All-Silicon Photodetectors for Photonic Integrated Circuit Calibration

All-silicon highly-doped PN junction-based photodetectors, for photonic integrated circuit (PIC) calibration and power monitoring, are designed and fabricated in the C-band. The photodetector response is measured for different doping conditions. The photodetectors are integrated with an interferometric based phase-interrogator structure for a test calibration circuit. The measured devices show high responsivity (12 A/W) obtained under avalanche condition at 5.7 V reverse bias and reasonable dark current ( $1~\mu \text{A}$ ) due to photon assisted tunneling effect and are therefore, proved to be an ideal candidate for power monitoring and phase calibration of PICs.