resonators shift by 0.5 nm under UV light trimming. With the demonstrated schemes, each individual optical component can be athermalized and precisely registered to standard wavelengths for a future multiwavelength optically interconnected computing system-on-a-chip.