Analyzing voltage bias and temperature induced aging effects in photonic interconnects for manycore computing

Silicon photonic interconnects are being considered for integration in future networks-on-chip (NoCs) as they can enable higher bandwidth and lower latency data transfers at the speed of light. Such photonic interconnects consist of photonic waveguides with dense-wavelength-division-multiplexing (DWDM) for signal traversal and microring resonators (MRs) for signal modulation and detection. To enable MRs to modulate and detect DWDM photonic signals, carrier injection in MRs through their voltage biasing is essential. But long-term operation of MRs with constant or time-varying temperature and voltage biasing causes aging. Such voltage bias temperature induced (VBTI) aging in MRs leads to resonance wavelength drifts and Q-factor degradation, which increases signal loss and energy delay product in photonic NoCs (PNoCs) that utilize photonic interconnects. This paper explores VBTI aging in MRs and demonstrates its impacts on PNoC architectures for the first time. Our system-level experimental results on two PNoC architectures indicate that VBTI aging increases signal loss in these architectures by up to 7.6dB and increases EDP by up to 26.8% over a span of 5 years.