Polymer Microrings Integrated With Thin Film InGaAs MSM Photodetectors For Sensor-On-A-Chip Applications Sang-Yeon Cho Electrical and Computer Engineering Fitzpatrick Institute for Photonics Duke University

Chip Scale Sensory Systems with Integrated Active Optical Components Integrated Active Optical Components (Optical Source, Photodetectors) Chemically Selective & Highly Sensitive Microresonator Sensor Arrays Stability in Optical Alignment and Polarization

Background: Microresonators (Circulating & Transmitted Power vs Phase Shifts)

Four Port Polymer Microresonators (Through Port vs Drop Port) Fabricated SU8 microring with 100 mm radius, 1 mm directional (straight) coupling section

Polymer Orthogonal Microdisk Sensors Radius= 100 mm with 10 mm straight coupling section SU-8 waveguide = 2 mm wide and 1.5 mm thick

Orthogonal Microresonators (Field Configuration and Output Characteristics)

Measured and Calculated Output of the Fabricated Microdisk Sensor The measured mode spacing of the microdisks was 2.28 nm between 1545nm and 1565nm in the output spectrum (dots: measured spectrum, solid line: calculated)

Resonant Wavelength Shift in Orthogonal Microresonator Sensors neff= 1.500 neff= 1.505 neff= 1.510 t1=t2=0.9, a=0.99, and, R=100 mm

Resonant Wavelength Shifts in the Microdisk Sensors for Glucose Sensing Glucose concentrations in DI water (1.10 wt%, 1.82 wt%, 3.03 wt%, 5.75 wt% and 6.96 wt% ) The estimated sensitivity : 0.12 [nm/wt%]

Fabricated Polymer Microring Integrated with Thin Film InGaAs MSM PD 50 mm by 50 mm active area 1 mm thick SU8 Microring Radius= 100 mm with 10 mm straight coupling section SU-8 waveguide 2 mm wide and 1.5 mm thick

Spectral Response Measurement Setup

Measured Spectral Response of the Fabricated Microring and Integrated Thin film MSM PD The measured and calculated spacing in the resonant peaks near l=1557nm are 2.36 nm and 2.46 nm, respectively.

Conclusions Polymer microresonators have been fabricated and characterized. Orthogonal SU8 microdisk sensors have been fabricated and tested with different glucose concentrations. Polymer microring resonators integrated with thin film MSM photodetector demonstrated for chip scale sensor applications. Measured photocurrent from the integrated thin film MSM photodetector were in good agreement with the spectral response of the microring resonator.