Abstract: A fiber optic data transmission system and method are provided comprising a laser diode, an attenuating and focusing lens, and an optical fiber. The method of operating the system attenuates laser diode radiation outputted during operation. The system operates by application of the input driving current to the laser diode in a manner which increases the laser diode extinction ratio. The increased laser diode power output associated with operation at a higher extinction ratio is attenuated by the lens to a safe operating level. Increasing the laser diode extinction ratio significantly increases the system's signal-to-noise ratio and thereby reduces the bit error rate associated with the data transmitted over the optical fiber, while the attenuation of the laser diode output radiation allows operation within prescribed safety limits.