Bipolar components (diodes, transistors, thyristors) are essential for very high-voltage power electronics. Recently, an optical high-voltage 4H-SiC BJT (Bipolar Junction Transistor) has been designed, fabricated and characterized. The BJTs were fabricated on a 4H-SiC wafer using a 120 μm thick epilayer with a doping concentration of 8×1014 cm−3 [1] and were designed to withstand a voltage of 10 kV. After electrical characterization, a breakdown voltage of about 11 kV was obtained [2]. PiN diodes have been integrated in the mask layout as part of this project to optically trigger high-voltage bipolar components (Fig. 1, right). In order to verify the effectiveness of their peripheral protection, different geometries were considered: MESA only, MESA combined with JTE, with and without supplementary 6 JTE rings, with round and square shapes. These diodes have been characterized in a vacuum chamber up to a reverse voltage of 1000 V and exhibit a low leakage current as shown in Fig. 1, a prerequisite for OBIC characterization measurements in reverse. This paper aims to demonstrate how the micro-OBIC technique [3] can be used to assess the efficiency of peripheral protection by analyzing the 2D distribution map of the currents within the device structure, particularly at the junction periphery. 2 types of circular diodes were chosen for illustration: a MESA diode and a MESA diode with JTE and 6 rings. Micro-OBIC measurements were carried out in air, limiting the reverse voltage applied to avoid breakdown. The OBIC 2D-maps are shown in Fig. 2, where the junction is clearly evidenced. At the same time, finite element simulations were carried out with SentaurusTM [4] in transient mode, taking into account the diode structure (Fig. 3) and the characteristics of the laser optical beam. Simulations of this kind are rare [5] and time-consuming. Fig. 4 shows currents as a function of diode diameter for the diode protected with the MESA. As it can be observed, both the experimental and simulated OBIC behavior are almost identical: the optically induced current increases and widens at the junction if the reverse voltage increases. Acknowledgements for French ANR contract HV-PhotoSwitch (ANR-18-CE05-0020-01).