This paper describes the characterization and SPICE model adaptations for a SiGe Heterojunction Bipolar Transistor (HBT) with a characteristic emitter width of 0.4 mum, which is part of the device library in a commercial 0.35 mum SiGe BiCMOS technology. The developed model is used to design and validate the operation of an integrated driver for a 1550 nm Vertical Cavity Surface-Emitting Laser (VCSEL). The static measurements of the driver during irradiation up to 600 kGy correspond well with the simulations. A second irradiation experiment up to 1.6 MGy allowed us to verify the dynamic operation. Investigation of the eye diagram of the output signal both before and after irradiation revealed no significant signal degradation.