Performance Investigation of VCSEL-Based Voltage Probe and Its Applications to HPEM Effects Diagnosis of Embedded Systems

The achievable performances of bias-free vertical-cavity surface-emitting laser (VCSEL)-based voltage probe for high-power electromagnetic (HPEM) effects diagnosis of embedded systems are investigated. The minimum driving current needed by VCSEL is calculated to design the probes with high input impedance and high applicable data bit rate (BR) simultaneously. The VCSEL-based probes for 5 V/3.3 V logic family ICs are designed with a kind of 850-nm VCSEL and a family of high-frequency chip resistors. Measurement results show that the VCSEL-based voltage probe's input impedance can maintain higher than 1 kΩ until 300 MHz. The bit error ratio (BER) test shows that the voltage probe is applicable for monitoring digital signals with BR below 280 Mb/s, while the monitoring BER is better than 1E-6 for BR below 200 Mb/s. The processes of disturbance and breakdown effects induced to a minisized drone circuit are successfully captured by the voltage probe in a pulse injection test, demonstrating the compact and fiber output voltage probe's potential value in diagnosing embedded system's HPEM effects in system-level test.