Radiation testing of optical fibers and phototransistors

Abstract EN

Tests have been performed to examine the effect$ (١۴ y-exposure on opto-electronic components that can be used in digital fiber optic data links.

The response of fiber wave guides to ionizing radiation has been studied.

Measurements of the growth and decay of the radiation induced loss at 850 nm and 1300 nm have revealed that fibers are sensitive to y-dose.

In addition, a linear dependence of short circuit current on y-dose rate, up to 380 rad/sec, for the photodiode was shown.

At very high dose levels, permanent damage is noticed in the diode characteristics and its current decreases, where a value of 1600 |J.A, measured at light intensity level of 8000.0 lux, dropped to 1200, 950, 820, ?00, 600, and 550 |J.A after y-exposure up to 2.0, 16, 38, ?0, 105, and 140 Mrad respectively.

Also, the forward current gain factor of phototransistors, measured as a function of operating collector current, shows a severe decrease due to y-exposure.

The damage effect has minima that usually corresponds to the lower and higher ends of the operating collector current range of a device.

Finally, proposals using photodiodes for gamma dose- and dose rate-dosimetry are given, tested, and proved to be quite satisfactory.