Design and Assessment of a High Gamma-Dose Tolerant VCSEL Driver With Discrete SiGe HBTs

Abstract

A digital VCSEL driver has been designed, simulated and assessed under radiation, using discrete SiGe HBTs. The circuit tolerates high levels of gamma radiation, up to 12 MGy, features less than 2% drift in the forward current of the VCSEL and operates well above 10 MHz. The output duty cycle shows no notable degradation at 200 kHz, enabling the design of robust analog and digital communication systems using pulse-width-modulation (PWM) schemes.Index Terms-International experimental thermonuclear fusion reactor (ITER), laser driver, optical transmitter, radiation effects, SiGe HBT, vertical-cavity surface-emitting laser (VCSEL).