Photonic integrated circuit-based fiber-optic temperature and strain sensing system

A low-cost, multi-function fiber-optic sensing system is highly desirable for physical security monitoring. Using the silicon photonic integrated circuit technology, we propose and demonstrate a compact fiber-optic sensing system which can simultaneously measure the temperature and strain information. A key enabler of the proposed system is an on-chip optical interrogator consisting of a two-dimensional grating coupler, four microring resonators, and four on-chip photodetectors. The interrogator conveys the temperature and strain information via measuring the center wavelength of a fiber Bragg grating and the polarization state of back-reflected light through a single-mode fiber.