High Refractive Index Chalcogenide Hybrid Inorganic/Organic Polymers for Integrated Photonics

Abstract: Optical polymer-based integrated photonic devices are gaining interest for applications in optical packaging, biosensing, and augmented/virtual reality (AR/VR). The low refractive index of conventional organic polymers has been a barrier to realizing dense, low footprint photonic devices. The fabrication and characterization of integrated photonic devices using a new class of high refractive index polymers, chalcogenide hybrid inorganic/organic polymers (CHIPs), which possess high refractive indices and lower optical losses compared to traditional hydrocarbon-based polymers, are reported. These optical polymers are derived from elemental sulfur via the inverse vulcanization process, which allows for inexpensive monomers to be used for these materials. A facile fabrication strategy using CHIPs via lithography is described for single-mode optical waveguides, Y junction splitters, multimode interferometers (MMIs), and high Q factor ring resonators, along with device characterization. Furthermore, propagation losses of 0.4 dB cm⁻¹ near 1550 nm wavelength, which is the lowest measured loss in non-fluorinated optical polymer waveguides, coupled with the benefits of low cost materials and manufacturing are reported. Ring resonators with Q factor on the order of 6 × 10⁴ and cavity finesse of 45, which are some of the highest values reported for optical polymer-based ring resonators, are also reported.