A Radiation-Hardened Fiber-Optic Transmission System Having a 400-MHz Bandwidth and Linear Response

A radiation-hardened fiber-optic signal transmission system has been built that has a bandwidth of over 400 MHz with linear response. An amplitude-modulated CW laser diode is used in the transmitter. Automatic bias compensation is applied to the laser in lieu of the typical temperature control. The system has provision to remotely select (via a fiber-optic control link) the attenuation between the signal input and the transmitter. A self-contained system-calibration pulse is also remotely triggerable. The transmitter has a volume of about 75 in3, including the battery power supply. The rise time of the system is 1.2 ns and the dynamic range is 35 dB. The transmitter and fiber-optic portions of the system are hardened to withstand a photon irradiation of more than 5 × 105 rad(Si)/s from a Febetron 705.