UC Berkeley

Label-free miniaturized optical sensors can have a tremendous impact on highly sensitive and scalable Point-of-Care (PoC) diagnostics by monitoring in real-time molecular interactions without any labels. However, current biophotonic platforms are limited by complex optical and external readout equipment, precluding their use in a PoC setting. In this research, we aim to address this challenge by developing a first of its kind fully integrated electronic-photonic real-time label-free molecular sensor utilizing micro-ring resonators (MRRs) co-integrated with on-chip electronics in a high volume advanced electronic process. This technology will reduce cost and enable self-contained and miniaturized Point-of-Care devices that are needed in healthcare applications.

This thesis introduces an arrayed electronic-photonic system-on-chip (EPSoC) in GlobalFoundries (GF) 45nm RFSOI with 60 5μm radius MRRs connected to on-chip receivers, approaching a limit of detection (LoD) equivalent to a single 140nm viral particle. In order to deliver multiple fluidic solutions and enable multi-analyte sensing, we propose an efficient packaging strategy for fabricating multi-channel microfluidic networks interfacing with mm-scale chips. Leveraging co-integration of planar MRRs with on-chip receivers, we eliminate the need for a tunable laser and external readout equipment by shifting the requirements of resonance tuning and readout processing to the electronic domain. To further enhance the LoD we propose a dual-ring phase-based sensing architecture, boosting the system’s sensitivity by 3.7x compared to intensity-based single MRR schemes. The inherent intrinsic limitations of MRRs due to environmental variations are addressed with an on-chip differential scheme using sensing and reference rings to cancel common mode errors. We demonstrate the sensing capabilities of the EPSoC by monitoring in real-time binding events of proteins and nanoparticles, unlocking the door towards self-contained fully integrated Lab-on-Chip (LoC) photonic sensors for PoC applications.