Compact ring resonator enhanced silicon metal-semiconductor-metal photodetector in SiN-on-SOI platform

We present a compact on-chip resonator enhanced silicon metal-semiconductor-metal(MSM) photodetector in 850nmwavelength band for communication and lab-on-chip bio-sensingapplications. We report the highest responsivity of 0.81 A/W for a 5μm long device. Highresponsivity is achieved by integrating the detector in a silicon nitride ring resonator. Theresonance offers 100X responsivity improvement over a single-pass photodetector due to cavityenhancement. We also present a detailed study of the high-speed response of the cavity andsingle-pass detector. We report an electro-optic bandwidth of 7.5 GHz measured using afemtosecond optical excitation. To the best of our knowledge, we report for the first time siliconnitride resonator integrated Si-MSM detector in SiN-SOI platform.