Slot-Track Micro-Ring Assisted Mach-Zender Interferometric Optical Electric Field Sensor

Within the framework of “clean, low-carbon, and smart integration,” a pivotal element of the global energy Internet digital transformation lies in sensing technology. This paper addresses the enhancement of optical electric field sensors by investigating a technique grounded in the electric-optical energy coupling principle. A physical model is devised for electric field sensors, employing micro-ring-assisted Mach-Zender interferometric (MZI) structures with a slot-track architecture. Subsequently, a simulation method is employed to delineate the influence of the device's major structural parameters on the sensor's performance. Chip-based optical electric field sensors, coated with electro-optic polymer films, are then fabricated. Finally, a test platform is established to conduct an analysis encompassing time-frequency domain characterization and sensitivity of the sensor. The experimental findings demonstrate that the electric field sensor exhibits commendable linear input/output characteristics within an AC electric field ranging from 5.7 kV/m to 148.2 kV/m at industrial frequencies. The sensor achieves a sensitivity of 0.945 mV/(kV/m). Across high, medium, and low-frequency sinusoidal electric fields spanning from 50 Hz to 13.56 MHz, the sensor response exhibits no noteworthy aberrations or delays. The sensor performs adeptly in tracking and responding to strong transient electric fields within the μs range. Additionally, a comparative analysis with control sensor test results affirms that the slot-track resonant micro-ring structure devised in this paper significantly enhances the sensor's sensitivity and linear dynamic range. The sensor also exhibits good temperature stability in the 0 °C to 75 °C range. The research outcomes presented herein offer technical support for the multifaceted application of this technology in electric field measurement.