Fabrication and characterization of a dual layer multiple refractive index benzocyclobutene polymer platform for integrated optical devices

A dual layer Benzocyclobutene (BCB) polymer with tailored refractive index values is successfully fabricated using different curing processes, forming a platform for integrated optical devices. The dual layer BCB polymer could potentially solve the high index contrast issue associated with existing glass–polymer structure, which require sub-micron precision when producing single-mode waveguides. Although the two BCB layers display similar physical properties, they have significantly different optical and chemical characteristics. The different curing processes for the undercladding and core layers led to these differences. Single mode waveguides fabricated via photolithography were also demonstrated with an average propagation loss of 2 dB/cm.